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Carbidopa/levodopa | Carbidopa/levodopa, also known as levocarb and co-careldopa, is the combination of the two medications carbidopa and levodopa. It is primarily used to manage the symptoms of Parkinsons disease, but it does not slow down the disease or stop it from getting worse. It is taken by mouth. It can take two to three weeks of treatment before benefits are seen. Each dose then begins working in about ten minutes to two hours with a duration of effect of about five hours.Common side effects include movement problems and nausea. More serious side effects include depression, low blood pressure with standing, sudden onset of sleepiness, psychosis, and increased risk-taking behavior. Carbidopa prevents the breakdown of levodopa outside the brain. In the brain, levodopa is broken down into dopamine, its active form. Carbidopa also helps prevent some of the nausea which levodopa causes.It is on the World Health Organizations List of Essential Medicines. It is available as a generic medication. In 2018, it was the 169th most commonly prescribed medication in the United States, with more than 3 million prescriptions.
Medical uses
Parkinsons disease
It is primarily used to improve the symptoms of Parkinsons disease but does not change the course of the disease. It can take two to three weeks of treatment before benefits are seen. Each dose then begins working in about ten minutes to two hours depending on the formulation, with a duration of effect of about five hours.A formulation that can be given in an intra-intestinal pump, known as Duodopa, is being developed.
Other
Other uses include for dopamine-responsive dystonia (DRD) and restless legs syndrome.There is tentative evidence that it is useful in amblyopia when used with other treatments.
Side effects
Common side effects include dizziness, drowsiness, blurred vision, vomiting, nausea, dry mouth, low appetite, heartburn, diarrhea, constipation, frequent sneezing, stuffiness of the nose, any of the symptoms of ordinary common cold, cough, muscle pain, hallucinations, numbness or a tingling sensation, disturbances of sleep, skin rash, itching, and/or headache.Less common, but more serious, side effects can include very frequent blinking or twitching of the eyes, fainting, mood changes such as confusion, depression, hallucinations, thoughts of suicide, or unusual strong urges (such as increased gambling), increases in the sex-drive, delusions (strongly-felt belief in something which is obviously not true), worsening of involuntary movements or spasms, and/or other movement problems. Patients should report these to their doctors as soon as possible.
Mechanism of action
Levodopa is converted to dopamine via the action of a naturally occurring enzyme called DOPA decarboxylase. This occurs both in the peripheral circulation and in the central nervous system after levodopa has crossed the blood brain barrier. Activation of central dopamine receptors improves the symptoms of Parkinsons disease; however, activation of peripheral dopamine receptors causes nausea and vomiting. For this reason levodopa is usually administered in combination with a DOPA decarboxylase inhibitor (DDCI), in this case carbidopa, which is very polar (and charged at physiologic pH) and cannot cross the blood brain barrier, however prevents peripheral conversion of levodopa to dopamine and thereby reduces the unwanted peripheral side effects of levodopa. Use of carbidopa also increases the quantity of levodopa in the bloodstream that is available to enter the brain.
History
In 1960 the Austrian biochemist Oleh Hornykiewicz, while at the University of Vienna, examined results of autopsies of patients who had died with Parkinsons disease. He suggested that the disease was associated with, or caused by, a reduction in the levels of dopamine in the basal ganglia of the brain. Since dopamine itself did not enter the brain, he tried treating twenty patients with a racemic mixture of dihydroxyphenylalanine (DOPA), which could enter the brain and be converted there to dopamine by the action of DOPA decarboxylase. His results were positive, as were those of another trial in Montreal run by André Barbeau. Unfortunately, other investigators were unable to replicate these early results, and the use of DOPA remained in question until 1967, when George Cotzias at the Brookhaven National Laboratories in Upton, New York, used megadoses of DOPA, up to 16 grams per day. Not long after these results became known, Curt Porter at Merck showed that L-DOPA was the active stereoisomer, thus reducing the effective dose to half.With L-DOPA identified as the active form, Alfred Pletscher and his colleagues at Hoffman-LaRoche synthesized benserazide, an inhibitor of DOPA decarboxylase, which further reduced the required dose. A drug combining L-DOPA with benserazide was marketed under the brand name of Madopar. Independent work was carried out by Victor Lotti at Merck in West Point, Pennsylvania. Merck had already synthesized and patented carbidopa, another dopa decarboxylase inhibitor in 1962, and in 1971 Lotti showed that the use of the L-form of carbidopa, further reduced the therapeutic dose of L-DOPA. The combination of L-carbidopa and L-DOPA was marketed under the brand name of Sinemet.
Society and culture
Cost
It is available as a generic medication and is moderately expensive.
Names
The generic name under the BAN system is Co-careldopa.
It is sold under several brand names, including Sinemet (Merck Sharp & Dohme Limited), Pharmacopa, Atamet, Apo-Levocarb, Duodopa, Kinson, and Pharmacopa, among others.
Extended-release formulations are sold as Rytary and Sinemet-CR. An extended-release enteral solution is sold as Duopa.
Shortages
In 1991, Merck licensed the rights to the manufacture and sale of Sinemet to a newly created joint venture, DuPont Merck Pharmaceutical Company. That same year, approvals for a sustained release formulation (Sinemet CR) which could be taken less frequently were also obtained. DuPont purchased Mercks share in the joint venture in 1998 and began operating the company as DuPont Pharmaceuticals (DuPont Pharma), but Merck continued to manufacture the drug for DuPont. Starting in late 2009 and continuing into 2011 Merck stopped manufacturing the drug while awaiting regulatory approvals due to a change in the supplier of the active ingredient. This resulted in shortages of the brand name products Sinemet and Sinemet CR, although alternative generic versions were still available.Another shortage appears to have occurred at the end of 2017.
See also
Stalevo in combination with entacapone
References
External links
"Carbidopa mixture with levodopa". Drug Information Portal. U.S. National Library of Medicine. |
Liothyronine | Liothyronine is a manufactured form of the thyroid hormone triiodothyronine (T3). It is most commonly used to treat hypothyroidism and myxedema coma. It can be taken by mouth or by injection into a vein.Side effects may occur from excessive doses. This may include weight loss, fever, headache, anxiety, trouble sleeping, arrythmias, and heart failure. Use in pregnancy and breastfeeding is generally safe. Regular blood tests are recommended to verify the appropriateness of the dose being taken.Liothyronine was approved for medical use in 1956. It is available as a generic medication. In 2019, it was the 230th most commonly prescribed medication in the United States, with more than 2 million prescriptions.
Medical uses
Liothyronine may be used when there is an impaired conversion of T4 to T3 in peripheral tissues. The dose of liothyronine for hypothyroidism is a lower amount than levothyroxine due it being a higher concentrated synthetic medication. About 25 μg of liothyronine is equivalent to 100 μg of levothyroxine.In thyroid cancer or Graves disease, ablation therapy with radioactive iodine (131I) can be used to remove trace thyroid tissue that may remain after thyroidectomy (surgical excision of the gland). For 131I therapy to be effective, the trace thyroid tissue must be avid to iodine, which is achieved by elevating the persons TSH levels. For patients taking levothyroxine, TSH may be boosted by discontinuing levothyroxine for 3–6 weeks. This long period of hormone withdrawal is required because of levothyroxines relatively long biological half-life, and may result in symptoms of hypothyroidism in the patient. The shorter half-life of liothyronine permits a withdrawal period of two weeks, which may minimize hypothyroidism symptoms. One protocol is to discontinue levothyroxine, then prescribe liothyronine while the T4 levels are falling, and finally stop the liothyronine two weeks before the radioactive iodine treatment.Liothyronine may also be used for myxedema coma because of its quicker onset of action when compared to levothyroxine. Use for the treatment of obesity is not recommended.
Depression
Adding liothyronine to tricyclic antidepressants appears useful, especially in women. An algorithm developed from the STAR*D trial recommends liothyronine as an option when people have failed two antidepressant medications.
Pregnancy
Per the U.S. FDA, liothyronine is categorized as Pregnancy Category A. Thyroid hormone is minimally transferred to the fetus or placenta, however as of October 2014, studies have not shown any adverse effects to the fetus. Hypothyroid mothers should continue to take thyroid hormone replacement therapy throughout pregnancy to avoid adverse events.
Nursing
Breastmilk contains a low amount of thyroid hormone, so it is important to exercise caution when breastfeeding while taking liothyronine.
Elderly
Older people should be started on lower doses of liothyronine. Plasma T3 concentrations in this population are decreased by 25% to 40%. TSH must be routinely monitored since there is a risk of coronary artery disease, hyperthyroidism and excessive bone loss from inadequate or abnormal thyroid replacement.
Contraindications
Any person with a hypersensitivity to liothyronine sodium or any active ingredient of the formulation should not be on this medication. If there is uncorrected adrenal insufficiency or thyrotoxicosis, a different approach to therapy must be considered.
Side effects
Liothyronine may cause a number of side effects, mostly similar to symptoms of hyperthyroidism, which include:
weight loss
tremor
headache
upset stomach
vomiting
diarrhea
stomach cramps
nervousness
irritability
insomnia
excessive sweating
increased appetite
fever
changes in menstrual cycle
sensitivity to heat
Boxed warning
The package insert contains the following boxed warning, as do all thyroid hormones:
Drugs with thyroid hormone activity, alone or together with other therapeutic agents, have been used for the treatment of obesity. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects.
Pharmacology
Liothyronine is the most potent form of thyroid hormone. As a salt of triiodothyronine (T3), it is chemically similar and pharmacologically equivalent to T3. As such, it acts on the body to increase the basal metabolic rate, affect protein synthesis and increase the bodys sensitivity to catecholamines (such as adrenaline) by permissiveness. As monotherapy or in combination therapy with SSRIs, liothyronine may also enhance generation of new neurons in the central nervous system. The thyroid hormones are essential to proper development and differentiation of all cells of the human body. These hormones also regulate protein, fat, and carbohydrate metabolism, affecting how human cells use energetic compounds.
In comparison to levothyroxine (T4), liothyronine has a faster onset of action as well as a shorter biological half-life, which may be due to less plasma protein binding to thyroxine-binding globulin and transthyretin.
Pricing
The British Competition and Markets Authority launched an investigation into the alleged "excessive and unfair pricing" of liothyronine tablets in 2017. It alleged that Advanz Pharma overcharged the NHS from before 2007 to July 2017. The price of a pack increased by almost 1,600% from £4.46 before it was debranded in 2007 to £258.19 by July 2017.
References
External links
"Liothyronine". Drug Information Portal. U.S. National Library of Medicine. |
Acetylcysteine | Acetylcysteine, also known as N-acetylcysteine (NAC), is a medication that is used to treat paracetamol overdose and to loosen thick mucus in individuals with chronic bronchopulmonary disorders like pneumonia and bronchitis. It has been used to treat lactobezoar in infants. It can be taken intravenously, by mouth, or inhaled as a mist. Some people use it as a dietary supplement.Common side effects include nausea and vomiting when taken by mouth. The skin may occasionally become red and itchy with any route of administration. A non-immune type of anaphylaxis may also occur. It appears to be safe in pregnancy. For paracetamol overdose, it works by increasing the level of glutathione, an antioxidant that can neutralise the toxic breakdown products of paracetamol. When inhaled, it acts as a mucolytic by decreasing the thickness of mucus.Acetylcysteine was initially patented in 1960 and came into medical use in 1968. It is on the World Health Organizations List of Essential Medicines. It is available as a generic medication and is inexpensive.The sulfur-containing amino acids cysteine and methionine are more easily oxidized than the other amino acids.
Uses
Paracetamol overdose
Intravenous and oral formulations of acetylcysteine are available for the treatment of paracetamol (acetaminophen) overdose. When paracetamol is taken in large quantities, a minor metabolite called N-acetyl-p-benzoquinone imine (NAPQI) accumulates within the body. It is normally conjugated by glutathione, but when taken in excess, the bodys glutathione reserves are not sufficient to deactivate the toxic NAPQI. This metabolite is then free to react with key hepatic enzymes, thereby damaging liver cells. This may lead to severe liver damage and even death by acute liver failure.
In the treatment of paracetamol (acetaminophen) overdose, acetylcysteine acts to maintain or replenish depleted glutathione reserves in the liver and enhance non-toxic metabolism of acetaminophen. These actions serve to protect liver cells from NAPQI toxicity. It is most effective in preventing or lessening hepatic injury when administered within 8–10 hours after overdose. Research suggests that the rate of liver toxicity is approximately 3% when acetylcysteine is administered within 10 hours of overdose.Although IV and oral acetylcysteine are equally effective for this indication, oral administration is generally poorly tolerated due to the higher dosing required to overcome its low oral bioavailability, its foul taste and odour, and a higher incidence of adverse effects when taken by mouth, particularly nausea and vomiting. Prior pharmacokinetic studies of acetylcysteine did not consider acetylation as a reason for the low bioavailability of acetylcysteine. Oral acetylcysteine is identical in bioavailability to cysteine precursors. However, 3% to 6% of people given intravenous acetylcysteine show a severe, anaphylaxis-like allergic reaction, which may include extreme breathing difficulty (due to bronchospasm), a decrease in blood pressure, rash, angioedema, and sometimes also nausea and vomiting. Repeated doses of intravenous acetylcysteine will cause these allergic reactions to progressively worsen in these people.
Several studies have found this anaphylaxis-like reaction to occur more often in people given intravenous acetylcysteine despite serum levels of paracetamol not high enough to be considered toxic.
Lungs
Inhaled acetylcysteine has been used for mucolytic ("mucus-dissolving") therapy in addition to other therapies in respiratory conditions with excessive and/or thick mucus production. It is also used post-operatively, as a diagnostic aid, and in tracheotomy care. It may be considered ineffective in cystic fibrosis. A 2013 Cochrane review in cystic fibrosis found no evidence of benefit.Acetylcysteine is used in the treatment of obstructive lung disease as an adjuvant treatment.
Kidney and bladder
Evidence for the benefit of acetylcysteine to prevent radiocontrast induced kidney disease is mixed.Acetylcysteine has been used for cyclophosphamide-induced haemorrhagic cystitis, although mesna is generally preferred due to the ability of acetylcysteine to diminish the effectiveness of cyclophosphamide.
Psychiatry
Acetylcysteine has been studied for major psychiatric disorders, including bipolar disorder, major depressive disorder, and schizophrenia.Tentative evidence exists for N-acetylcysteine also in the treatment of Alzheimers disease, autism, obsessive-compulsive disorder, specific drug addictions (cocaine), drug-induced neuropathy, trichotillomania, excoriation disorder, and a certain form of epilepsy (progressive myoclonic). Preliminary evidence showed efficacy in anxiety disorder, attention deficit hyperactivity disorder and mild traumatic brain injury although confirmatory studies are required. Tentative evidence also supports use in cannabis use disorder.
Bipolar disorder
In bipolar disorder, N-acetylcysteine has been repurposed as an augmentation strategy for depressive episodes in light of the possible role of inflammation in the pathogenesis of mood disorders. Nonetheless, meta-analytic evidence shows that add-on N-acetylcysteine was more effective than placebo only in reducing depression scales scores (low quality evidence), without positive effects on response and remission outcomes, limiting its possible role in clinical practice to date.
Addiction
Evidence to date does not support the efficacy for N-acetylcysteine in treating addictions to gambling, methamphetamine, or nicotine. Based upon limited evidence, NAC appears to normalize glutamate neurotransmission in the nucleus accumbens and other brain structures, in part by upregulating the expression of excitatory amino acid transporter 2 (EAAT2), a.k.a. glutamate transporter 1 (GLT1), in individuals with addiction. While NAC has been demonstrated to modulate glutamate neurotransmission in adult humans who are addicted to cocaine, NAC does not appear to modulate glutamate neurotransmission in healthy adult humans. NAC has been hypothesized to exert beneficial effects through its modulation of glutamate and dopamine neurotransmission as well as its antioxidant properties.
Microbiological use
Acetylcysteine can be used in Petroffs method of liquefaction and decontamination of sputum, in preparation for recovery of mycobacterium. It also displays significant antiviral activity against the influenza A viruses.Acetylcysteine has bactericidal properties and breaks down bacterial biofilms of clinically relevant pathogens including Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Enterobacter cloacae, Staphylococcus epidermidis, and Klebsiella pneumoniae.
Other uses
Acetylcysteine has been used to complex palladium, to help it dissolve in water. This helps to remove palladium from drugs or precursors synthesized by palladium-catalyzed coupling reactions. N-actelylcysteine can be used to protect the liver.
Side effects
The most commonly reported adverse effects for IV formulations of acetylcysteine are rash, urticaria, and itchiness. Up to 18% of patients have been reported to experience anaphylaxis reaction, which are defined as rash,
hypotension, wheezing, and/or shortness of breath. Lower rates of anaphylactoid reactions have been reported with slower rates of infusion.
Adverse effects for inhalational formulations of acetylcysteine include nausea, vomiting, stomatitis, fever, rhinorrhea, drowsiness, clamminess, chest tightness, and bronchoconstriction. Although infrequent, bronchospasm has been reported to occur unpredictably in some patients.Adverse effects for oral formulations of acetylcysteine have been reported to include nausea, vomiting, rash, and fever.Large doses in a mouse model showed that acetylcysteine could potentially cause damage to the heart and lungs. They found that acetylcysteine was metabolized to S-nitroso-N-acetylcysteine (SNOAC), which increased blood pressure in the lungs and right ventricle of the heart (pulmonary artery hypertension) in mice treated with acetylcysteine. The effect was similar to that observed following a 3-week exposure to an oxygen-deprived environment (chronic hypoxia). The authors also found that SNOAC induced a hypoxia-like response in the expression of several important genes both in vitro and in vivo.
The implications of these findings for long-term treatment with acetylcysteine have not yet been investigated. The dose used by Palmer and colleagues was dramatically higher than that used in humans, the equivalent of about 20 grams per day. Nonetheless, positive effects on age-diminished control of respiration (the hypoxic ventilatory response) have been observed previously in human subjects at more moderate doses.Although N-acetylcysteine prevented liver damage in mice when taken before alcohol, when taken four hours after alcohol it made liver damage worse in a dose-dependent fashion.
Pharmacology
Pharmacodynamics
Acetylcysteine serves as a prodrug to L-cysteine, a precursor to the biologic antioxidant glutathione. Hence administration of acetylcysteine replenishes glutathione stores.
Glutathione, along with oxidized glutathione (GSSG) and S-nitrosoglutathione (GSNO), have been found to bind to the glutamate recognition site of the NMDA and AMPA receptors (via their γ-glutamyl moieties), and may be endogenous neuromodulators. At millimolar concentrations, they may also modulate the redox state of the NMDA receptor complex. In addition, glutathione has been found to bind to and activate ionotropic receptors that are different from any other excitatory amino acid receptor, and which may constitute glutathione receptors, potentially making it a neurotransmitter. As such, since N-acetylcysteine is a prodrug of glutathione, it may modulate all of the aforementioned receptors as well.
Glutathione also modulates the NMDA receptor by acting at the redox site.L-cysteine also serves as a precursor to cystine, which in turn serves as a substrate for the cystine-glutamate antiporter on astrocytes; hence there is increasing glutamate release into the extracellular space. This glutamate in turn acts on mGluR2/3 receptors, and at higher doses of acetylcysteine, mGluR5.Acetylcysteine also possesses some anti-inflammatory effects possibly via inhibiting NF-κB and modulating cytokine synthesis.
Pharmacokinetics
Acetylcysteine is extensively liver metabolized, CYP450 minimal, urine excretion is 22–30% with a half-life of 5.6 hours in adults and 11 hours in newborns.
Chemistry
Acetylcysteine is the N-acetyl derivative of the amino acid L-cysteine, and is a precursor in the formation of the antioxidant glutathione in the body. The thiol (sulfhydryl) group confers antioxidant effects and is able to reduce free radicals.
N-acetyl-L-cysteine is soluble in water and alcohol, and practically insoluble in chloroform and ether.It is a white to white with light yellow cast powder, and has a pKa of 9.5 at 30 °C.
Dosage forms
Acetylcysteine is available in different dosage forms for different indications:
Solution for inhalation (Assist, Mucomyst, Mucosil) – inhaled for mucolytic therapy
Intravenous injection (Assist, Parvolex, Acetadote) – treatment of paracetamol/acetaminophen overdose
Nebulized as an inhaled vapor, particularly in the treatment of cystic fibrosis and other acute pulmonary conditions
Oral solution – various indications
Effervescent tablets
Ocular solution – for mucolytic therapy
Tablets – sometimes in a sustained release formula sold as a nutritional supplement
CapsulesThe IV injection and inhalation preparations are, in general, prescription only, whereas the oral solution and the effervescent tablets are available over the counter in many countries. Acetylcysteine is available as a health supplement in the United States, typically in capsule form.
Society and culture
NAC was first studied as a drug in 1963. Amazon removed NAC for sale in the US in 2021, due to claims by the FDA of it being classified as a drug rather than a supplement. As of 21 April 2022, the FDA released draft guidance on FDAs policy regarding products labeled as dietary supplements that contain N-acetyl-L-cysteine.NAC was studied as a drug and is today used as a medicine. It has also been sold as a dietary supplement within the United States prior to the advent of the Dietary Supplement Health Education Act (DSHEA 1994). The American Herbal Products Association (AHPA) and others have provided the FDA with details regarding NAC products sold before 15 October 1994. Additionally, NAC itself is found in a variety of foods (garlic, onions, asparagus, and others).In 2020 FDA sent warning letters to several companies regarding the use of NAC in dietary supplements. In those letters FDA noted that NAC could not be marketed as a dietary supplement because NAC had NOT been marketed as a food or dietary supplement prior to its approval as a drug. FDA had confirmed in response to two citizen petitions (CRN and NPA) that NAC is excluded from the definition of a dietary supplement. FDA had not yet reached a decision, however, regarding a petitioners (NPA) request to issue a regulation that would permit the use of NAC in dietary supplements. On April 21, 2022, the FDA announced the availability of a draft guidance on FDAs policy regarding products labeled as dietary supplements that contain N-acetyl-L-cysteine. The draft guidance, when finalized, will explain the agencys intent to exercise enforcement discretion with respect to the sale and distribution of certain NAC-containing products that are labeled as dietary supplements. The FDA has asked for comments on its NAC Guidance and has stated that they will use enforcement discretion with respect to NAC supplements.
Research
While many antioxidants have been researched to treat a large number of diseases by reducing the negative effect of oxidative stress, acetylcysteine is one of the few that has yielded promising results, and is currently already approved for the treatment of paracetamol overdose.
In mouse mdx models of Duchennes muscular dystrophy, treatment with 1–2% acetylcysteine in drinking water significantly reduces muscle damage and improves strength.
It is being studied in conditions such as autism, where cysteine and related sulfur amino acids may be depleted due to multifactorial dysfunction of methylation pathways involved in methionine catabolism.
Animal studies have also demonstrated its efficacy in reducing the damage associated with moderate traumatic brain or spinal injury, and also ischaemia-induced brain injury. In particular, it has been demonstrated to reduce neuronal losses and to improve cognitive and neurological outcomes associated with these traumatic events.
It has been suggested that acetylcysteine may help people with Samters triad by increasing levels of glutathione allowing faster breakdown of salicylates, although there is no evidence that it is of benefit.
Small studies have shown acetylcysteine to be of benefit to people with blepharitis. It has been shown to reduce ocular soreness caused by Sjögrens syndrome.
It has been shown that N-acetylcysteine may protect the human cochlea from subclinical hearing loss caused by loud noises such as impulse noise. In animal models, it reduced age-related hearing loss.
It has been shown effective in the treatment of Unverricht-Lundborg disease in an open trial in four patients. A marked decrease in myoclonus and some normalization of somatosensory evoked potentials with acetylcysteine treatment has been documented.
Addiction to certain addictive drugs (including cocaine, heroin, alcohol, and nicotine) is correlated with a persistent reduction in the expression of excitatory amino acid transporter 2 (EAAT2) in the nucleus accumbens (NAcc); the reduced expression of EAAT2 in this region is implicated in addictive drug-seeking behavior. In particular, the long-term dysregulation of glutamate neurotransmission in the NAcc of addicts is associated with an increase in vulnerability to relapse after re-exposure to the addictive drug or its associated drug cues. Drugs that help to normalize the expression of EAAT2 in this region, such as N-acetylcysteine, have been proposed as an adjunct therapy for the treatment of addiction to cocaine, nicotine, alcohol, and other drugs.
It is being tested for the reduction of hangover symptoms, but the clinical trial results are still being evaluated.
A double-blind placebo controlled trial of 262 patients has shown NAC treatment was well-tolerated and resulted in a significant decrease in the frequency of influenza-like episodes, severity, and length of time confined to bed.
COVID-19
NAC is being considered as a possible treatment for COVID-19.
References
External links
"Acetylcysteine". Drug Information Portal. U.S. National Library of Medicine. |
Setmelanotide | Setmelanotide, sold under the brand name Imcivree, is a medication used for the treatment of genetic obesity caused by a rare single-gene mutation.The most common side effects include injection site reactions, skin hyperpigmentation (skin patches that are darker than surrounding skin), headache and gastrointestinal side effects (such as nausea, diarrhea, and abdominal pain), among others. Spontaneous penile erections in males and adverse sexual reactions in females have occurred with treatment. Depression and suicidal ideation have also occurred with setmelanotide.Setmelanotide was approved for medical use in the United States in November 2020, and in the European Union in July 2021. The U.S. Food and Drug Administration (FDA) considers it to be a first-in-class medication.
Medical uses
Setmelanotide is indicated for chronic weight management (weight loss and weight maintenance for at least one year) in people six years and older with obesity due to three rare genetic conditions: pro-opiomelanocortin (POMC) deficiency, proprotein subtilisin/kexin type 1 (PCSK1) deficiency, and leptin receptor (LEPR) deficiency confirmed by genetic testing demonstrating variants in POMC, PCSK1, or LEPR genes considered pathogenic (causing disease), likely pathogenic, or of uncertain significance. Setmelanotide is the first FDA-approved treatment for these genetic conditions.Setmelanotide is not approved for obesity due to suspected POMC, PCSK1, or LEPR deficiency with variants classified as benign (not causing disease) or likely benign or other types of obesity, including obesity associated with other genetic syndromes and general (polygenic) obesity.
Pharmacology
Setmelanotide binds to and activates MC4 receptors in the paraventricular nucleus (PVN) of the hypothalamus and in the lateral hypothalamic area (LHA), areas involved in the regulation of appetite, and this action is thought to underlie its appetite suppressant effects. In addition to reducing appetite, setmelanotide increases resting energy expenditure in both obese animals and humans. Importantly, unlike certain other MC4 receptor agonists, such as LY-2112688, setmelanotide has not been found to produce increases in heart rate or blood pressure.Setmelanotide has been reported to possess the following activity profile (cAMP, EC50): MC4 (0.27 nM) > MC3 (5.3 nM) ≈ MC1 (5.8 nM) > MC5 (1600 nM) ≟ MC2 (>1000 nM). (19.6-fold selectivity for MC4 over MC3, the second target of highest activity.)
History
Setmelanotide was invented at Ipsen by Jesse Z. Dong. It was initially known as BIM-22493 and then as RM-493 and IRC-022493.
It was evaluated in two one-year clinical studies. The first study enrolled 10 participants with obesity and confirmed or suspected POMC or PCSK1 deficiency while the second study enrolled 11 participants with obesity and confirmed or suspected LEPR deficiency; all participants were six years or older. Most participants had lost more than 10% of their initial body weight after a year of treatment. Some participants also reported feeling less hungry.The U.S. Food and Drug Administration (FDA) granted the application for setmelanotide orphan disease designation, breakthrough therapy designation, and priority review. The FDA granted the approval of Imcivree to Rhythm Pharmaceutical, Inc.
Society and culture
Legal status
Setmelanotide was approved for medical use in the United States in November 2020.Setmelanotide was approved for medical use in the European Union in July 2021.
Research
Setmelanotide is a peptide drug and investigational anti-obesity medication which acts as a selective agonist of the MC4 receptor; the structure of the bound complex has recently been determined. Its peptide sequence is Ac-Arg-Cys(1)-D-Ala-His-D-Phe-Arg-Trp-Cys(1)-NH2. It was first discovered at Ipsen and is being developed by Rhythm Pharmaceuticals for the treatment of obesity and diabetes. In addition, Rhythm Pharmaceuticals is conducting trials of setmelanotide for the treatment of Prader–Willi syndrome (PWS), a genetic disorder which includes MC4 receptor deficiency and associated symptoms such as excessive appetite and obesity. As of December 2014, the drug is in phase II clinical trials for obesity and PWS. So far, preliminary data has shown no benefit of Setmelanotide in Prader-Willi syndrome.
References
External links
"Setmelanotide". Drug Information Portal. U.S. National Library of Medicine.
Clinical trial number NCT02896192 for "Setmelanotide for the Treatment of Early-Onset POMC Deficiency Obesity" at ClinicalTrials.gov
Clinical trial number NCT03287960 for "Setmelanotide for the Treatment of LEPR Deficiency Obesity" at ClinicalTrials.gov |
Prax | Prax may refer to:
Prax (malware), or Regin, a malware and hacking toolkit
Prax Group, operators of Lindsey Oil Refinery, North Killingholme, North Lincolnshire, England
Praso, Italy (German: Prax), a former comune in Trentino, Italy
Mike Prax (born 1956), American politician from Alaska
Valentine Prax (1897–1981), French expressionist and cubist painter |
Rilonacept | Rilonacept, sold under the brand name Arcalyst, is a medication used to treat cryopyrin-associated periodic syndromes, including familial cold autoinflammatory syndrome, and Muckle–Wells syndrome; deficiency of interleukin-1 receptor antagonist; and recurrent pericarditis. Rilonacept is an interleukin 1 inhibitor.Rilonacept is a dimeric fusion protein consisting of the ligand-binding domains of the extracellular portions of the human interleukin-1 receptor component (IL-1R1) and IL-1 receptor accessory protein (IL-1RAcP) linked in-line to the fragment-crystallizable portion (Fc region) of human IgG1 that binds and neutralizes IL-1.Rilonacept was given an orphan drug designation by the U.S. Food and Drug Administration (FDA) and is used for the treatment of cryopyrin-associated periodic syndromes (CAPS), including familial cold autoinflammatory syndrome, Muckle–Wells syndrome. Rilonacept is the first drug approved by the FDA to treat recurrent pericarditis. Rilonacept was approved for medical use in the United States in February 2008.On May 8, 2012, an FDA Advisory Panel voted 11–0 against the approval of rilonacept for the treatment of gout, stating that the benefits did not outweigh the risks associated with the drug.
References
External links
"Rilonacept". Drug Information Portal. U.S. National Library of Medicine. |
Mefenamic acid | Mefenamic acid is a member of the anthranilic acid derivatives (or fenamate) class of nonsteroidal anti-inflammatory drugs (NSAIDs), and is used to treat mild to moderate pain.Its name derives from its systematic name, dimethylphenylaminobenzoic acid. It was discovered and brought to market by Parke-Davis in the 1960s. It became generic in the 1980s and is available worldwide under many brand names such as Meftal.
Medical uses
Mefenamic acid is used to treat pain and inflammation in rheumatoid arthritis and osteoarthritis, postoperative pain, acute pain including muscle and back pain, toothache and menstrual pain, as well as being prescribed for menorrhagia.There is evidence that supports the use of mefenamic acid for perimenstrual migraine headache prophylaxis, with treatment starting two days prior to the onset of flow or one day prior to the expected onset of the headache and continuing for the duration of menstruation.Mefenamic acid is recommended to be taken with food.
Contraindications
Mefenamic acid is contraindicated in people who have shown hypersensitivity reactions such as urticaria and asthma to this drug or to other NSAIDs (e.g. aspirin); those with peptic ulcers or chronic inflammation of the gastrointestinal tract; those with kidney or liver disease; heart failure; after coronary artery bypass surgery; and during the third trimester of pregnancy.
Side effects
Known mild side effects of mefenamic acid include headaches, nervousness, and vomiting. Potentially serious side effects may include diarrhea, gastrointestinal perforation, peptic ulcers, hematemesis (vomiting blood), skin reactions (rashes, itching, swelling; in rare cases toxic epidermal necrolysis) and rarely blood cell disorders such as agranulocytosis.: 334 It has been associated with acute liver damage.In 2008 the US label was updated with a warning concerning a risk of premature closure of the ductus arteriosus in pregnancy.In October 2020, the U.S. Food and Drug Administration (FDA) required the drug label to be updated for all nonsteroidal anti-inflammatory medications to describe the risk of kidney problems in unborn babies that result in low amniotic fluid. They recommend avoiding NSAIDs in pregnant women at 20 weeks or later in pregnancy.
Overdose
Symptoms of overdosing include kidney failure, gastrointestinal problems, bleeding, rashes, confusion, hallucinations, vertigo, seizures, and loss of consciousness. It is treated with induction of vomiting, gastric lavage, bone char, and control of electrolytes and vital functions.
Interactions
Interactions are broadly similar to those of other NSAIDs. Mefenamic acid interferes with the anti–blood clotting mechanism of Aspirin. It increases the blood thinning effects of warfarin and phenprocoumon because it displaces them from their plasma protein binding and increases their free concentrations in the bloodstream. It adds to the risk of gastrointestinal ulcera associated with corticosteroids and selective serotonin reuptake inhibitors. It can increase the risk for adverse effects of methotrexate and lithium by lowering their excretion via the kidneys. It can increase the kidney toxicity of ciclosporin and tacrolimus. Combination with antihypertensive drugs such as ACE inhibitors, sartans and diuretics can decrease their effectiveness as well as increase the risk for kidney toxicity.
Pharmacology
Mechanism of action
Like other members of the anthranilic acid derivatives (or fenamate) class of NSAIDs, it inhibits both isoforms of the enzyme cyclooxygenase (COX-1 and COX-2). This prevents formation of prostaglandins, which play a role in pain sensitivity, inflammation and fever, but also in hemostasis, kidney function, sustaining of pregnancy, and protection of the gastric mucosa.
Pharmacokinetics
Mefenamic acid is rapidly absorbed from the gut and reaches highest concentrations in the blood plasma after one to four hours. When in the bloodstream, over 90% of the substance are bound to plasma proteins. It probably crosses the placenta, and is found in the breast milk in small amounts.It is metabolized by the liver enzyme CYP2C9 to the only weakly active 3-hydroxymethylmefenamic acid. 3-carboxymefenamic acid has also been identified as a metabolite, as well as carboxy glucuronides of all three substances. Mefenamic acid and its metabolites are excreted via the urine (52–67%) and the faeces (20–25%, or less than 20% following another source). The parent substance has a biological half-life of two hours; the half-life of its metabolites may be longer.
History
Scientists led by Claude Winder from Parke-Davis invented mefenamic acid in 1961, along with fellow members of the class of anthranilic acid derivatives, flufenamic acid in 1963 and meclofenamate sodium in 1964.: 718 U.S. Patent 3,138,636 on the drug was issued in 1964.: 918–919 It was approved in the UK in 1963 as Ponstan, in West Germany in 1964 as Ponalar and in France as Ponstyl, and the US in 1967 as Ponstel.: 918–919
Chemistry
Synthesis
Analogous to fenamic acid, this compound may be made from 2-chlorobenzoic acid and 2,3-dimethylaniline.
Society and culture
Availability and pricing
Mefenamic acid is generic and is available worldwide under many brand names.In the US, wholesale price of a weeks supply of generic mefenamic acid has been quoted as $426.90 in 2014. Brand-name Ponstel is $571.70. In contrast, in the UK, a weeks supply is £1.66, or £8.17 for branded Ponstan.
Research
While studies have been conducted to see if mefenamic acid can improve behavior in transgenic mouse models of Alzheimers disease there is little evidence that mefenamic acid or other NSAIDs can treat or prevent Alzheimers in humans; clinical trials of NSAIDs other than mefenamic acid for treatment of Alzheimers have found more harm than benefit.A small controlled study of 28 human subjects showed improved cognitive impairment using mefenamic acid non-steroidal anti-inflammatory therapy.
See also
Niflumic acid
References
Sources
MedlinePlus Drug Information: Mefenamic Acid. Last accessed September 28, 2005.
Ponstel Pharmacology, Pharmacokinetics, Studies, Metabolism - Mefenamic Acid - RxList Monographs. Last accessed September 28, 2005.
Consumption of NSAIDs and the Development of Congestive Heart Failure in Elderly Patients
NSAIDs May Increase Risk for Worsening Heart Failure |
Immunoglobulin therapy | Immunoglobulin therapy is the use of a mixture of antibodies (normal human immunoglobulin or NHIG) to treat a number of health conditions. These conditions include primary immunodeficiency, immune thrombocytopenic purpura, chronic inflammatory demyelinating polyneuropathy, Kawasaki disease, certain cases of HIV/AIDS and measles, Guillain-Barré syndrome, and certain other infections when a more specific immunoglobulin is not available. Depending on the formulation it can be given by injection into muscle, a vein, or under the skin. The effects last a few weeks.Common side effects include pain at the site of injection, muscle pain, and allergic reactions. Other severe side effects include kidney problems, anaphylaxis, blood clots, and red blood cell breakdown. Use is not recommended in people with some types of IgA deficiency. Use appears to be relatively safe during pregnancy. Human immunoglobulin is made from human blood plasma. It contains antibodies against many viruses.Human immunoglobulin therapy first occurred in the 1930s and a formulation for injection into a vein was approved for medical use in the United States in 1981. It is on the World Health Organizations List of Essential Medicines. Each formulation of product is somewhat different. A number of specific immunoglobulin formulations are also available including for hepatitis B, rabies, tetanus, varicella infection, and Rh positive blood exposure.
Medical uses
Immunoglobulin therapy is used in a variety of conditions, many of which involve decreased or abolished antibody production capabilities, which range from a complete absence of multiple types of antibodies, to IgG subclass deficiencies (usually involving IgG2 or IgG3), to other disorders in which antibodies are within a normal quantitative range, but lacking in quality – unable to respond to antigens as they normally should – resulting in an increased rate or increased severity of infections. In these situations, immunoglobulin infusions confer passive resistance to infection on their recipients by increasing the quantity/quality of IgG they possess. Immunoglobulin therapy is also used for a number of other conditions, including in many autoimmune disorders such as dermatomyositis in an attempt to decrease the severity of symptoms. Immunoglobulin therapy is also used in some treatment protocols for secondary immunodeficiencies such as human immunodeficiency virus (HIV), some autoimmune disorders (such as immune thrombocytopenia and Kawasaki disease), some neurological diseases (multifocal motor neuropathy, stiff person syndrome, multiple sclerosis and myasthenia gravis) some acute infections and some complications of organ transplantation.Immunoglobulin therapy is especially useful in some acute infection cases such as pediatric HIV infection and is also considered the standard of treatment for some autoimmune disorders such as Guillain–Barré syndrome. The high demand which coupled with the difficulty of producing immunoglobulin in large quantities has resulted in increasing global shortages, usage limitations and rationing of immunoglobulin.
United Kingdom
The United Kingdoms National Health Service recommends the routine use of immunoglobulin for a variety of conditions including primary immunodeficiencies and a number of other conditions, but recommends against the use of immunoglobulin in sepsis (unless a specific toxin has been identified), multiple sclerosis, neonatal sepsis, and pediatric HIV/AIDS.
United States
The American Academy of Allergy, Asthma, and Immunology supports the use of immunoglobulin for primary immunodeficiencies, while noting that such usage actually accounts for a minority of usage and acknowledging that immunoglobulin supplementation can be appropriately used for a number of other conditions, including neonatal sepsis (citing a sixfold decrease in mortality), considered in cases of HIV (including pediatric HIV), considered as a second line treatment in relapsing-remitting multiple sclerosis, but recommending against its use in such conditions as chronic fatigue syndrome, PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection) until further evidence to support its use is found (though noting that it may be useful in PANDAS patients with an autoimmune component), cystic fibrosis, and a number of other conditions.Brands include
Asceniv (immune globulin intravenous, human – slra)
Bivigam (immune globulin intravenous – human 10% liquid)
Gamunex-C, (immune globulin injection human)
Hizentra (immune globulin subcutaneous human)
Hyqvia (immune globulin 10 percent – human with recombinant human hyaluronidase)
Octagam (immune globulin intravenous, human)
Panzyga (immune globulin intravenous, human – ifas)
Xembify (immune globulin subcutaneous, human – klhw)
Canada
The National Advisory Committee on Blood and Blood Products of Canada (NAC) and Canadian Blood Services have also developed their own separate set of guidelines for the appropriate use of immunoglobulin therapy, which strongly support the use of immunoglobulin therapy in primary immunodeficiencies and some complications of HIV, while remaining silent on the issues of sepsis, multiple sclerosis, and chronic fatigue syndrome.
Australia
The Australian Red Cross Blood Service developed their own guidelines for the appropriate use of immunoglobulin therapy in 1997. Immunoglobulin is funded under the National Blood Supply and indications are classified as either an established or emerging therapeutic role or conditions for which immunoglobulin use is in exceptional circumstances only.Subcutaneous immunoglobulin access programs have been developed to facilitate hospital based programs.Human normal immunoglobulin (human immunoglobulin G) (Cutaquig) was approved for medical use in Australia in May 2021.
European Union
Brands include HyQvia (human normal immunoglobulin), Privigen (human normal immunoglobulin (IVIg)), Hizentra (human normal immunoglobulin (SCIg)), Kiovig (human normal immunoglobulin), and Flebogamma DIF (human normal immunoglobulin).In the EU human normal immunoglobulin (SCIg) (Hizentra) is used in people whose blood does not contain enough antibodies (proteins that help the body to fight infections and other diseases), also known as immunoglobulins. It is used to treat the following conditions:
primary immunodeficiency syndromes (PID, when people are born with an inability to produce enough antibodies);
low levels of antibodies in the blood in people with chronic lymphocytic leukaemia (a cancer of a type of white blood cell) or myeloma (a cancer of another type of white blood cell) and who have frequent infections;
low levels of antibodies in the blood in people before or after allogeneic haematopoietic stem cell transplantation (a procedure where the patients bone marrow is cleared of cells and replaced by stem cells from a donor);
chronic inflammatory demyelinating polyneuropathy (CIDP). In this rare disease, the immune system (the bodys defence system) works abnormally and destroys the protective covering over the nerves.It is indicated for replacement therapy in adults and children in primary immunodeficiency syndromes such as:
congenital agammaglobulinaemia and hypogammaglobulinaemia (low levels of antibodies);
common variable immunodeficiency;
severe combined immunodeficiency;
immunoglobulin-G-subclass deficiencies with recurrent infections;
replacement therapy in myeloma or chronic lymphocytic leukaemia with severe secondary hypogammaglobulinaemia and recurrent infections.Flebogamma DIF is indicated for the replacement therapy in adults, children and adolescents (0–18 years) in:
primary immunodeficiency syndromes with impaired antibody production;
hypogammaglobulinaemia (low levels of antibodies) and recurrent bacterial infections in patients with chronic lymphocytic leukaemia (a cancer of a type of white blood cell), in whom prophylactic antibiotics have failed;
hypogammaglobulinaemia (low levels of antibodies) and recurrent bacterial infections in plateau-phase-multiple-myeloma (another cancer of a type of white blood cell) patients who failed to respond to pneumococcal immunisation;
hypogammaglobulinaemia (low levels of antibodies) in patients after allogenic haematopoietic-stem-cell transplantation (HSCT) (when the patient receives stem cells from a matched donor to help restore the bone marrow);
congenital acquired immune deficiency syndrome (AIDS) with recurrent bacterial infections.and for the immunomodulation in adults, children and adolescents (0–18 years) in:
primary immune thrombocytopenia (ITP), in patients at high risk of bleeding or prior to surgery to correct the platelet count;
Guillain–Barré syndrome, which causes multiple inflammations of the nerves in the body;
Kawasaki disease, which causes multiple inflammation of several organs in the body.
Side effects
Although immunoglobulin is frequently used for long periods of time and is generally considered safe, immunoglobulin therapy can have severe adverse effects, both localized and systemic. Subcutaneous administration of immunoglobulin is associated with a lower risk of both systemic and localized risk when compared to intravenous administration (hyaluronidase-assisted subcutaneous administration is associated with a greater frequency of adverse effects than traditional subcutaneous administration but still a lower frequency of adverse effects when compared to intravenous administration). Patients who are receiving immunoglobulin and experience adverse events are sometimes recommended to take acetaminophen and diphenhydramine before their infusions to reduce the rate of adverse effects. Additional premedication may be required in some instances (especially when first getting accustomed to a new dosage), prednisone or another oral steroid.Local side effects of immunoglobulin infusions most frequently include an injection site reaction (reddening of the skin around the injection site), itching, rash, and hives. Less serious systemic side effects to immunoglobulin infusions include an increased heart rate, hyper or hypotension, an increased body temperature, diarrhea, nausea, abdominal pain, vomiting, arthralgia or myalgia, dizziness, headache, fatigue, fever, and pain.Serious side effects of immunoglobulin infusions include chest discomfort or pain, myocardial infarction, tachycardia, hyponatremia, hemolysis, hemolytic anemia, thrombosis, hepatitis, anaphylaxis, backache, aseptic meningitis, acute kidney injury, hypokalemic nephropathy, pulmonary embolism, and transfusion related acute lung injury. There is also a small chance that even given the precautions taken in preparing immunoglobulin preparations, an immunoglobulin infusion may pass a virus to its recipient. Some immunoglobulin solutions also contain isohemagglutinins, which in rare circumstances can cause hemolysis by the isohemagglutinins triggering phagocytosis.In the case of less serious side effects, a patients infusion rate can be adjusted downwards until the side effects become tolerable, while in the case of more serious side effects, emergency medical attention should be sought.Immunoglobulin therapy also interferes with the ability of the body to produce a normal immune response to an attenuated live virus vaccine for up to a year, can result in falsely elevated blood glucose levels, and can interfere with many of the IgG-based assays often used to diagnose a patient with a particular infection.
Routes of administration
1950s – intramuscular
After immunoglobulin therapys discovery and description in Pediatrics in 1952, weekly intramuscular injections of immunoglobulin (IMIg) were the norm until intravenous formulations (IVIg) began to be introduced in the 1980s. During the mid and late 1950s, one-time IMIg injections were a common public health response to outbreaks of polio before the widespread availability of vaccines. Intramuscular injections were extremely poorly tolerated due to their extreme pain and poor efficacy – rarely could intramuscular injections alone raise plasma immunoglobulin levels enough to make a clinically meaningful difference.
1980s – intravenous
Intravenous formulations began to be approved in the 1980s, which represented a significant improvement over intramuscular injections, as they allowed for a sufficient amount of immunoglobulin to be injected to reach clinical efficacy, although they still had a fairly high rate of adverse effects (though the addition of stabilizing agents reduced this further).
1990s – subcutaneous
The first description of a subcutaneous route of administration for immunoglobulin therapy dates back to 1980, but for many years subcutaneous administration was considered to be a secondary choice, only to be considered when peripheral venous access was no longer possible or tolerable.During the late 1980s and early 1990s, it became obvious that for at least a subset of patients the systemic adverse events associated with intravenous therapy were still not easily tolerable, and more doctors began to experiment with subcutaneous immunoglobulin administration, culminating in an ad hoc clinical trial in Sweden of 3000 subcutaneous injections administered to 25 adults (most of whom had previously experienced systemic adverse effects with IMIg or IVIg), where no infusion in the ad hoc trial resulted in a severe systemic adverse reaction, and most subcutaneous injections were able to be administered in non-hospital settings, allowing for considerably more freedom for the people involved.In the later 1990s, large-scale trials began in Europe to test the feasibility of subcutaneous immunoglobulin administration, although it was not until 2006 that the first subcutaneous-specific preparation of immunoglobulin was approved by a major regulatory agency (Vivaglobin, which was voluntarily discontinued in 2011). A number of other trade names of subcutaneous immunoglobulin have since been approved, although some small-scale studies have indicated that a particular cohort of patients with common variable immunodeficiency (CVID) may develop intolerable side effects with subcutaneous immunoglobulin (SCIg) that they do not with intravenous immunoglobulin (IVIg).Although intravenous was the preferred route for immunoglobulin therapy for many years, in 2006, the US Food and Drug Administration (FDA) approved the first preparation of immunoglobulin that was designed exclusively for subcutaneous use.
Mechanism of action
The precise mechanism by which immunoglobulin therapy suppresses harmful inflammation is likely multifactorial. For example, it has been reported that immunoglobulin therapy can block Fas-mediated cell death.Perhaps a more popular theory is that the immunosuppressive effects of immunoglobulin therapy are mediated through IgGs Fc glycosylation. By binding to receptors on antigen presenting cells, IVIG can increase the expression of the inhibitory Fc receptor, FcgRIIB, and shorten the half-life of auto-reactive antibodies. The ability of immunoglobulin therapy to suppress pathogenic immune responses by this mechanism is dependent on the presence of a sialylated glycan at position CH2-84.4 of IgG. Specifically, de-sialylated preparations of immunoglobulin lose their therapeutic activity and the anti-inflammatory effects of IVIG can be recapitulated by administration of recombinant sialylated IgG1 Fc.Sialylated-Fc-dependent mechanism was not reproduced in other experimental models suggesting that this mechanism is functional under a particular disease or experimental settings. On the other hand, several other mechanisms of action and the actual primary targets of immunoglobulin therapy have been reported. In particular, F(ab)2-dependent action of immunoglobulin to inhibit activation of human dendritic cells, induction of autophagy, induction of COX-2-dependent PGE-2 in human dendritic cells leading to expansion of regulatory T cells, inhibition of pathogenic Th17 responses, and induction of human basophil activation and IL-4 induction via anti-IgE autoantibodies. Some believe that immunoglobulin therapy may work via a multi-step model where the injected immunoglobulin first forms a type of immune complex in the patient. Once these immune complexes are formed, they can interact with Fc receptors on dendritic cells, which then mediate anti-inflammatory effects helping to reduce the severity of the autoimmune disease or inflammatory state.
Other proposed mechanisms include the possibility that donor antibodies may bind directly with the abnormal host antibodies, stimulating their removal; the possibility that IgG stimulates the hosts complement system, leading to enhanced removal of all antibodies, including the harmful ones; and the ability of immunoglobulin to block the antibody receptors on immune cells (macrophages), leading to decreased damage by these cells, or regulation of macrophage phagocytosis. Indeed, it is becoming more clear that immunoglobulin can bind to a number of membrane receptors on T cells, B cells, and monocytes that are pertinent to autoreactivity and induction of tolerance to self.A recent report stated that immunoglobulin application to activated T cells leads to their decreased ability to engage microglia. As a result of immunoglobulin treatment of T cells, the findings showed reduced levels of tumor necrosis factor-alpha and interleukin-10 in T cell-microglia co-culture. The results add to the understanding of how immunoglobulin may affect inflammation of the central nervous system in autoimmune inflammatory diseases.
Hyperimmune globulin
Hyperimmune globulins are a class of immunoglobulins prepared in a similar way as for normal human immunoglobulin, except that the donor has high titers of antibody against a specific organism or antigen in their plasma. Some agents against which hyperimmune globulins are available include hepatitis B, rabies, tetanus toxin, varicella-zoster, etc. Administration of hyperimmune globulin provides "passive" immunity to the patient against an agent. This is in contrast to vaccines that provide "active" immunity. However, vaccines take much longer to achieve that purpose while hyperimmune globulin provides instant "passive" short-lived immunity. Hyperimmune globulin may have serious side effects, thus usage is taken very seriously.Hyperimmune serum is blood plasma containing high amounts of an antibody. It has been hypothesised that hyperimmune serum may be an effective therapy for persons infected with the Ebola virus.
Society and culture
Economics
In the United Kingdom a dose cost the NHS between 11.20 and 1,200.00 pounds depending on the type and amount.
Brand names
As biologicals, various trade names of immunoglobulin products are not necessarily interchangeable, and care must be exercised when changing between them. Trade names of intravenous immunoglobulin formulations include Flebogamma, Gamunex, Privigen, Octagam and Gammagard, while trade names of subcutaneous formulations include Cutaquig, Cuvitru, HyQvia, Hizentra, Gamunex-C, and Gammaked.
Supply issues
The United States is one of a handful of countries that allow plasma donors to be paid, meaning that the US supplies much of the plasma-derived medicinal products (including immunoglobulin) used across the world, including more than 50% of the European Unions supply. The Council of Europe has officially endorsed the idea of not paying for plasma donations for both ethical reasons and reasons of safety, but studies have found that relying on entirely voluntary plasma donation leads to shortages of immunoglobulin and forces member countries to import immunoglobulin from countries that do compensate donors.In Australia, blood donation is voluntary and therefore to cope with increasing demand and to reduce the shortages of locally produced immunoglobulin, several programs have been undertaken including adopting plasma for first time blood donors, better processes for donation, plasma donor centres and encouraging current blood donors to consider plasma only donation.
Research
Experimental results from a small clinical trial in humans suggested protection against the progression of Alzheimers disease, but no such benefit was found in a subsequent phase III clinical trial. In May 2020, the US approved a phase three clinical trial on the efficacy and safety of high-concentration intravenous immune globulin therapy in severe COVID-19.
References
External links
"Immune globulin". Drug Information Portal. U.S. National Library of Medicine. |
Atropine | Atropine is a tropane alkaloid and anticholinergic medication used to treat certain types of nerve agent and pesticide poisonings as well as some types of slow heart rate, and to decrease saliva production during surgery. It is typically given intravenously or by injection into a muscle. Eye drops are also available which are used to treat uveitis and early amblyopia. The intravenous solution usually begins working within a minute and lasts half an hour to an hour. Large doses may be required to treat some poisonings.Common side effects include a dry mouth, large pupils, urinary retention, constipation, and a fast heart rate. It should generally not be used in people with angle closure glaucoma. While there is no evidence that its use during pregnancy causes birth defects, that has not been well studied. It is likely safe during breastfeeding. It is an antimuscarinic (a type of anticholinergic) that works by inhibiting the parasympathetic nervous system.Atropine occurs naturally in a number of plants of the nightshade family, including deadly nightshade (belladonna), Jimson weed, and mandrake. It was first isolated in 1833, It is on the World Health Organizations List of Essential Medicines. It is available as a generic medication.
Medical uses
Eyes
Topical atropine is used as a cycloplegic, to temporarily paralyze the accommodation reflex, and as a mydriatic, to dilate the pupils. Atropine degrades slowly, typically wearing off in 7 to 14 days, so it is generally used as a therapeutic mydriatic, whereas tropicamide (a shorter-acting cholinergic antagonist) or phenylephrine (an α-adrenergic agonist) is preferred as an aid to ophthalmic examination.In refractive and accommodative amblyopia, when occlusion is not appropriate sometimes atropine is given to induce blur in the good eye. Evidence suggests that atropine penalization is just as effective as occlusion in improving visual acuity. Antimuscarinic topical medication is effective in slowing myopia progression in children; accommodation difficulties and papillae and follicles are possible side-effects. All doses of atropine appear similarly effective, while higher doses have greater side effects. The lower dose of 0.01% is thus generally recommended due to fewer side effects and potential less rebound worsening when the atropine is stopped.
Heart
Injections of atropine are used in the treatment of symptomatic or unstable bradycardia.
Atropine was previously included in international resuscitation guidelines for use in cardiac arrest associated with asystole and PEA, but was removed from these guidelines in 2010 due to a lack of evidence for its effectiveness. For symptomatic bradycardia, the usual dosage is 0.5 to 1 mg IV push, may repeat every 3 to 5 minutes up to a total dose of 3 mg (maximum 0.04 mg/kg).Atropine is also useful in treating second-degree heart block Mobitz type 1 (Wenckebach block), and also third-degree heart block with a high Purkinje or AV-nodal escape rhythm. It is usually not effective in second-degree heart block Mobitz type 2, and in third-degree heart block with a low Purkinje or ventricular escape rhythm.Atropine has also been used in an effort to prevent a low heart rate during intubation of children; however, evidence does not support this use.
Secretions
Atropines actions on the parasympathetic nervous system inhibit salivary and mucus glands. The drug may also inhibit sweating via the sympathetic nervous system. This can be useful in treating hyperhidrosis, and can prevent the death rattle of dying patients. Even though atropine has not been officially indicated for either of these purposes by the FDA, it has been used by physicians for these purposes.
Poisonings
Atropine is not an actual antidote for organophosphate poisoning. However, by blocking the action of acetylcholine at muscarinic receptors, atropine also serves as a treatment for poisoning by organophosphate insecticides and nerve agents, such as tabun (GA), sarin (GB), soman (GD), and VX. Troops who are likely to be attacked with chemical weapons often carry autoinjectors with atropine and an oxime, for rapid injection into the muscles of the thigh. In a developed case of nerve-gas poisoning, maximum atropinization is desirable. Atropine is often used in conjunction with the oxime pralidoxime chloride.
Some of the nerve agents attack and destroy acetylcholinesterase by phosphorylation, so the action of acetylcholine becomes excessive and prolonged. Pralidoxime (2-PAM) can be effective against organophosphate poisoning because it can re-cleave this phosphorylation. Atropine can be used to reduce the effect of the poisoning by blocking muscarinic acetylcholine receptors, which would otherwise be overstimulated, by excessive acetylcholine accumulation.
Atropine or diphenhydramine can be used to treat muscarine intoxication.
Irinotecan induced diarrhea
Atropine has been observed to prevent or treat irinotecan induced acute diarrhea.
Side effects
Adverse reactions to atropine include ventricular fibrillation, supraventricular or ventricular tachycardia, dizziness, nausea, blurred vision, loss of balance, dilated pupils, photophobia, dry mouth and potentially extreme confusion, deliriant hallucinations, and excitation especially among the elderly. These latter effects are because atropine is able to cross the blood–brain barrier. Because of the hallucinogenic properties, some have used the drug recreationally, though this is potentially dangerous and often unpleasant.In overdoses, atropine is poisonous. Atropine is sometimes added to potentially addictive drugs, particularly antidiarrhea opioid drugs such as diphenoxylate or difenoxin, wherein the secretion-reducing effects of the atropine can also aid the antidiarrhea effects.Although atropine treats bradycardia (slow heart rate) in emergency settings, it can cause paradoxical heart rate slowing when given at very low doses (i.e. <0.5 mg), presumably as a result of central action in the CNS. One proposed mechanism for atropines paradoxical bradycardia effect at low doses involves blockade of inhibitory presynaptic muscarinic autoreceptors, thereby blocking a system that inhibits the parasympathetic response.Atropine is incapacitating at doses of 10 to 20 mg per person. Its LD50 is estimated to be 453 mg per person (by mouth) with a probit slope of 1.8.
The antidote to atropine is physostigmine or pilocarpine.A common mnemonic used to describe the physiologic manifestations of atropine overdose is: "hot as a hare, blind as a bat, dry as a bone, red as a beet, and mad as a hatter". These associations reflect the specific changes of warm, dry skin from decreased sweating, blurry vision, decreased lacrimation, vasodilation, and central nervous system effects on muscarinic receptors, type 4 and 5. This set of symptoms is known as anticholinergic toxidrome, and may also be caused by other drugs with anticholinergic effects, such as hyoscine hydrobromide (scopolamine), diphenhydramine, phenothiazine antipsychotics and benztropine.
Contraindications
It is generally contraindicated in people with glaucoma, pyloric stenosis, or prostatic hypertrophy, except in doses ordinarily used for preanesthesia.
Chemistry
Atropine, a tropane alkaloid, is an enantiomeric mixture of d-hyoscyamine and l-hyoscyamine, with most of its physiological effects due to l-hyoscyamine. Its pharmacological effects are due to binding to muscarinic acetylcholine receptors. It is an antimuscarinic agent. Significant levels are achieved in the CNS within 30 minutes to 1 hour and disappears rapidly from the blood with a half-life of 2 hours. About 60% is excreted unchanged in the urine, most of the rest appears in urine as hydrolysis and conjugation products. Noratropine (24%), atropine-N-oxide (15%), tropine (2%) and tropic acid (3%) appear to be the major metabolites, while 50% of the administered dose is excreted as apparently unchanged atropine. No conjugates were detectable. Evidence that atropine is present as (+)-hyoscyamine was found, suggesting that stereoselective metabolism of atropine probably occurs. Effects on the iris and ciliary muscle may persist for longer than 72 hours.
The most common atropine compound used in medicine is atropine sulfate (monohydrate) (C17H23NO3)2·H2SO4·H2O, the full chemical name is 1α H, 5α H-Tropan-3-α ol (±)-tropate(ester), sulfate monohydrate.
Pharmacology
In general, atropine counters the "rest and digest" activity of glands regulated by the parasympathetic nervous system. This occurs because atropine is a competitive, reversible antagonist of the muscarinic acetylcholine receptors (acetylcholine being the main neurotransmitter used by the parasympathetic nervous system).
Atropine is a competitive antagonist of the muscarinic acetylcholine receptor types M1, M2, M3, M4 and M5. It is classified as an anticholinergic drug (parasympatholytic).
In cardiac uses, it works as a nonselective muscarinic acetylcholinergic antagonist, increasing firing of the sinoatrial node (SA) and conduction through the atrioventricular node (AV) of the heart, opposes the actions of the vagus nerve, blocks acetylcholine receptor sites, and decreases bronchial secretions.
In the eye, atropine induces mydriasis by blocking contraction of the circular pupillary sphincter muscle, which is normally stimulated by acetylcholine release, thereby allowing the radial iris dilator muscle to contract and dilate the pupil. Atropine induces cycloplegia by paralyzing the ciliary muscles, whose action inhibits accommodation to allow accurate refraction in children, helps to relieve pain associated with iridocyclitis, and treats ciliary block (malignant) glaucoma.
The vagus (parasympathetic) nerves that innervate the heart release acetylcholine (ACh) as their primary neurotransmitter. ACh binds to muscarinic receptors (M2) that are found principally on cells comprising the sinoatrial (SA) and atrioventricular (AV) nodes. Muscarinic receptors are coupled to the Gi subunit; therefore, vagal activation decreases cAMP. Gi-protein activation also leads to the activation of KACh channels that increase potassium efflux and hyperpolarizes the cells.
Increases in vagal activities to the SA node decreases the firing rate of the pacemaker cells by decreasing the slope of the pacemaker potential (phase 4 of the action potential); this decreases heart rate (negative chronotropy). The change in phase 4 slope results from alterations in potassium and calcium currents, as well as the slow-inward sodium current that is thought to be responsible for the pacemaker current (If). By hyperpolarizing the cells, vagal activation increases the cells threshold for firing, which contributes to the reduction in the firing rate. Similar electrophysiological effects also occur at the AV node; however, in this tissue, these changes are manifested as a reduction in impulse conduction velocity through the AV node (negative dromotropy). In the resting state, there is a large degree of vagal tone on the heart, which is responsible for low resting heart rates.
There is also some vagal innervation of the atrial muscle, and to a much lesser extent, the ventricular muscle. Vagus activation, therefore, results in modest reductions in atrial contractility (inotropy) and even smaller decreases in ventricular contractility.
Muscarinic receptor antagonists bind to muscarinic receptors thereby preventing ACh from binding to and activating the receptor. By blocking the actions of ACh, muscarinic receptor antagonists very effectively block the effects of vagal nerve activity on the heart. By doing so, they increase heart rate and conduction velocity.
History
The name atropine was coined in the 19th century, when pure extracts from the belladonna plant Atropa belladonna were first made. The medicinal use of preparations from plants in the nightshade family is much older however. Mandragora (mandrake) was described by Theophrastus in the fourth century B.C. for treatment of wounds, gout, and sleeplessness, and as a love potion. By the first century A.D. Dioscorides recognized wine of mandrake as an anaesthetic for treatment of pain or sleeplessness, to be given prior to surgery or cautery. The use of nightshade preparations for anesthesia, often in combination with opium, persisted throughout the Roman and Islamic Empires and continued in Europe until superseded in the 19th century by modern anesthetics.Atropine-rich extracts from the Egyptian henbane plant (another nightshade) were used by Cleopatra in the last century B.C. to dilate the pupils of her eyes, in the hope that she would appear more alluring. Likewise in the Renaissance, women used the juice of the berries of the nightshade Atropa belladonna to enlarge their pupils for cosmetic reasons. This practice resumed briefly in the late nineteenth and early twentieth century in Paris.The pharmacological study of belladonna extracts was begun by the German chemist Friedlieb Ferdinand Runge (1795–1867). In 1831, the German pharmacist Heinrich F. G. Mein (1799-1864) succeeded in preparing a pure crystalline form of the active substance, which was named atropine. The substance was first synthesized by German chemist Richard Willstätter in 1901.
Natural sources
Atropine is found in many members of the family Solanaceae. The most commonly found sources are Atropa belladonna (the deadly nightshade), Datura innoxia, D. wrightii, D. metel, and D. stramonium. Other sources include members of the genera Brugmansia (angels trumpets) and Hyoscyamus.
Synthesis
Atropine can be synthesized by the reaction of tropine with tropic acid in the presence of hydrochloric acid.
Biosynthesis
The biosynthesis of atropine starting from l-phenylalanine first undergoes a transamination forming phenylpyruvic acid which is then reduced to phenyl-lactic acid. Coenzyme A then couples phenyl-lactic acid with tropine forming littorine, which then undergoes a radical rearrangement initiated with a P450 enzyme forming hyoscyamine aldehyde. A dehydrogenase then reduces the aldehyde to a primary alcohol making (−)-hyoscyamine, which upon racemization forms atropine.
Name
The species name "belladonna" (beautiful woman in Italian) comes from the original use of deadly nightshade to dilate the pupils of the eyes for cosmetic effect. Both atropine and the genus name for deadly nightshade derive from Atropos, one of the three Fates who, according to Greek mythology, chose how a person was to die.
See also
Apoatropine
Mark I Nerve Agent Antidote Kit
References
External links
Media related to Atropine at Wikimedia Commons
"Atropine". Drug Information Portal. U.S. National Library of Medicine.
"Atropine sulfate". Drug Information Portal. U.S. National Library of Medicine. |
Cinchocaine | Cinchocaine (INN/BAN) or dibucaine (USAN) is an amide local anesthetic. Among the most potent and toxic of the long-acting local anesthetics, current use of cinchocaine is generally restricted to spinal and topical anesthesia. It is sold under the brand names Cincain, Nupercainal, Nupercaine and Sovcaine.
Medical use
Cinchocaine is the active ingredient in some topical hemorrhoid creams such as Proctosedyl. It is also a component of the veterinary drug Somulose, used for euthanasia of horses and cattle.
Physical properties
Cinchocaine is relatively insoluble in alkaline aqueous solutions.
See also
Dibucaine number
References
Further reading
Abdel-Ghani N, Youssef A, Awady M (2005). "Cinchocaine hydrochloride determination by atomic absorption spectrometry and spectrophotometry". Farmaco. 60 (5): 419–24. doi:10.1016/j.farmac.2005.03.001. PMID 15910814.
Souto-Padron T, Lima AP, de Oliveira Ribeiro R (2006). "Effects of dibucaine on the endocytic/exocytic pathways in Trypanosoma cruzi". Parasitol Res. 99 (4): 317–20. doi:10.1007/s00436-006-0192-1. PMID 16612626. S2CID 5933459.
Nounou M, El-Khordagui L, Khalafallah N (2005). "Effect of various formulation variables on the encapsulation and stability of dibucaine base in multilamellar vesicles". Acta Pol Pharm. 62 (5): 369–79. PMID 16459486.
Aroti, A.; Leontidis, E. (2001). "Simultaneous Determination of the Ionization Constant and the Solubility of Sparingly Soluble Drug Substances. A Physical Chemistry Experiment ". Journal of Chemical Education. 78 (6): 786–788. doi:10.1021/ed078p786. |
Riluzole | Riluzole is a medication used to treat amyotrophic lateral sclerosis and other motor neuron diseases. Riluzole delays the onset of ventilator-dependence or tracheostomy in some people and may increase survival by two to three months. Riluzole is available in tablet and liquid form.
Medical use
Amyotrophic lateral sclerosis
Riluzole was approved in the United States for the treatment of ALS by the U.S. Food and Drug Administration (FDA) in 1995. A Cochrane Library review states a 9% gain in the probability of surviving one year.
Adverse effects
Very common (>10% frequency): nausea; weakness; decreased lung function
Common (1–10% frequency): headache; dizziness; drowsiness; vomiting; abdominal pain; increased aminotransferases
Uncommon (0.1-1% frequency): pancreatitis; interstitial lung disease
Rare (<0.1% frequency): neutropenia; allergic reaction (including angiooedema, anaphylactoid reaction)
Overdose
Symptoms of overdose include: neurological and psychiatric symptoms, acute toxic encephalopathy with stupor, coma and methemoglobinemia. Severe methemoglobinemia may be rapidly reversible after treatment with methylene blue.
Contraindications
Contraindications for riluzole include: known prior hypersensitivity to riluzole or any of the excipients inside the preparations, liver disease, pregnancy or lactation.
Interactions
CYP1A2 substrates, inhibitors and inducers would probably interact with riluzole, due its dependency on this cytochrome for metabolism.
Mechanism of action
Riluzole preferentially blocks TTX-sensitive sodium channels, which are associated with damaged neurons. Riluzole has also been reported to directly inhibit the kainate and NMDA receptors. The drug has also been shown to postsynaptically potentiate GABAA receptors via an allosteric binding site. However, the action of riluzole on glutamate receptors has been controversial, as no binding of the drug to any known sites has been shown for them. In addition, as its antiglutamatergic action is still detectable in the presence of sodium channel blockers, it is also uncertain whether or not it acts via this way. Rather, its ability to stimulate glutamate uptake seems to mediate many of its effects. In addition to its role in accelerating glutamate clearance from the synapse, riluzole may also prevent glutamate release from presynaptic terminals. Since CK1δ plays a key role in TDP-43 proteinopathy, a pathological hallmark of ALS, this could help to better decipher drug mechanism of action.
Synthesis
Riluzole can be prepared beginning with the reaction of 4-(trifluoromethoxy)aniline with potassium thiocyanate followed by reaction with bromine, forming the thiazole ring.
Society and culture
Legal status
Riluzole was approved for medical use in the European Union in October 1996.
Research
A number of case studies have indicated that riluzole may have use in mood and anxiety disorders.A reformulation of riluzole that originated at Yale University and is known by the code name BHV-0223 is under development for the treatment of generalized anxiety disorder and mood disorders by Biohaven Pharmaceuticals.Riluzole, which is neuroprotective and a glutamate modulator could be used for psychiatric problems though it failed in trials of Huntingtons disease and Parkinsons disease.
See also
List of investigational antidepressants
List of investigational anxiolytics
4-Aminopyridine
References
External links
National Institute for Health and Clinical Excellence (NICE) guidelines for prescription of riluzole in the UK
"Riluzole". Drug Information Portal. U.S. National Library of Medicine. |
Sacrosidase | Sacrosidase (trade name Sucraid) is a medication used to replace sucrase in people lacking this enzyme. It is available as an oral solution. Sucraid is approved by the U.S. Food and Drug Administration (FDA) for the therapy of the genetically determined sucrase deficiency that is part of the Congenital Sucrase-Isomaltase Deficiency (CSID). Sacrosidase assists in the breakdown of sugar/sucrose into simpler forms and is useful for the relief of gastrointestinal symptoms that are associated with CSID.
References
External links
Sucraid Oral Solution helps relieve the gastrointestinal symptoms that are associated with CSID (Congenital Sucrase-Isomaltase deficiency). |
Tolnaftate | Tolnaftate (INN) is a synthetic thiocarbamate used as an anti-fungal agent that may be sold without medical prescription in most jurisdictions. It is supplied as a cream, powder, spray, liquid, and liquid aerosol. Tolnaftate is used to treat fungal conditions such as jock itch, athletes foot and ringworm.
Mechanism
Although the exact mechanism of action is not entirely known, it is believed to inhibit squalene epoxidase, an important enzyme in the biosynthetic pathway of ergosterol (a key component of the fungal cell membrane) in a similar way to terbinafine.
Uses
Tolnaftate has been found to be generally slightly less effective than azoles when used to treat tinea pedis (athletes foot). It is, however, useful when dealing with ringworm, especially when passed from pets to humans.
Side effects
Side effects that may occur include:
allergic reactions like:
skin rash
itching or hives
swelling of the face, lips, or tongue
inflammation, redness, or pain at the affected areaLess severe side effects include:
dry skin
mild skin irritation, burning, or itching at the affected area
See also
Liranaftate, a similar thiocarbamate antifungal
References
External links
Medlines entry for tolnaftate |
Lofexidine | Lofexidine, sold under the brand name Lucemyra among others, is a medication historically used to treat high blood pressure; today, it is more commonly used to help with the physical symptoms of opioid withdrawal. It is taken by mouth. It is an α2A adrenergic receptor agonist. It was approved for use by the Food and Drug Administration in the United States in 2018.The U.S. Food and Drug Administration (FDA) considers it to be a first-in-class medication.
Medical uses
In the United States, the brand name Lucemyra (lofexidine HCl) is approved for the "mitigation of withdrawal symptoms to facilitate abrupt discontinuation of opioids in adults," for a treatment duration of 14 days. In the United Kingdom, lofexidine is commonly used in conjunction with the opioid receptor antagonist naltrexone in rapid detoxification cases. When these two drugs are paired, naltrexone is administered to induce an opioid-receptor blockade sending the subject into immediate withdrawal and accelerating the detoxification process, while lofexidine is given to relieve the symptoms associated with the withdrawal including chills, sweating, stomach cramps, muscle pain, and runny nose.
Opioid withdrawal
The United Kingdoms National Institute for Health and Care Excellence (NICE) guidelines recommend the use of methadone or buprenorphine as first-line agents in the management of opioid use disorder. However, lofexidine is considered an acceptable alternative for people with mild or uncertain opioid dependence in need of short-term detoxification.Lofexidine is not an opioid. It does not eliminate the symptoms of opioid withdrawal but reduces them. Indeed, one suggested use for lofexidine is to ease withdrawal symptoms of methadone dependence. Its use is approved in the United States for up to 14 days.
Other clinical uses
The possibility of using lofexidine to treat alcohol withdrawal symptoms has been investigated, and has not yet been shown to be an effective treatment. It is also used in treatment of cases with postmenopausal hot flashes.
Special populations
Lofexidines safety in pregnancy or in the setting of breastfeeding are unknown. Caution is warranted if chronic kidney impairment is present.
Adverse effects
Adverse effects that have occurred after taking lofexidine include the following:
Slow heart rate
Dizziness
Sleepiness
Mouth dryness
Low blood pressure
QT prolongationIn addition, people may experience a sudden jump in blood pressure after stopping lofexidine.
Overdose
The LD50 of lofexidine is above 77 mg/kg in animals. Studies of high-dose, single administrations of lofexidine proved tolerable for animals, but repeat administration induced symptoms consistent with toxicity. In studies on mice, rats, and dogs, these included ataxia, somnolence, and tremors. It is expected that an overdose of lofexidine would result in symptoms akin to its pharmacological side effects in humans, such as bradycardia and hypotension.
Interactions
Many drug-drug interactions with lofexidine are possible.
QT prolongation
Lofexidine prolongs the QT interval, which can result in a severe interaction (torsade de pointes) when combined with other drugs that also prolong the QT interval. Patient-specific characteristics that increase the risk for a clinically significant drug-drug interaction include:
increasing age
female sex
cardiac disease
electrolyte disturbances (low blood potassium)As a result, there are many QT-prolonging drugs that may interact with lofexidine. These include medications such as methadone, amiodarone, citalopram, and fluconazole. Other medications may increase the risk for a low level of potassium in the blood, thereby indirectly increasing the risk for QT prolongation. For example, dexamethasone, hydrochlorothiazide, and theophylline can lower the level of potassium in the blood.
CNS depression
Lofexidine can depress the central nervous system (CNS), which, in combination with other CNS depressants, may reduce a persons ability to perform tasks that require skills and attention. For example, clobazam, gabapentin, and levetiracetam all can depress the CNS.
Hypotension
The risk of hypotension (low blood pressure) is increased when lofexidine is combined with other drugs that lower blood pressure. These may include losartan, metoprolol, and pramipexole.
Pharmacology
Lofexidine is an agonist at the α-2A, 2B, and 2C adrenergic receptor subtypes, with the highest activity at the alpha-2A receptor.
Ki represents the dissociation constant for lofexidines binding to a specific subtype of alpha-2 receptor. The smaller the Ki value, the stronger the drug binds to the receptor to exert its activity.
Lofexidine inhibits the release of norepinephrine in the central and peripheral nervous system, thereby reducing some of the symptoms of opioid withdrawal, but it has no documented effect on drug craving and endogenous opioid levels.
Pharmacokinetics
Lofexidines oral bioavailability is about 90%, with extensive oral absorption. Peak plasma concentrations occur at 3 hours after a single administration, with a half-life of 11 hours. Lofexidine is extensively metabolized by the liver, and primarily cleared by the kidney. It is 80-90% plasma protein bound.
Chemistry
Lofexidine exists as a solid at room temperature, with a melting point of 127 degrees C. The pair of ortho chlorine (Cl−) atoms on the phenyl ring are necessary for lofexidines agonism at the α2a adrenergic receptor subtype; removal of either chlorine atom results in antagonism at the receptor.
Comparison to clonidine
Lofexidine is structurally analogous to clonidine, another α2 adrenergic receptor agonist used for treatment of opioid withdrawal symptoms. A comparison of the two structures is shown at right. Both contain an imidazoline ring and a 2,6-dichlorinated phenyl ring. The differences in structure are shown in red, while the similarities are in black. In addition to the structural differences, administration of lofexidine to people who abuse opioids has been shown to be more effective for a longer duration, with fewer withdrawal symptoms than clonidine even after one day. However, clonidine is often preferred as it is substantially cheaper than lofexidine when purchased with a private (non-NHS) prescription. This factor is exacerbated by the considerable number of and quantities of medications prescribed to alleviate the constellation of withdrawal signs and symptoms. Additionally, clonidine has been shown to significantly lower blood pressure. Therefore, although similar to lofexidine, clonidine is most frequently prescribed to treat high blood pressure.
Society and culture
Britannia Pharmaceuticals has licensed lofexidine to be sold by US WorldMeds for sale in North America. In the United Kingdom, the hydrochloride form, lofexidine HCl, has been licensed and sold since 1992 for opioid withdrawal relief in tablet form as BritLofex by Britannia Pharmaceuticals. BritLofex is only available by prescription. Lofexidine was first approved by the US FDA on May 16, 2018, under the brand name Lucemyra, produced by US WorldMeds. It was noted as the first, non-opioid drug approved in the US for the treatment of opioid withdrawal.
See also
Methadone
Naltrexone
Clonidine
== References == |
Ranolazine | Ranolazine, sold under the brand name Ranexa among others, is a medication used to treat heart related chest pain. Typically it is used together with other medications when those are insufficient. Benefits appear smaller in women than men. It is taken by mouth.Common side effects include constipation, headache, nausea, and dizziness. Serious side effects may include QT prolongation. Use is not recommended in those with liver cirrhosis. How it works is not clear but may involve adenosine triphosphate.Ranolazine was approved for medical use in the United States in 2006. In 2019, it was the 211th most commonly prescribed medication in the United States, with more than 2 million prescriptions.
Medical uses
Ranolazine is used to treat chronic angina. It may be used concomitantly with β blockers, nitrates, calcium channel blockers, antiplatelet therapy, lipid-lowering therapy, ACE inhibitors, and angiotensin receptor blockers. It is also effective at preventing atrial fibrillation, and has been studied as monotherapy as well as in combination with other medications used to treat irregular heartbeat.Its use is not recommended in Scotland as of 2019.
Contraindications
Some contraindications for ranolazine are related to its metabolism and are described under Drug Interactions. Additionally, in clinical trials ranolazine slightly increased QT interval in some patients and the FDA label contains a warning for doctors to beware of this effect in their patients. The drugs effect on the QT interval is increased in the setting of liver dysfunction; thus it is contraindicated in persons with mild to severe liver disease.
Side effects
The most common side effects are dizziness (11.5%) and constipation (10.9%). Other side effects include headache and nausea.
Drug interactions
Ranolazine is metabolized mainly by the CYP3A enzyme. It also inhibits another metabolizing enzyme, cytochrome CYP2D6. For this reason, the doses of ranolazine and drugs that interact with those enzymes need to be adjusted when they are used by the same patient.
Ranolazine should not be used with drugs such as ketoconazole, clarithromycin, and nelfinavir that strongly inhibit CYP3A, nor with drugs that activate CYP3A, such as rifampin and phenobarbital.For drugs that are moderate CYP3A inhibitors, such as diltiazem, verapamil, and erythromycin, the dose of ranolazine should be reduced.Drugs that are metabolized by CYP2D6, such as tricyclic antidepressants, may need to be given at reduced doses when administered with ranolazine.
Mechanism of action
Ranolazine inhibits persistent or late inward sodium current (INa) in heart muscle in a variety of voltage-gated sodium channels. Inhibiting that current leads to reductions in intracellular calcium levels. This in turn leads to reduced tension in the heart wall, leading to reduced oxygen requirements for the muscle. The QT prolongation effect of ranolazine on the surface electrocardiogram is the result of inhibition of IKr, which prolongs the ventricular action potential. Ranolazine also exhibits its effects on the delayed rectifier current (hERG/IKr potassium channels), it readily stimulates myogenesis, it reduces a pro-oxidant inflammation/oxidative condition, and activates the calcium signaling pathway.Ranolazine prolongs the action potential duration, with corresponding QT interval prolongation on electrocardiography, blocks the INa current, and prevents calcium overload caused by the hyperactive INa current, thus it stabilizes the membrane and reducing excitability.
History
Syntex Inc. originally began developing ranolazine in 1985 and 61 studies were completed from then until 1994. Afterwards, Phase 2 studies were done however it was found that the formulation did not result in adequate plasma concentrations of drug. It is due to this that the sustained-release (SR) formulation of ranolazine was created.Roche acquired Syntex in 1994 In 1996, CV Therapeutics licensed the North American and European rights to ranolazine from Syntex, a subsidiary of Roche, which had discovered the drug and had developed it through Phase II trials in angina. In 2006, CV Therapeutics acquired the remaining worldwide rights to ranolazine from Roche. In 2008 CV Therapeutics exclusively licensed rights for ranolazine in Europe and some other countries to Menarini.
In 2009, Gilead acquired CV Therapeutics. In 2013 Gilead expanded the partnership with Menarini to include additional countries, including those in Asia.
Society and culture
Legal status
Ranolazine was approved by the FDA in January 2006, for the treatment of patients with chronic angina as a second-line treatment in addition to other drugs. In 2007 the label was updated to make ranolazine a first-line treatment, alone or with other drugs. In April 2008 ranolazine was approved by the European EMEA for use in angina.
Commercial aspects
Ranolazine is manufactured and sold as Ranexa by Gilead. According to a Gilead annual income statement, combined sales for Ranexa and another Gilead product, AmBisom, were $621 million for the fourth quarter of 2016.
References
External links
"Ranolazine". Drug Information Portal. U.S. National Library of Medicine. |
Ivacaftor | Ivacaftor is a medication used to treat cystic fibrosis in people with certain mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene (primarily the G551D mutation), who account for 4–5% cases of cystic fibrosis. It is also included in combination medications, lumacaftor/ivacaftor, tezacaftor/ivacaftor, and elexacaftor/tezacaftor/ivacaftor which are used to treat people with cystic fibrosis.Ivacaftor was developed by Vertex Pharmaceuticals in conjunction with the Cystic Fibrosis Foundation and is the first medication that treats the underlying cause rather than the symptoms of the disease. It was approved by the U.S. Food and Drug Administration (FDA) in January 2012. It is one of the most expensive drugs, costing over US$300,000 per year, which has led to criticism of the high cost. The combination drug lumacaftor/ivacaftor was approved by the FDA in July 2015.Cystic fibrosis is caused by any one of several defects in the CFTR protein, which regulates fluid flow within cells and affects the components of sweat, digestive fluids, and mucus. One such defect is the G551D mutation, in which the amino acid glycine (G) in position 551 is replaced with aspartic acid (D). G551D is characterized by a dysfunctional CFTR protein on the cell surface. In the case of G551D, the protein is trafficked to the correct area, the epithelial cell surface, but once there the protein cannot transport chloride through the channel. Ivacaftor, a CFTR potentiator, improves the transport of chloride through the ion channel by binding to the channels directly to induce a non-conventional mode of gating which in turn increases the probability that the channel is open.
Medical uses
Ivacaftor is used for the treatment of cystic fibrosis in people having one of several specific mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein: E56K, G178R, S549R, K1060T, G1244E, P67L, E193K, G551D, A1067T, S1251N, R74W, L206W, G551S, G1069R, S1255P, D110E, R347H, D579G, R1070Q, D1270N, D110H, R352Q, S945L, R1070W, G1349D, R117C, A455E, S977F, F1074L, R117H, S549N, F1052V, D1152H.Ivacaftor is also included in a combination product, lumacaftor/ivacaftor, in a single pill, which is used to treat people with cystic fibrosis who have the F508del mutation in CFTR.Ivacaftor is also included in the combination product tezacaftor/ivacaftor with ivacaftor sold as Symdeko and as Symkevi.Symdeko is indicated to treat people aged six and older who have two copies of the F508del mutation in CFTR.Symkevi is indicated in a combination regimen with ivacaftor 150 mg tablets for the treatment of people with cystic fibrosis (CF) aged twelve years and older who are homozygous for the F508del mutation or who are heterozygous for the F508del mutation and have one of the following mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene: P67L, R117C, L206W, R352Q, A455E, D579G, 711+3A→G, S945L, S977F, R1070W, D1152H, 2789+5G→A, 3272 26A→G, and 3849+10kbC→T.Ivacaftor is available in a combination product with elexacaftor and tezacaftor called Trikafta for the treatment of people with cystic fibrosis who have the F508del mutation or other mutations.
Adverse effects
The most common adverse reactions experienced by patients who received ivacaftor in the pooled placebo-controlled Phase III studies were abdominal pain (15.6% versus 12.5% on placebo), diarrhoea (12.8% versus 9.6% on placebo), dizziness (9.2% versus 1.0% on placebo), rash (12.8% versus 6.7% on placebo), upper respiratory tract reactions (including upper respiratory tract infection, nasal congestion, pharyngeal erythema, oropharyngeal pain, rhinitis, sinus congestion, and nasopharyngitis) (63.3% versus 50.0% on placebo), headache (23.9% versus 16.3% on placebo) and bacteria in sputum (7.3% versus 3.8% on placebo). One patient in the ivacaftor group reported a serious adverse reaction: abdominal pain.
Pharmacology
Pharmacodynamics
Ivacaftor is a "potentiator" of CFTR, meaning it increases the probability that the defective channel will be open and allow chloride ions pass through the channel pore.
Pharmacokinetics
Distribution
Ivacaftor is approximately 99% bound to plasma proteins, primarily to alpha 1-acid glycoprotein and albumin. Ivacaftor does not bind to human red blood cells.
Biotransformation
Ivacaftor is extensively metabolised in humans. In vitro and in vivo data indicate that ivacaftor is primarily metabolised by CYP3A. M1 and M6 are the two major metabolites of ivacaftor in humans. M1 has approximately one-sixth the potency of ivacaftor and is considered pharmacologically active. M6 has less than one-fiftieth the potency of ivacaftor and is not considered pharmacologically active.
Elimination
Following oral administration, the majority of ivacaftor (87.8%) is eliminated in the faeces after metabolic conversion. The major metabolites M1 and M6 accounted for approximately 65% of total dose eliminated with 22% as M1 and 43% as M6. There was negligible urinary excretion of ivacaftor as unchanged parent. The apparent terminal half-life was approximately 12 hours following a single dose in the fed state. The apparent clearance (CL/F) of ivacaftor was similar for healthy subjects and patients with CF. The mean (±SD) of CL/F for the 150 mg dose was 17.3 (8.4) L/h in healthy subjects at steady state.
Society and culture
Legal status
The U.S. Food and Drug Administration (FDA) approved ivacaftor in January 2012, and soon afterwards so too did the European Medicines Agency (EMA) and Canada and across some European countries.Lumacaftor/ivacaftor was approved by the FDA in July 2015, under breakthrough therapy status and under a priority review.
Economics
The cost of ivacaftor is US$311,000 per year, roughly similar to the price of other medications for extremely rare diseases. In the first nine months of its second year on the market (2014), ivacaftor sales were $339M, representing 54% of Vertexs product sales revenue. During the same period, total drug development expenses were $458M, most of which was spent on cystic fibrosis-related research.An editorial in JAMA called the price of ivacaftor "exorbitant", citing the support by the Cystic Fibrosis Foundation in its development and the contribution made by fundamental scientific research performed by the National Institutes of Health and relied upon by Vertex in its cystic fibrosis drug discovery programs. The company responded in an email that "while publicly funded academic research provided important early understanding of the cause of cystic fibrosis, it took Vertex scientists 14 years of their own research, funded mostly by the company, before the drug won approval."The Cystic Fibrosis Foundation, a non-profit organization dedicated to improving healthcare for people with cystic fibrosis, provided $150 million of the funding for the development for ivacaftor in exchange for royalty rights in the event that the medication was successfully developed and commercialized. In 2014, the Foundation sold these royalty rights for $3.3 billion. The Foundation has stated that it intends to spend these funds in support of further research.Vertex said it would make the medication available free to patients in the United States with no insurance and a household income of under $150,000. In 2012, 24 US doctors and researchers involved in the development of the medication wrote to Vertex to protest the price of the medication, which had been set at about $300,000 per year. In the UK, the company provided the medication free for a limited time for certain patients, then left the hospitals to decide whether to continue to pay for it for those patients. UK agencies estimated the cost per quality adjusted life year (QALY) at between £335,000 and £1,274,000 —well above the National Institute for Health and Care Excellence thresholds.The medication was not covered under the Ontario Drug Benefit plan until June 2014, when the Government of Ontario and the manufacturer negotiated for what "Ontario Health Minister Deb Matthews had called a "fair price" for taxpayers". The negotiations took 16 months and it was estimated that around 20 Ontarians required the medication at the time.The province of Alberta began covering the medication in July 2014, and in September the province of Saskatchewan became the third province to include it in its provincial medication plan.Delay in agreement on a price for Vertex to charge national health plans led to patient group protests in Wales, England, and Australia.As of March 2016, the combination medication cost $259,000 a year in the United States.
Research
The clinical trials used in the regulatory approval of ivacaftor are described here.
G551D mutation
Of the approximately 70,000 cases of cystic fibrosis worldwide, 4% (~3,000) are due to a mutation called G551D. The safety and efficacy of ivacaftor for the treatment of cystic fibrosis in patients with this mutation was examined in two clinical trials.The first trial was performed in adults having baseline respiratory function (FEV1) between 32% and 98% of normal for persons of similar age, height, and weight. The baseline average was 64%. Improvement in FEV1 was rapid and sustained. At the end of 48 weeks, people treated with ivacaftor had on average an absolute increase in FEV1 of 10.4%, vs. a decline of 0.2% in the placebo group. Pulmonary exacerbations were reduced by about half in the ivacaftor group relative to the placebo group.In a second trial conducted in children age six to 11, the average improvement in FEV1 was an absolute increase of 12.5% in the ivacaftor group at 48 weeks, compared to a very slight decline in the placebo group.
Other mutations
A third clinical trial examined the efficacy of ivacaftor in people with cystic fibrosis due to G1244E, G1349D, G178R, G551S, S1251N, S1255P, S549N, or S549R mutations. This trial, which included 39 people of age greater than six years, used a crossover design. The people in the trial had FEV1 averaging 78% of normal at baseline. The people in the trial were randomized to receive either ivacaftor or placebo for eight weeks. This was followed by a four to eight week washout period, then each group received the opposite treatment from what it received in the first part of the trial. At week 8, the people on treatment with ivacaftor experienced an average absolute improvement in FEV1 of 13.8%, but there was a strong dependence of the efficacy on the exact mutation that a patient had. The detailed data for different mutation types is shown in the U.S package insert.
References
External links
"Ivacaftor". Drug Information Portal. U.S. National Library of Medicine.
"Ivacaftor mixture with lumacaftor". Drug Information Portal. U.S. National Library of Medicine.
"Ivacaftor regimen with Tezacaftor". Drug Information Portal. U.S. National Library of Medicine.
"Lumacaftor and Ivacaftor". MedlinePlus.
"Tezacaftor and Ivacaftor". MedlinePlus.
"Elexacaftor, Tezacaftor, and Ivacaftor". MedlinePlus. |
Fenfluramine | Fenfluramine, sold under the brand name Fintepla, is a serotonergic medication used for the treatment of seizures associated with Dravet syndrome and Lennox–Gastaut syndrome. It was formerly used as an appetite suppressant in the treatment of obesity, but was discontinued for this use due to cardiovascular toxicity before being repurposed for new indications. Fenfluramine was used for weight loss both alone under the brand name Pondimin and in combination with phentermine under the brand name Fen-Phen among others.Side effects of fenfluramine in people treated for seizures include decreased appetite, somnolence, sedation, lethargy, diarrhea, constipation, abnormal echocardiogram, fatigue, malaise, asthenia, ataxia, balance disorder, gait disturbance, increased blood pressure, drooling, excessive salivation, fever, upper respiratory tract infection, vomiting, appetite loss, weight loss, falls, and status epilepticus. Fenfluramine acts as a serotonin releasing agent, agonist of the serotonin 5-HT2 receptors, and σ1 receptor positive modulator. Its mechanism of action in the treatment of seizures is unknown, but may involve increased activation of certain serotonin receptors and the σ1 receptor.Fenfluramine was developed in the early 1960s and was first introduced for medical use as an appetite suppressant in France in 1963 followed by approval in the United States in 1973. In the 1990s, fenfluramine came to be associated with cardiovascular toxicity, and because of this, was withdrawn from the United States market in 1997. Subsequently, it was repurposed for the treatment of seizures and was reintroduced in the United States and the European Union in 2020. Fenfluramine is a schedule IV controlled substance in the United States.
Medical uses
Seizures
Fenfluramine is indicated for the treatment of seizures associated with Dravet syndrome and Lennox–Gastaut syndrome in people age two and older.Dravet syndrome is a life-threatening, rare and chronic form of epilepsy. It is often characterized by severe and unrelenting seizures despite medical treatment.
Obesity
Fenfluramine was formerly used as an appetite suppressant in the treatment of obesity, but was withdrawn for this use due to cardiovascular toxicity.
Adverse effects
The most common adverse reactions in people with seizures include decreased appetite; drowsiness, sedation and lethargy; diarrhea; constipation; abnormal echocardiogram; fatigue or lack of energy; ataxia (lack of coordination), balance disorder, gait disturbance (trouble with walking); increased blood pressure; drooling, salivary hypersecretion (saliva overproduction); pyrexia (fever); upper respiratory tract infection; vomiting; decreased weight; risk of falls; and status epilepticus.The U.S. Food and Drug Administration (FDA) fenfluramine labeling includes a boxed warning stating the drug is associated with valvular heart disease (VHD) and pulmonary arterial hypertension (PAH). Because of the risks of VHD and PAH, fenfluramine is available only through a restricted drug distribution program, under a risk evaluation and mitigation strategy (REMS). The fenfluramine REMS requires health care professionals who prescribe fenfluramine and pharmacies that dispense fenfluramine to be specially certified in the fenfluramine REMS and that patients be enrolled in the REMS. As part of the REMS requirements, prescribers and patients must adhere to the required cardiac monitoring with echocardiograms to receive fenfluramine.At higher therapeutic doses, headache, diarrhea, dizziness, dry mouth, erectile dysfunction, anxiety, insomnia, irritability, lethargy, and CNS stimulation have been reported with fenfluramine.There have been reports associating chronic fenfluramine treatment with emotional instability, cognitive deficits, depression, psychosis, exacerbation of pre-existing psychosis (schizophrenia), and sleep disturbances. It has been suggested that some of these effects may be mediated by serotonergic neurotoxicity/depletion of serotonin with chronic administration and/or activation of serotonin 5-HT2A receptors.
Heart valve disease
The distinctive valvular abnormality seen with fenfluramine is a thickening of the leaflet and chordae tendineae. One mechanism used to explain this phenomenon involves heart valve serotonin receptors, which are thought to help regulate growth. Since fenfluramine and its active metabolite norfenfluramine stimulate serotonin receptors, this may have led to the valvular abnormalities found in patients using fenfluramine. In particular norfenfluramine is a potent inhibitor of the re-uptake of 5-HT into nerve terminals. Fenfluramine and its active metabolite norfenfluramine affect the 5-HT2B receptors, which are plentiful in human cardiac valves. The suggested mechanism by which fenfluramine causes damage is through over or inappropriate stimulation of these receptors leading to inappropriate valve cell division. Supporting this idea is the fact that this valve abnormality has also occurred in patients using other drugs that act on 5-HT2B receptors.According to a study of 5,743 former users conducted by a plaintiffs expert cardiologist, damage to the heart valve continued long after stopping the medication. Of the users tested, 20% of women, and 12% of men were affected. For all ex-users, there was a 7-fold increase of chances of needing surgery for faulty heart valves caused by the drug.
Overdose
In overdose, fenfluramine can cause serotonin syndrome and rapidly result in death.
Pharmacology
Pharmacodynamics
Fenfluramine acts primarily as a serotonin releasing agent. It increases the level of serotonin, a neurotransmitter that regulates mood, appetite and other functions. Fenfluramine causes the release of serotonin by disrupting vesicular storage of the neurotransmitter, and reversing serotonin transporter function. The drug also acts as a norepinephrine releasing agent to a lesser extent, particularly via its active metabolite norfenfluramine. At high concentrations, norfenfluramine, though not fenfluramine, also acts as a dopamine releasing agent, and so fenfluramine may do this at very high doses as well. In addition to monoamine release, while fenfluramine binds only very weakly to the serotonin 5-HT2 receptors, norfenfluramine binds to and activates the serotonin 5-HT2B and 5-HT2C receptors with high affinity and the serotonin 5-HT2A receptor with moderate affinity. The result of the increased serotonergic and noradrenergic neurotransmission is a feeling of fullness and reduced appetite.
The combination of fenfluramine with phentermine, a norepinephrine–dopamine releasing agent acting primarily on norepinephrine, results in a well-balanced serotonin–norepinephrine releasing agent with weaker effects of dopamine release.
Fenfluramine was identified as a potent positive modulator of the σ1 receptor in 2020 and this action may be involved in its therapeutic benefits in the treatment of seizures.
Pharmacokinetics
The elimination half-life of fenfluramine has been reported as ranging from 13 to 30 hours. The mean elimination half-lives of its enantiomers have been found to be 19 hours for dexfenfluramine and 25 hours for levfenfluramine. Norfenfluramine, the major active metabolite of fenfluramine, has an elimination half-life that is about 1.5 to 2 times as long as that of fenfluramine, with mean values of 34 hours for dexnorfenfluramine and 50 hours for levnorfenfluramine.
Chemistry
Fenfluramine is a substituted amphetamine and is also known as 3-trifluoromethyl-N-ethylamphetamine. It is a racemic mixture of two enantiomers, dexfenfluramine and levofenfluramine. Some analogues of fenfluramine include norfenfluramine, benfluorex, flucetorex, and fludorex.
History
Fenfluramine was developed in the early 1960s and was introduced in France in 1963. Approximately 50 million Europeans were treated with fenfluramine for appetite suppression between 1963 and 1996. Fenfluramine was approved in the United States in 1973. The combination of fenfluramine and phentermine was proposed in 1984. Approximately 5 million people in the United States were given fenfluramine or dexfenfluramine with or without phentermine between 1996 and 1998.In the early 1990s, French researchers reported an association of fenfluramine with primary pulmonary hypertension and dyspnea in a small sample of patients. Fenfluramine was withdrawn from the U.S. market in 1997 after reports of heart valve disease and continued findings of pulmonary hypertension, including a condition known as cardiac fibrosis. It was subsequently withdrawn from other markets around the world. It was banned in India in 1998.Fenfluramine was an appetite suppressant which was used to treat obesity. It was used both on its own and, in combination with phentermine, as part of the anti-obesity medication Fen-Phen.In June 2020, fenfluramine was approved for medical use in the United States with an indication to treat Dravet syndrome.The effectiveness of fenfluramine for the treatment of seizures associated with Dravet syndrome was demonstrated in two clinical studies in 202 subjects between ages two and eighteen. The studies measured the change from baseline in the frequency of convulsive seizures. In both studies, subjects treated with fenfluramine had significantly greater reductions in the frequency of convulsive seizures during the trials than subjects who received placebo (inactive treatment). These reductions were seen within 3–4 weeks, and remained generally consistent over the 14- to 15-week treatment periods.The U.S. Food and Drug Administration (FDA) granted the application for fenfluramine priority review and orphan drug designations. The FDA granted approval of Fintepla to Zogenix, Inc.On 15 October 2020, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Fintepla, intended for the treatment of seizures associated with Dravet syndrome. Fenfluramine was approved for medical use in the European Union in December 2020.
Society and culture
Recreational use
Unlike various other amphetamine derivatives, fenfluramine is reported to be dysphoric, "unpleasantly lethargic", and non-addictive at therapeutic doses. However, it has been reported to be used recreationally at high doses ranging between 80 and 400 mg, which have been described as producing euphoria, amphetamine-like effects, sedation, and hallucinogenic effects, along with anxiety, nausea, diarrhea, and sometimes panic attacks, as well as depressive symptoms once the drug had worn off. At very high doses (e.g., 240 mg, or between 200 and 600 mg), fenfluramine induces a psychedelic state resembling that produced by lysergic acid diethylamide (LSD). Indirect (via induction of serotonin release) and/or direct activation of the 5-HT2A receptor would be expected to be responsible for the psychedelic effects of the drug at sufficient doses.
References
Further reading
Gustafsson BI, Tømmerås K, Nordrum I, Loennechen JP, Brunsvik A, Solligård E, Fossmark R, Bakke I, Syversen U, Waldum H (March 2005). "Long-term serotonin administration induces heart valve disease in rats". Circulation. 111 (12): 1517–22. doi:10.1161/01.CIR.0000159356.42064.48. PMID 15781732.
Welch, J. T.; Lim, D. S. (2007). "The Synthesis and Biological Activity of Pentafluorosulfanyl Analogs of Fluoxetine, Fenfluramine, and Norfenfluramine". Bioorganic & Medicinal Chemistry. 15 (21): 6659–6666. doi:10.1016/j.bmc.2007.08.012. PMID 17765553.
External links
"Fenfluramine". Drug Information Portal. U.S. National Library of Medicine.
"Fenfluramine hydrochloride". Drug Information Portal. U.S. National Library of Medicine.
Inchem.org - Fenfluramine hydrochloride |
Calcitonin | Calcitonin is a 32 amino acid peptide hormone secreted by parafollicular cells (also known as C cells) of the thyroid (or endostyle) in humans and other chordates. in the ultimopharyngeal body. It acts to reduce blood calcium (Ca2+), opposing the effects of parathyroid hormone (PTH).Its importance in humans has not been as well established as its importance in other animals, as its function is usually not significant in the regulation of normal calcium homeostasis. It belongs to the calcitonin-like protein family.
Historically calcitonin has also been called thyrocalcitonin.
Biosynthesis and regulation
Calcitonin is formed by the proteolytic cleavage of a larger prepropeptide, which is the product of the CALC1 gene (CALCA). It is functionally an antagonist with PTH and Vitamin D3. The CALC1 gene belongs to a superfamily of related protein hormone precursors including islet amyloid precursor protein, calcitonin gene-related peptide, and the precursor of adrenomedullin.
Secretion of calcitonin is stimulated by:
an increase in serum [Ca2+]
gastrin and pentagastrin.
Function
The hormone participates in calcium (Ca2+) metabolism. In many ways, calcitonin counteracts parathyroid hormone (PTH) and vitamin D.
More specifically, calcitonin lowers blood Ca2+ levels in two ways:
Major effect: Inhibits osteoclast activity in bones, which break down the bone
Minor effect: Inhibits renal tubular cell reabsorption of Ca2+ and phosphate, allowing them to be excreted in the urineHigh concentrations of calcitonin may be able to increase urinary excretion of calcium and phosphate via the renal tubules. leading to marked hypocalcemia. However, this is a minor effect with no physiological significance in humans. It is also a short-lived effect because the kidneys become resistant to calcitonin, as demonstrated by the kidneys unaffected excretion of calcium in patients with thyroid tumors that secrete excessive calcitonin.In its skeleton-preserving actions, calcitonin protects against calcium loss from the skeleton during periods of calcium mobilization, such as pregnancy and, especially, lactation. The protective mechanisms include the direct inhibition of bone resorption and the indirect effect through the inhibition of the release of prolactin from the pituitary gland. The reason provided is that prolactin induces the release of PTH related peptide which enhances bone resorption, but is still under investigation.Other effects are in preventing postprandial hypercalcemia resulting from absorption of Ca2+. Also, calcitonin inhibits food intake in rats and monkeys, and may have CNS action involving the regulation of feeding and appetite.
Calcitonin lowers blood calcium and phosphorus mainly through its inhibition of osteoclasts. Osteoblasts do not have calcitonin receptors and are therefore not directly affected by calcitonin levels. However, since bone resorption and bone formation are coupled processes, eventually calcitonins inhibition of osteoclastic activity leads to increased osteoblastic activity (as an indirect effect).
Receptor
The calcitonin receptor is a G protein-coupled receptor localized to osteoclasts as well kidney and brain cells. It is coupled to a Gsα subunit, thus stimulating cAMP production by adenylate cyclase in target cells. It may also affect the ovaries in women and the testes in men.
Discovery
Calcitonin was first purified in 1962 by Douglas Harold Copp and B. Cheney at the University of British Columbia, Canada. It was initially thought to be secreted by the parathyroid gland but was shown by Iain Macintyre and his team at the Royal Postgraduate Medical School, London, to be secreted by parafollicular cells of the thyroid gland. Dr. Copp named the discovered hormone calcitonin because of its role in maintaining normal calcium tone.
Medical significance
Calcitonin assay is used in identifying patients with nodular thyroid diseases. It is helpful in making an early diagnosis of medullary carcinoma of thyroid. A malignancy of the parafollicular cells, i.e. Medullary thyroid cancer, typically produces an elevated serum calcitonin level. Prognosis of MTC depends on early detection and treatment.
Calcitonin also has significantly impacted molecular biology, as the gene encoding calcitonin was the first gene discovered in mammalian cells to be alternatively spliced, now known to be a ubiquitous mechanism in eukaryotes.
Pharmacology
Calcitonin has clinically been used for metabolic bone disorders for more than 50 years. Salmon calcitonin is used for the treatment of:
Postmenopausal osteoporosis
Hypercalcaemia
Bone metastases
Pagets disease
Phantom limb painIt has been investigated as a possible non-operative treatment for spinal stenosis.The following information is from the UK Electronic Medicines Compendium
General characteristics of the active substance
Salmon calcitonin is rapidly absorbed and eliminated. Peak plasma concentrations are attained within the first hour of administration.
Animal studies have shown that calcitonin is primarily metabolised via proteolysis in the kidney following parenteral administration. The metabolites lack the specific biological activity of calcitonin. Bioavailability following subcutaneous and intramuscular injection in humans is high and similar for the two routes of administration (71% and 66%, respectively).
Calcitonin has short absorption and elimination half-lives of 10–15 minutes and 50–80 minutes, respectively. Salmon calcitonin is primarily and almost exclusively degraded in the kidneys, forming pharmacologically inactive fragments of the molecule. Therefore, the metabolic clearance is much lower in patients with end-stage kidney failure than in healthy subjects. However, the clinical relevance of this finding is not known. Plasma protein binding is 30% to 40%.
Characteristics in patients
There is a relationship between the subcutaneous dose of calcitonin and peak plasma concentrations. Following parenteral administration of 100 IU calcitonin, peak plasma concentration lies between about 200 and 400 pg/ml. Higher blood levels may be associated with increased incidence of nausea, vomiting, and secretory diarrhea.
Preclinical safety data
Conventional long-term toxicity, reproduction, mutagenicity, and carcinogenicity studies have been performed in laboratory animals. Salmon calcitonin is devoid of embryotoxic, teratogenic, and mutagenic potential.
An increased incidence of pituitary adenomas has been reported in rats given synthetic salmon calcitonin for 1 year. This is considered a species-specific effect and of no clinical relevance. Salmon calcitonin does not cross the placental barrier.
In lactating animals given calcitonin, suppression of milk production has been observed. Calcitonin is secreted into the milk.
Pharmaceutical manufacture
Calcitonin was extracted from the ultimobranchial glands (thyroid-like glands) of fish, particularly salmon. Salmon calcitonin resembles human calcitonin, but is more active. At present, it is produced either by recombinant DNA technology or by chemical peptide synthesis. The pharmacological properties of the synthetic and recombinant peptides have been demonstrated to be qualitatively and quantitatively equivalent.
Uses of calcitonin
Treatments
Calcitonin can be used therapeutically for the treatment of hypercalcemia or osteoporosis.
In a recent clinical study, subcutaneous injections of calcitonin have reduced the incidence of fractures and reduced the decrease in bone mass in women with type 2 diabetes complicated with osteoporosis.Subcutaneous injections of calcitonin in patients with mania resulted in significant decreases in irritability, euphoria and hyperactivity and hence calcitonin holds promise for treating bipolar disorder. However no further work on this potential application of calcitonin has been reported.
Diagnostics
It may be used diagnostically as a tumor marker for medullary thyroid cancer, in which high calcitonin levels may be present and elevated levels after surgery may indicate recurrence. It may even be used on biopsy samples from suspicious lesions (e.g., lymph nodes that are swollen) to establish whether they are metastases of the original cancer.
Cutoffs for calcitonin to distinguish cases with medullary thyroid cancer have been suggested to be as follows, with a higher value increasing the suspicion of medullary thyroid cancer:
females: 5 ng/L or pg/mL
males: 12 ng/L or pg/mL
children under 6 months of age: 40 ng/L or pg/mL
children between 6 months and 3 years of age: 15 ng/L or pg/mLWhen over 3 years of age, adult cutoffs may be used
Increased levels of calcitonin have also been reported for various other conditions. They include: C-cell hyperplasia, nonthyroidal oat cell carcinoma, nonthyroidal carcinoma and other nonthyroidal malignancies, acute kidney injury and chronic kidney failure, hypercalcemia, hypergastrinemia, and other gastrointestinal disorders, and pulmonary disease.
Structure
Calcitonin is a polypeptide hormone of 32 amino acids, with a molecular weight of 3454.93 daltons. Its structure comprises a single alpha helix. Alternative splicing of the gene coding for calcitonin produces a distantly related peptide of 37 amino acids, called calcitonin gene-related peptide (CGRP), beta type.The following are the amino acid sequences of salmon and human calcitonin:
salmon:Cys-Ser-Asn-Leu-Ser-Thr-Cys-Val-Leu-Gly-Lys-Leu-Ser-Gln-Glu-Leu-His-Lys-Leu-Gln-Thr-Tyr-Pro-Arg-Thr-Asn-Thr-Gly-Ser-Gly-Thr-Pro
human:Cys-Gly-Asn-Leu-Ser-Thr-Cys-Met-Leu-Gly-Thr-Tyr-Thr-Gln-Asp-Phe-Asn-Lys-Phe-His-Thr-Phe-Pro-Gln-Thr-Ala-Ile-Gly-Val-Gly-Ala-Pro
Compared to salmon calcitonin, human calcitonin differs at 16 residues.
Research
In addition to the injectable and nasal spray dosage forms of the salmon calcitonin, noninvasive oral formulations of the peptide are currently under clinical development. The short-half-life of this peptide in serum triggered several attempts to enhance plasma concentrations. The peptide is complexed with a macromolecule that acts as an absorption enhancer through the transcellular pathway and, additionally, protects the peptide from the harsh pH and enzymatic conditions of the GI tract. This complexation is weak, noncovalent and reversible and the drug remains chemically unmodified. After passage through the intestine, the delivery agent dissociates from the peptide. One of the extensively studied oral formulations is the disodium salts of 5-CNAC oral calcitonin. This novel oral platform in a number of clinical trials at different phases has demonstrated promising enhanced pharmacokinetic profile, high bioavailability, well-established safety and comparable efficacy to that of nasal calcitonin especially for treatment of postmenopausal bone loss.
See also
Procalcitonin
References
Further reading
External links
The Calcitonin Protein
Calcitonin at the US National Library of Medicine Medical Subject Headings (MeSH) |
Lisocabtagene maraleucel | Lisocabtagene maraleucel, sold under the brand name Breyanzi, is a cell-based gene therapy used to treat large B-cell lymphoma.Side effects include hypersensitivity reactions, serious infections, low blood cell counts, and a weakened immune system. The most common side effects include decreases in neutrophils (a type of white blood cell that fights infections), in red blood cells or in blood platelets (components that help the blood to clot), as well as cytokine release syndrome (a potentially life-threatening condition that can cause fever, vomiting, shortness of breath, pain and low blood pressure) and tiredness.Lisocabtagene maraleucel, a chimeric antigen receptor (CAR) T cell (CAR-T) therapy, is the third gene therapy approved by the U.S. Food and Drug Administration (FDA) for certain types of non-Hodgkin lymphoma, including diffuse large B-cell lymphoma (DLBCL). Lisocabtagene maraleucel was approved for medical use in the United States in February 2021.
Medical uses
Lisocabtagene maraleucel is indicated for the treatment of adults with relapsed or refractory large B-cell lymphoma (DLBCL) after two or more lines of systemic therapy, including diffuse large B-cell lymphoma (DLBCL) not otherwise specified (including DLBCL arising from indolent lymphoma), high-grade B-cell lymphoma, primary mediastinal large B-cell lymphoma (PMBCL), and follicular lymphoma grade 3B (FL3B).Lisocabtagene maraleucel is indicated for the treatment of adults with large B-cell lymphoma (LBCL) who have refractory disease to first-line chemoimmunotherapy or relapse within twelve months of first-line chemoimmunotherapy; or refractory disease to first-line chemoimmunotherapy or relapse after first-line chemoimmunotherapy and are not eligible for hematopoietic stem cell transplantation (HSCT) due to comorbidities or age.Lisocabtagene maraleucel is not indicated for the treatment of people with primary central nervous system lymphoma.
Adverse effects
The labeling carries a boxed warning for cytokine release syndrome (CRS), which is a systemic response to the activation and proliferation of CAR-T cells, causing high fever and flu-like symptoms and neurologic toxicities.
History
Lisocabtagene maraleucels safety and efficacy were established in a multicenter clinical trial of more than 250 adults with refractory or relapsed large B-cell lymphoma. The complete remission rate after treatment was 54%.The U.S. Food and Drug Administration (FDA) granted lisocabtagene maraleucel priority review, orphan drug, regenerative medicine advanced therapy (RMAT), and breakthrough therapy designations. Lisocabtagene maraleucel is the first regenerative medicine therapy with RMAT designation to be licensed by the FDA. The FDA granted approval of Breyanzi to Juno Therapeutics Inc., a Bristol-Myers Squibb Company.Efficacy was evaluated in TRANSFORM (NCT03575351), a randomized, open-label, multicenter trial in adults with primary refractory LBCL or relapse within twelve months of achieving complete response (CR) to first-line therapy. Participants had not yet received treatment for relapsed or refractory lymphoma and were potential candidates for autologous HSCT. A total of 184 participants were randomized 1:1 to receive a single infusion of lisocabtagene maraleucel following fludarabine and cyclophosphamide lymphodepleting chemotherapy or to receive second-line standard therapy, consisting of three cycles of chemoimmunotherapy followed by high-dose therapy and autologous HSCT in participants who attained CR or partial response (PR).Efficacy was also evaluated in PILOT (NCT03483103), a single-arm, open-label, multicenter trial in transplant-ineligible patients with relapsed or refractory LBCL after one line of chemoimmunotherapy. The study enrolled participants who were ineligible for high-dose therapy and HSCT due to organ function or age, but who had adequate organ function for CAR-T cell therapy. Efficacy was based on CR rate and duration of response (DOR) as determined by an IRC. Of 74 participants who underwent leukapheresis (median age, 73 years), 61 (82%) received lisocabtagene maraleucel of whom 54% (95% CI: 41, 67) achieved CR. The median DOR was not reached (95% CI: 11.2 months, not reached) in participants who achieved CR and 2.1 months (95% CI: 1.4, 2.3) in participants with a best response of PR. Among all leukapheresed participants, the CR rate was 46% (95% CI: 34, 58).
Society and culture
Legal status
On 27 January 2022, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Breyanzi, intended for the treatment of adults with relapsed or refractory diffuse large B cell lymphoma (DLBCL), primary mediastinal large B-cell lymphoma (PMBCL) and follicular lymphoma grade 3B (FL3B), after at least two previous lines of treatments. The applicant for this medicinal product is Bristol-Myers Squibb Pharma EEIG. Lisocabtagene maraleucel was approved for medical use in the European Union in April 2022.
Names
Lisocabtagene maraleucel is the international nonproprietary name (INN).
References
External links
"Lisocabtagene maraleucel". NCI Drug Dictionary. National Cancer Institute.
Clinical trial number NCT02631044 for "Study Evaluating the Safety and Pharmacokinetics of JCAR017 in B-cell Non-Hodgkin Lymphoma (TRANSCEND-NHL-001)" at ClinicalTrials.gov
Manali Kamdar, MD, MBBS, an Associate Professor at the University of Colorado Denver gives a video interview entitled Lisocabtagene Maraleucel FDA Approved For Large B-cell Lymphoma - https://oncologytube.com/video/41258 |
Ampicillin | Ampicillin is an antibiotic used to prevent and treat a number of bacterial infections, such as respiratory tract infections, urinary tract infections, meningitis, salmonellosis, and endocarditis. It may also be used to prevent group B streptococcal infection in newborns. It is used by mouth, by injection into a muscle, or intravenously.
Common side effects include rash, nausea, and diarrhea. It should not be used in people who are allergic to penicillin. Serious side effects may include Clostridium difficile colitis or anaphylaxis. While usable in those with kidney problems, the dose may need to be decreased. Its use during pregnancy and breastfeeding appears to be generally safe.Ampicillin was discovered in 1958 and came into commercial use in 1961. It is on the World Health Organizations List of Essential Medicines. The World Health Organization classifies ampicillin as critically important for human medicine. It is available as a generic medication.
Medical uses
Diseases
Bacterial meningitis; an aminoglycoside can be added to increase efficacy against gram-negative meningitis bacteria
Endocarditis by enterococcal strains (off-label use); often given with an aminoglycoside
Gastrointestinal infections caused by contaminated water or food (for example, by Salmonella)
Genito-urinary tract infections
Healthcare-associated infections that are related to infections from using urinary catheters and that are unresponsive to other medications
Otitis media (middle ear infection)
Prophylaxis (i.e. to prevent infection) in those who previously had rheumatic heart disease or are undergoing dental procedures, vaginal hysterectomies, or C-sections. It is also used in pregnant woman who are carriers of group B streptococci to prevent early-onset neonatal infections.
Respiratory infections, including bronchitis, pharyngitis
Sinusitis
Sepsis
Whooping cough, to prevent and treat secondary infectionsAmpicillin used to also be used to treat gonorrhea, but there are now too many strains resistant to penicillins.
Bacteria
Ampicillin is used to treat infections by many gram-positive and gram-negative bacteria. It was the first "broad spectrum" penicillin with activity against gram-positive bacteria, including Streptococcus pneumoniae, Streptococcus pyogenes, some isolates of Staphylococcus aureus (but not penicillin-resistant or methicillin-resistant strains), Trueperella, and some Enterococcus. It is one of the few antibiotics that works against multidrug resistant Enterococcus faecalis and E. faecium. Activity against gram-negative bacteria includes Neisseria meningitidis, some Haemophilus influenzae, and some of the Enterobacteriaceae (though most Enterobacteriaceae and Pseudomonas are resistant). Its spectrum of activity is enhanced by co-administration of sulbactam, a drug that inhibits beta lactamase, an enzyme produced by bacteria to inactivate ampicillin and related antibiotics. It is sometimes used in combination with other antibiotics that have different mechanisms of action, like vancomycin, linezolid, daptomycin, and tigecycline.
Available forms
Ampicillin can be administered by mouth, an intramuscular injection (shot) or by intravenous infusion. The oral form, available as capsules or oral suspensions, is not given as an initial treatment for severe infections, but rather as a follow-up to an IM or IV injection. For IV and IM injections, ampicillin is kept as a powder that must be reconstituted.IV injections must be given slowly, as rapid IV injections can lead to convulsive seizures.
Specific populations
Ampicillin is one of the most used drugs in pregnancy, and has been found to be generally harmless both by the Food and Drug Administration in the U.S. (which classified it as category B) and the Therapeutic Goods Administration in Australia (which classified it as category A). It is the drug of choice for treating Listeria monocytogenes in pregnant women, either alone or combined with an aminoglycoside. Pregnancy increases the clearance of ampicillin by up to 50%, and a higher dose is thus needed to reach therapeutic levels.Ampicillin crosses the placenta and remains in the amniotic fluid at 50–100% of the concentration in maternal plasma; this can lead to high concentrations of ampicillin in the newborn.While lactating mothers secrete some ampicillin into their breast milk, the amount is minimal.In newborns, ampicillin has a longer half-life and lower plasma protein binding. The clearance by the kidneys is lower, as kidney function has not fully developed.
Contraindications
Ampicillin is contraindicated in those with a hypersensitivity to penicillins, as they can cause fatal anaphylactic reactions. Hypersensitivity reactions can include frequent skin rashes and hives, exfoliative dermatitis, erythema multiforme, and a temporary decrease in both red and white blood cells.Ampicillin is not recommended in people with concurrent mononucleosis, as over 40% of patients develop a skin rash.
Side effects
Ampicillin is comparatively less toxic than other antibiotics, and side effects are more likely in those who are sensitive to penicillins and those with a history of asthma or allergies. In very rare cases, it causes severe side effects such as angioedema, anaphylaxis, and C. difficile infection (that can range from mild diarrhea to serious pseudomembranous colitis). Some develop black "furry" tongue. Serious adverse effects also include seizures and serum sickness. The most common side effects, experienced by about 10% of users are diarrhea and rash. Less common side effects can be nausea, vomiting, itching, and blood dyscrasias. The gastrointestinal effects, such as hairy tongue, nausea, vomiting, diarrhea, and colitis, are more common with the oral form of penicillin. Other conditions may develop up several weeks after treatment.
Overdose
Ampicillin overdose can cause behavioral changes, confusion, blackouts, and convulsions, as well as neuromuscular hypersensitivity, electrolyte imbalance, and kidney failure.
Interactions
Ampicillin reacts with probenecid and methotrexate to decrease renal excretion. Large doses of ampicillin can increase the risk of bleeding with concurrent use of warfarin and other oral anticoagulants, possibly by inhibiting platelet aggregation. Ampicillin has been said to make oral contraceptives less effective, but this has been disputed. It can be made less effective by other antibiotic, such as chloramphenicol, erythromycin, cephalosporins, and tetracyclines. For example, tetracyclines inhibit protein synthesis in bacteria, reducing the target against which ampicillin acts. If given at the same time as aminoglycosides, it can bind to it and inactivate it. When administered separately, aminoglycosides and ampicillin can potentiate each other instead.Ampicillin causes skin rashes more often when given with allopurinol.Both the live cholera vaccine and live typhoid vaccine can be made ineffective if given with ampicillin. Ampicillin is normally used to treat cholera and typhoid fever, lowering the immunological response that the body has to mount.
Pharmacology
Mechanism of action
Ampicillin is in the penicillin group of beta-lactam antibiotics and is part of the aminopenicillin family. It is roughly equivalent to amoxicillin in terms of activity. Ampicillin is able to penetrate gram-positive and some gram-negative bacteria. It differs from penicillin G, or benzylpenicillin, only by the presence of an amino group. This amino group, present on both ampicillin and amoxicillin, helps these antibiotics pass through the pores of the outer membrane of gram-negative bacteria, such as E. coli, Proteus mirabilis, Salmonella enterica, and Shigella.Ampicillin acts as an irreversible inhibitor of the enzyme transpeptidase, which is needed by bacteria to make the cell wall. It inhibits the third and final stage of bacterial cell wall synthesis in binary fission, which ultimately leads to cell lysis; therefore, ampicillin is usually bacteriolytic.
Pharmacokinetics
Ampicillin is well-absorbed from the GI tract (though food reduces its absorption), and reaches peak concentrations in one to two hours. The bioavailability is around 62% for parenteral routes. Unlike other penicillins, which usually bind 60–90% to plasma proteins, ampicillin binds to only 15–20%.Ampicillin is distributed through most tissues, though it is concentrated in the liver and kidneys. It can also be found in the cerebrospinal fluid when the meninges become inflamed (such as, for example, meningitis). Some ampicillin is metabolized by hydrolyzing the beta-lactam ring to penicilloic acid, though most of it is excreted unchanged. In the kidneys, it is filtered out mostly by tubular secretion; some also undergoes glomerular filtration, and the rest is excreted in the feces and bile.
Hetacillin and pivampicillin are ampicillin esters that have been developed to increase bioavailability.
History
Ampicillin has been used extensively to treat bacterial infections since 1961. Until the introduction of ampicillin by the British company Beecham, penicillin therapies had only been effective against gram-positive organisms such as staphylococci and streptococci. Ampicillin (originally branded as "Penbritin") also demonstrated activity against gram-negative organisms such as H. influenzae, coliforms, and Proteus spp.
Cost
Ampicillin is relatively inexpensive. In the United States, it is available as a generic medication.
Veterinary use
In veterinary medicine, ampicillin is used in cats, dogs, and farm animals to treat:
Anal gland infections
Cutaneous infections, such as abscesses, cellulitis, and pustular dermatitis
E. coli and Salmonella infections in cattle, sheep, and goats (oral form). Ampicillin use for this purpose had declined as bacterial resistance has increased.
Mastitis in sows
Mixed aerobic–anaerobic infections, such as from cat bites
Multidrug-resistant Enterococcus faecalis and E. faecium
Prophylactic use in poultry against Salmonella and sepsis from E. coli or Staphylococcus aureus
Respiratory tract infections, including tonsilitis, bovine respiratory disease, shipping fever, bronchopneumonia, and calf and bovine pneumonia
Urinary tract infections in dogsHorses are generally not treated with ampicillin, as they have low bioavailability of beta-lactams.The half-life in animals is around that same of that in humans (just over an hour). Oral absorption is less than 50% in cats and dogs, and less than 4% in horses.
See also
Amoxycillin (p-hydroxy metabolite of ampicillin)
Pivampicillin (special pro-drug of ampicillin)
Azlocillin and pirbenicillin (urea and amide made from ampicillin)
References
External links
"Ampicillin". Drug Information Portal. U.S. National Library of Medicine.
GB patent 902703, Frank Peter Doyle, John Herbert Charles Nayler, Harry Smith, "Penicillins", published 1962-08-09, assigned to Beecham Research Laboratories Ltd
US patent 2985648, Frank Peter Doyle, John Herbert Charles Nayler, Harry Smith, "Alpha-aminobenzylpenicillins", published 1961-05-23, issued 1961-05-23
US patent 3157640, David A Johnson & Glenn A Hardcastle Jr, "D-(-)-alpha-aminobenzylpenicillin trihydrate", published 1964-11-17, issued 1964-11-17, assigned to Bristol Myers Co |
Midodrine | Midodrine is a vasopressor/antihypotensive agent (it raises the blood pressure). Midodrine was approved in the United States by the Food and Drug Administration (FDA) in 1996 for the treatment of dysautonomia and orthostatic hypotension. In August 2010, the FDA proposed withdrawing this approval because the manufacturer, Shire plc, failed to complete required studies after the medicine reached the market. In September 2010, the FDA reversed its decision to remove midodrine from the market and allowed it to remain available to patients while Shire plc collected further data regarding the efficacy and safety of the drug. Shire announced on September 22, 2011, that it was withdrawing completely from supplying midodrine and leaving it to several generics to supply the drug.
Medical uses
Midodrine is indicated for the treatment of symptomatic orthostatic hypotension. It can reduce dizziness and faints by about a third, but can be limited by troublesome goose bumps, skin itch, gastrointestinal discomfort, chills, elevated blood pressure while lying down, and urinary retention. A meta-analysis of clinical trials of midodrine or droxidopa in patients with low blood pressure when standing found that midodrine increased standing blood pressure more than droxidopa but that midodrine but not droxidopa increased the risk of high blood pressure when lying down. Small studies have also shown that midodrine can be used to prevent excessive drops in blood pressure in people requiring dialysis.Midodrine has been used in the complications of cirrhosis. It is also used with octreotide for hepatorenal syndrome; the proposed mechanism is constriction of splanchnic vessels and dilation of renal vasculature. Studies have not been sufficiently well conducted to show a clear place for midodrine.
Contraindications
Midodrine is contraindicated in patients with severe organic heart disease, acute kidney disease, urinary retention, pheochromocytoma or thyrotoxicosis. Midodrine should not be used in patients with persistent and excessive supine hypertension.
Side effects
Headache, feeling of pressure/fullness in the head, vasodilation/flushing face, scalp tingling, confusion/thinking abnormality, dry mouth, nervousness/anxiety and rash.
Pharmacology
Mechanism of action
Midodrine is a prodrug which forms an active metabolite, desglymidodrine, which is an α1-receptor agonist and exerts its actions via activation of the alpha-adrenergic receptors of the arteriolar and venous vasculature, producing an increase in vascular tone and elevation of blood pressure. Desglymidodrine does not stimulate cardiac beta-adrenergic receptors. Desglymidodrine diffuses poorly across the blood–brain barrier, and is therefore not associated with effects on the central nervous system.
Pharmacokinetics
After oral administration, midodrine is rapidly absorbed. The plasma levels of the prodrug peak after about half an hour, and decline with a half-life of approximately 25 minutes, while the metabolite reaches peak blood concentrations about 1 to 2 hours after a dose of midodrine and has a half-life of about 3 to 4 hours. The absolute bioavailability of midodrine (measured as desglymidodrine) is 93%.
Chemistry
Midodrine is an odorless, white, crystalline powder, soluble in water and sparingly soluble in methanol.
Stereochemistry
Midodrine contains a stereocenter and consists of two enantiomers, making it a racemate; i.e., a 1:1 mixture of (R)- and (S)-forms:
Synthesis
Acylation of 1,4-dimethoxybenzene with chloroacetyl chloride gives the chloroketone 2. The halogen is then converted to the amine 3 by any set of standard schemes, and the ketone reduced to an alcohol with borohydride (4). Acylation of the amino group in this last intermediate with chloroacetyl chloride affords the amide 5. The halogen is then displaced with azide and the resulting product 6 reduced catalytically to the glycinamide, midodrine (7).
References
External links
Media related to Midodrine at Wikimedia Commons
"Midodrine". Drug Information Portal. U.S. National Library of Medicine. |
Triethylenetetramine | Triethylenetetramine (TETA and trien), also known as trientine (INN) when used medically, is an organic compound with the formula [CH2NHCH2CH2NH2]2. The pure freebase is a colorless oily liquid, but, like many amines, older samples assume a yellowish color due to impurities resulting from air-oxidation. It is soluble in polar solvents. The branched isomer tris(2-aminoethyl)amine and piperazine derivatives may also be present in commercial samples of TETA.
The hydrochloride salts are used medically as a treatment for copper toxicity.
Uses
The reactivity and uses of TETA are similar to those for the related polyamines ethylenediamine and diethylenetriamine. It is primarily used as a crosslinker ("hardener") in epoxy curing.
Medical uses
The hydrochloride salt of TETA, referred to as trientine hydrochloride, is a chelating agent that is used to bind and remove copper in the body to treat Wilsons disease, particularly in those who are intolerant to penicillamine. Some recommend trientine as first-line treatment, but experience with penicillamine is more extensive.Trientine hydrochloride (brand name Syprine) was approved for medical use in the United States in November 1985.Trientine tetrahydrochloride (brand name Cuprior) was approved for medical use in the European Union in September 2017. It is indicated for the treatment of Wilsons disease in adults, adolescents and children five years of age or older who are intolerant to D-penicillamine therapy.Trientine dihydrochloride (brand name Cufence) was approved for medical use in the European Union in July 2019. It is indicated for the treatment of Wilsons disease in adults, adolescents and children five years of age or older who are intolerant to D-penicillamine therapy.The most common side effects include nausea, especially when starting treatment, skin rash, duodenitis (inflammation of the duodenum, the part of the gut leading out of the stomach), and severe colitis (inflammation in the large bowel causing pain and diarrhea).
Society and culture
Controversies
In the United States, Valeant Pharmaceuticals International raised the price of its Syprine brand of TETA from $625 to $21,267 for 100 pills over five years. The New York Times said that this "egregious" price increase caused public outrage. Teva Pharmaceuticals developed a generic, which patients and doctors expected to be cheaper, but when it was introduced in February 2018, Tevas price was $18,375 for 100 pills. Aaron Kesselheim, who studies drug pricing at Harvard Medical School, said that drug companies price the product at what they think the market will bear.
Production
TETA is prepared by heating ethylenediamine or ethanolamine/ammonia mixtures over an oxide catalyst. This process gives a variety of amines, especially ethylene amines which are separated by distillation and sublimation.
Coordination chemistry
TETA is a tetradentate ligand in coordination chemistry, where it is referred to as trien. Octahedral complexes of the type M(trien)L2 can adopt several diastereomeric structures.
References
External links
"Triethylenetetramine". Drug Information Portal. U.S. National Library of Medicine.
"Trientine hydrochloride". Drug Information Portal. U.S. National Library of Medicine.
"Trientine tetrahydrochloride". Drug Information Portal. U.S. National Library of Medicine. |
Belzutifan | Belzutifan, sold under the brand name Welireg, is a medication used for the treatment of von Hippel–Lindau disease-associated renal cell carcinoma. It is taken by mouth.The most common side effects include decreased hemoglobin, anemia, fatigue, increased creatinine, headache, dizziness, increased glucose, and nausea.Belzutifan is an hypoxia-inducible factor-2 alpha (HIF-2α) inhibitor.Belzutifan is the first drug to be awarded an "innovation passport" from the UK Medicines and Healthcare products Regulatory Agency (MHRA). Belzutifan was approved for medical use in the United States in August 2021. Belzutifan is the first hypoxia-inducible factor-2 alpha inhibitor therapy approved in the U.S.
Medical uses
Belzutifan is indicated for treatment of adults with von Hippel-Lindau (VHL) disease who require therapy for associated renal cell carcinoma (RCC), central nervous system (CNS) hemangioblastomas, or pancreatic neuroendocrine tumors (pNET), not requiring immediate surgery. Belzutifan was also found to be efficacious in an adolescent who had Pacak–Zhuang syndrome with polycythemia and paragangliomas.
References
External links
"Belzutifan". Drug Information Portal. U.S. National Library of Medicine.
Clinical trial number NCT04195750 for "A Study of Belzutifan (MK-6482) Versus Everolimus in Participants With Advanced Renal Cell Carcinoma (MK-6482-005)" at ClinicalTrials.gov
Clinical trial number NCT03401788 for "A Phase 2 Study of Belzutifan (PT2977, MK-6482) for the Treatment of Von Hippel Lindau (VHL) Disease-Associated Renal Cell Carcinoma (RCC) (MK-6482-004)" at ClinicalTrials.gov |
Potassium phosphate | Potassium phosphate is a generic term for the salts of potassium and phosphate ions including:
Monopotassium phosphate (KH2PO4) (Molar mass approx: 136 g/mol)
Dipotassium phosphate (K2HPO4) (Molar mass approx: 174 g/mol)
Tripotassium phosphate (K3PO4) (Molar mass approx: 212.27 g/mol)As food additives, potassium phosphates have the E number E340.
== References == |
Ecallantide | Ecallantide (trade name Kalbitor) is a drug used for the treatment of hereditary angioedema (HAE) and in the prevention of blood loss in cardiothoracic surgery. It is an inhibitor of the protein kallikrein and a 60-amino acid polypeptide which was developed from a Kunitz domain through phage display to mimic antibodies inhibiting kallikrein.
Medical uses
Angioedema
On November 27, 2009, ecallantide was approved by the FDA for the treatment of acute attacks of hereditary angioedema for persons over 16 years of age. A single dose requires three separate injections, which are given under the skin.Ecallantide does not appear to be efficacious for the treatment of angioedema due to ACE inhibitors.
Adverse effects
The most common adverse effects are headache, nausea, fatigue and diarrhea. Less common, but observed in more than 5% of patients in clinical trials, are respiratory tract infections, fever, vomiting, itching and upper abdominal pain. Up to 4% of patients showed anaphylaxis, which led to a black box warning in the US.
Interactions
As of 2011, no interaction studies have been conducted.
Mechanism of action
HAE is caused by a mutation of the C1-inhibitor gene. Defective or missing C1-inhibitor permits activation of kallikrein, a protease that is responsible for liberating bradykinin from its precursor kininogen. An excess of bradykinin leads to fluid leakage from blood vessels, causing swelling of tissues typical of HAE.
Ecallantide suppresses this pathogenetic mechanism by selectively and reversibly inhibiting the activity of plasma kallikrein. Ecallantides inhibitory constant (Ki) for kallikrein is 25 picoMolar, indicating high affinity.
See also
Icatibant, another drug for the treatment of HAE
== References == |
Oxymetazoline | Oxymetazoline, sold under the brand name Afrin among others, is a topical decongestant and vasoconstrictor medication. It is available over-the-counter as a nasal spray to treat nasal congestion and nosebleeds, as eyedrops to treat eye redness due to minor irritation, and (in the United States) as a prescription topical cream to treat persistent facial redness due to rosacea in adults. Its effects begin within minutes and last for up to 6 hours. Intranasal use for longer than three days may cause congestion to recur or worsen, resulting in physical dependence.
Oxymetazoline is a derivative of imidazole. It was developed from xylometazoline at E. Merck Darmstadt by Wolfgang Fruhstorfer and Helmut Müller-Calgan in 1961. A direct sympathomimetic, oxymetazoline binds to and activates α1 adrenergic receptors and α2 adrenergic receptors, most notably. One study classified it in the following order: α(2A) > α(1A) ≥ α(2B) > α(1D) ≥ α(2C) >> α(1B), but this is not universally agreed upon. There is little consistency across the (relatively large) number of in-vitro studies with respect to binding affinity/selectivity.
Medical uses
Oxymetazoline is available over-the-counter as a topical decongestant in the form of oxymetazoline hydrochloride in nasal sprays such as Otrivin, Afrin, Operil, Dristan, Dimetapp, Oxyspray, Facimin, Nasivin, Nostrilla, Utabon, Sudafed OM, Vicks Sinex, Zicam, SinuFrin, Drixoral
and Mucinex Full Force.In the United States, oxymetazoline 1% cream is approved by the Food and Drug Administration for topical treatment of persistent facial erythema (redness) associated with rosacea in adults.Due to its vasoconstricting properties, oxymetazoline is also used to treat nose bleeds and eye redness due to minor irritation (marketed as Visine L.R. in the form of eye drops). In July 2020, oxymetazoline received approval by the FDA for the treatment of acquired drooping eyelid.
Side effects
Rebound congestion
Rebound congestion, or rhinitis medicamentosa, may occur. A 2006 review of the pathology of rhinitis medicamentosa concluded that use of oxymetazoline for more than three days may result in rhinitis medicamentosa and recommended limiting use to three days.
Australian regulatory submission
In a submission to the Therapeutic Goods Administration, a Novartis representative concluded, "The justification was not based on evidence." Citing an existing extensive body of evidence and noting a range of recommended periods from five to ten days, Novartis recommended the established five day period for its use for self-medication without medical consultation as it coincides with the typical duration of the common cold.
Use in pregnancy
The Food and Drug Administration places oxymetazoline in category C, indicating risk to the fetus cannot be ruled out. While it has been shown that a single dose does not significantly alter either maternal or fetal circulation, this subject has not been studied extensively enough to draw reliable conclusions.
Overdose
If accidentally ingested, standard methods to remove unabsorbed drugs should be considered. There is no specific antidote for oxymetazoline, although its pharmacological effects may be reversed by an adrenergic antagonists such as phentolamine. In the event of a possibly life-threatening overdose (such as a hypertensive crisis), benzodiazepines should be considered to decrease the likelihood of seizures and convulsions, as well as reduce anxiety and to lower blood pressure. In children, oxymetazoline may produce profound central nervous system depression due to stimulation of central α2 receptors and imidazoline receptors, much like clonidine.
Pharmacology
Pharmacodynamics
Oxymetazoline is a sympathomimetic that selectively agonizes α1 and, partially, α2 adrenergic receptors. Since vascular beds widely express α1 receptors, the action of oxymetazoline results in vasoconstriction. In addition, the local application of the drug also results in vasoconstriction due to its action on endothelial postsynaptic α2 receptors; systemic application of α2 agonists, in contrast, causes vasodilation because of centrally-mediated inhibition of sympathetic tone via presynaptic α2 receptors. Vasoconstriction of vessels results in relief of nasal congestion in two ways: first, it increases the diameter of the airway lumen; second, it reduces fluid exudation from postcapillary venules. It can reduce nasal airway resistance (NAR) up to 35.7% and reduce nasal mucosal blood flow up to 50%.
Pharmacokinetics
Since imidazolines are sympathomimetic agents, their primary effects appear on α adrenergic receptors, with little if any effect on β adrenergic receptors. Like other imidazolines, Oxymetazoline is readily absorbed orally. Effects on α receptors from systemically absorbed oxymetazoline hydrochloride may persist for up to 7 hours after a single dose. The elimination half-life in humans is 5–8 hours. It is excreted unchanged both by the kidneys (30%) and in feces (10%).
History
The oxymetazoline brand Afrin was first sold as a prescription medication in 1966. After finding substantial early success as a prescription medication, it became available as an over-the-counter drug in 1975. Schering-Plough did not engage in heavy advertising until 1986.From the mid-1980s to mid-1990s, the brand Sinex was featured in many television advertisements. Some of these commercials showed men, women, and children using other brands of nasal sprays, and then standing upside down on a sidewalk, or against a wall, etc. or hanging upside down from various playground equipment to prevent their nasal spray from dripping out. This was juxtaposed with Sinex users not having to hang upside side down or stand on their heads as it didnt drip out.
Brand names
Brand names include Afrin, Drixine, Dristan, Nasivin, Nasivion, Nezeril, Nostrilla, Logicin, Vicks Sinex, Visine L.R., Sudafed OM, Zicam, Otrivin Oxy, SinuFrin, Upneeq, and Mucinex Sinus-Max.
== References == |
Cetirizine | Cetirizine, sold under the brand name Zyrtec among others, is a second-generation antihistamine used to treat allergic rhinitis (hay fever), dermatitis, and urticaria (hives). It is taken by mouth. Effects generally begin within thirty minutes and last for about a day. The degree of benefit is similar to other antihistamines such as diphenhydramine.Common side effects include sleepiness, dry mouth, headache, and abdominal pain. The degree of sleepiness that occurs is generally less than with first generation antihistamines. Use in pregnancy appears safe, but use during breastfeeding is not recommended. The medication works by blocking histamine H1 receptors, mostly outside the brain.It was patented in 1981 and came into medical use in 1987. It is on the World Health Organizations List of Essential Medicines. It is available as a generic medication. In 2020, it was the 52nd most commonly prescribed medication in the United States, with more than 13 million prescriptions.
Medical uses
Allergies
Cetirizines primary indication is for hay fever and other allergies. Because the symptoms of itching and redness in these conditions are caused by histamine acting on the H1 receptor, blocking those receptors temporarily relieves those symptoms.Cetirizine is also commonly prescribed to treat acute and (in particular cases) chronic urticaria, more efficiently than any other second-generation antihistamine.
Available forms
Cetirizine is available over-the-counter in the US in the form of 5 and 10 mg tablets. A 20 mg strength is available by prescription only. It is also available as a 1 mg/mL syrup for oral administration by prescription.
In the UK, up to 30 tablets of 10 mg are on the general sales list (of pharmaceuticals) and can be purchased without a prescription and without pharmacist supervision. The drug can be in the form of tablets, capsules or a syrup.
Adverse effects
Commonly reported side effects of cetirizine include headache, dry mouth, drowsiness, and fatigue, while more serious but rare adverse effects reported include tachycardia and edema.Discontinuing cetirizine after prolonged use (typically, use beyond six months) may result in generalized itching.
Pharmacology
Pharmacodynamics
Cetirizine acts as a highly selective antagonist of the histamine H1 receptor. The Ki values for the H1 receptor are approximately 6 nM for cetirizine, 3 nM for levocetirizine, and 100 nM for dextrocetirizine, indicating that the levorotatory enantiomer is the main active form. Cetirizine has 600-fold or greater selectivity for the H1 receptor over a wide variety of other sites, including muscarinic acetylcholine, serotonin, dopamine, and α-adrenergic receptors, among many others. The drug shows 20,000-fold or greater selectivity for the H1 receptor over the five muscarinic acetylcholine receptors, and hence does not exhibit anticholinergic effects. It shows negligible inhibition of the hERG channel (IC50 > 30 μM) and no cardiotoxicity has been observed with cetirizine at doses of up to 60 mg/day, six times the normal recommended dose and the highest dose of cetirizine that has been studied in healthy subjects.Cetirizine crosses the blood-brain barrier only slightly, and for this reason, produces minimal sedation compared to many other antihistamines. A positron emission tomography (PET) study found that brain occupancy of the H1 receptor was 12.6% for 10 mg cetirizine, 25.2% for 20 mg cetirizine, and 67.6% for 30 mg hydroxyzine. (A 10 mg dose of cetirizine equals about a 30 mg dose of hydroxyzine in terms of peripheral antihistamine effect.) PET studies with antihistamines have found that brain H1 receptor occupancy of more than 50% is associated with a high prevalence of somnolence and cognitive decline, whereas brain H1 receptor occupancy of less than 20% is considered to be non-sedative. In accordance, H1 receptor occupancy correlated well with subjective sleepiness for 30 mg hydroxyzine but there was no correlation for 10 or 20 mg cetirizine. As such, brain penetration and brain H1 receptor occupancy by cetirizine are dose-dependent, and in accordance, while cetirizine at doses of 5 to 10 mg have been reported to be non-sedating or mildly sedating, a higher dose of 20 mg has been found to induce significant drowsiness in other studies.Cetirizine also shows anti-inflammatory properties independent of H1 receptors. The effect is exhibited through suppression of the NF-κB pathway, and by regulating the release of cytokines and chemokines, thereby regulating the recruitment of inflammatory cells. It has been shown to inhibit eosinophil chemotaxis and LTB4 release. At a dosage of 20 mg, Boone et al. found that it inhibited the expression of VCAM-1 in patients with atopic dermatitis.
Pharmacokinetics
Absorption
Cetirizine is rapidly and extensively absorbed upon oral administration in tablet or syrup form. The oral bioavailability of cetirizine is at least 70% and of levocetirizine is at least 85%. The Tmax of cetirizine is approximately 1.0 hour regardless of formulation. The pharmacokinetics of cetirizine have been found to increase linearly with dose across a range of 5 to 60 mg. Its Cmax following a single dose has been found to be 257 ng/mL for 10 mg and 580 ng/mL for 20 mg. Food has no effect on the bioavailability of cetirizine but has been found to delay the Tmax by 1.7 hours (i.e., to approximately 2.7 hours) and to decrease the Cmax by 23%. Similar findings were reported for levocetirizine, which had its Tmax delayed by 1.25 hours and its Cmax decreased by about 36% when administered with a high-fat meal. Steady-state levels of cetirizine occur within 3 days and there is no accumulation of the drug with chronic administration. Following once-daily administration of 10 mg cetirizine for ten days, the mean Cmax was 311 ng/mL.
Distribution
The mean plasma protein binding of cetirizine has been found to be 93 to 96% across a range of 25 to 1,000 ng/mL independent of concentration. Plasma protein binding of 88 to 96% has also been reported across multiple studies. The drug is bound to albumin with high affinity, while α1-acid glycoprotein and lipoproteins contribute much less to total plasma protein binding. The unbound or free fraction of levocetirizine has been reported to be 8%. The true volume of distribution of cetirizine is unknown but is estimated to be 0.3 to 0.45 L/kg. Cetirizine poorly and slowly crosses the blood-brain barrier, which is thought to be due to its chemical properties and its activity as a P-glycoprotein substrate.
Metabolism
Cetirizine does not undergo extensive metabolism. It is notably not metabolized by the cytochrome P450 system. Because of this, it does not interact significantly with drugs that inhibit or induce cytochrome P450 enzymes such as theophylline, erythromycin, clarithromycin, cimetidine, or alcohol. While cetirizine does not undergo extensive metabolism or metabolism by the cytochrome P450 enzyme, it does undergo some metabolism by other means, the metabolic pathways of which include oxidation and conjugation. Plasma radioactivity attributed to unchanged cetirizine is more than 90% at 2 hours, 80% at 10 hours, and 70% at 24 hours, indicating limited and slow metabolism. The enzymes responsible for transformation of cetirizine have not been identified.
Elimination
Cetirizine is eliminated approximately 70 to 85% in the urine and 10 to 13% in the feces. About 50 or 60% of cetirizine eliminated in the urine is unchanged. It is eliminated in the urine via an active transport mechanism. The elimination half-life of cetirizine ranges from 6.5 to 10 hours in healthy adults, with a mean across studies of approximately 8.3 hours. Its duration of action is at least 24 hours. The elimination half-life of cetirizine is increased in the elderly (to 12 hours), in hepatic impairment (to 14 hours), and in renal impairment (to 20 hours).
Chemistry
Cetirizine contains L- and D-stereoisomers. Chemically, levocetirizine is the active L-enantiomer of cetirizine. The drug is a member of the diphenylmethylpiperazine group of antihistamines. Analogues include cyclizine and hydroxyzine.
Synthesis
The 1-(4-chlorophenylmethyl)-piperazine is alkylated with methyl (2-chloroethoxy)-acetate in the presence of sodium carbonate and xylene solvent to produce the Sn2 substitution product in 28% yield. Saponification of the acetate ester is done by refluxing with potassium hydroxide in absolute ethanol to afford a 56% yield of the potassium salt intermediate. This is then hydrolyzed with aqueous HCl and extracted to give an 81% yield of the carboxylic acid product.
Availability
Formerly prescription-only in many countries, cetirizine is now available without prescription in most countries. In some countries it is available over-the-counter only in packages containing seven or ten 10 mg doses.Like many other antihistamine medications, cetirizine is commonly prescribed in combination with pseudoephedrine, a decongestant. These combinations are often marketed using the same brand name as the cetirizine with a "-D" suffix (Zyrtec-D, Virlix-D, etc.)Cetirizine is marketed under the brand names Alatrol, Alerid, Alzene, Cerchio, Cetirin, Cetriz, Cetzine, Cezin, Cetgel, Cirrus, Histec, Histazine, Humex, Letizen, Okacet (Cipla), Piriteze, Reactine, Razene, Rigix, Sensahist (Oethmann, South Africa), Triz, Zetop, Zirtec, Zirtek, Zodac, Zyllergy, Zynor, Zyrlek, and Zyrtec (Johnson & Johnson), among others.
References
External links
"Cetirizine". Drug Information Portal. U.S. National Library of Medicine.
Cetirizine Tablet Uses In Hindi |
Methamphetamine | Methamphetamine (contracted from N-methylamphetamine) is a potent central nervous system (CNS) stimulant that is mainly used as a recreational drug and less commonly as a second-line treatment for attention deficit hyperactivity disorder and obesity. Methamphetamine was discovered in 1893 and exists as two enantiomers: levo-methamphetamine and dextro-methamphetamine. Methamphetamine properly refers to a specific chemical substance, the racemic free base, which is an equal mixture of levomethamphetamine and dextromethamphetamine in their pure amine forms. It is rarely prescribed over concerns involving human neurotoxicity and potential for recreational use as an aphrodisiac and euphoriant, among other concerns, as well as the availability of safer substitute drugs with comparable treatment efficacy such as Adderall and Vyvanse. Dextromethamphetamine is a stronger CNS stimulant than levomethamphetamine.
Both racemic methamphetamine and dextromethamphetamine are illicitly trafficked and sold owing to their potential for recreational use. The highest prevalence of illegal methamphetamine use occurs in parts of Asia and Oceania, and in the United States, where racemic methamphetamine and dextromethamphetamine are classified as schedule II controlled substances. Levomethamphetamine is available as an over-the-counter (OTC) drug for use as an inhaled nasal decongestant in the United States. Internationally, the production, distribution, sale, and possession of methamphetamine is restricted or banned in many countries, due to its placement in schedule II of the United Nations Convention on Psychotropic Substances treaty. While dextromethamphetamine is a more potent drug, racemic methamphetamine is illicitly produced more often due to the relative ease of synthesis and regulatory limits of chemical precursor availability.
In low to moderate doses, methamphetamine can elevate mood, increase alertness, concentration and energy in fatigued individuals, reduce appetite, and promote weight loss. At very high doses, it can induce psychosis, breakdown of skeletal muscle, seizures and bleeding in the brain. Chronic high-dose use can precipitate unpredictable and rapid mood swings, stimulant psychosis (e.g., paranoia, hallucinations, delirium, and delusions) and violent behavior. Recreationally, methamphetamines ability to increase energy has been reported to lift mood and increase sexual desire to such an extent that users are able to engage in sexual activity continuously for several days while binging the drug. Methamphetamine is known to possess a high addiction liability (i.e., a high likelihood that long-term or high dose use will lead to compulsive drug use) and high dependence liability (i.e. a high likelihood that withdrawal symptoms will occur when methamphetamine use ceases). Withdrawal from methamphetamine after heavy use may lead to a post-acute-withdrawal syndrome, which can persist for months beyond the typical withdrawal period. Methamphetamine is neurotoxic to human midbrain dopaminergic neurons at high doses. Methamphetamine has been shown to have a higher affinity and, as a result, higher toxicity toward serotonergic neurons than amphetamine. Methamphetamine neurotoxicity causes adverse changes in brain structure and function, such as reductions in grey matter volume in several brain regions, as well as adverse changes in markers of metabolic integrity.
Methamphetamine belongs to the substituted phenethylamine and substituted amphetamine chemical classes. It is related to the other dimethylphenethylamines as a positional isomer of these compounds, which share the common chemical formula C10H15N.
Uses
Medical
In the United States, methamphetamine hydrochloride, under the trade name Desoxyn, has been approved by the FDA for treating ADHD and obesity in both adults and children; however, the FDA also indicates that the limited therapeutic usefulness of methamphetamine should be weighed against the inherent risks associated with its use. Methamphetamine is sometimes prescribed off label for narcolepsy and idiopathic hypersomnia. In the United States, methamphetamines levorotary form is available in some over-the-counter (OTC) nasal decongestant products.As methamphetamine is associated with a high potential for misuse, the drug is regulated under the Controlled Substances Act and is listed under Schedule II in the United States. Methamphetamine hydrochloride dispensed in the United States is required to include a boxed warning regarding its potential for recreational misuse and addiction liability.Desoxyn and Desoxyn Gradumet are both pharmaceutical forms of the drug. The latter is no longer produced and is a gradual-release form of the drug, flattening the curve of the effect of the drug while extending it.
Recreational
Methamphetamine is often used recreationally for its effects as a potent euphoriant and stimulant as well as aphrodisiac qualities.According to a National Geographic TV documentary on methamphetamine, an entire subculture known as party and play is based around sexual activity and methamphetamine use. Participants in this subculture, which consists almost entirely of homosexual male methamphetamine users, will typically meet up through internet dating sites and have sex. Due to its strong stimulant and aphrodisiac effects and inhibitory effect on ejaculation, with repeated use, these sexual encounters will sometimes occur continuously for several days on end. The crash following the use of methamphetamine in this manner is very often severe, with marked hypersomnia (excessive daytime sleepiness). The party and play subculture is prevalent in major US cities such as San Francisco and New York City.
Contraindications
Methamphetamine is contraindicated in individuals with a history of substance use disorder, heart disease, or severe agitation or anxiety, or in individuals currently experiencing arteriosclerosis, glaucoma, hyperthyroidism, or severe hypertension. The FDA states that individuals who have experienced hypersensitivity reactions to other stimulants in the past or are currently taking monoamine oxidase inhibitors should not take methamphetamine. The FDA also advises individuals with bipolar disorder, depression, elevated blood pressure, liver or kidney problems, mania, psychosis, Raynauds phenomenon, seizures, thyroid problems, tics, or Tourette syndrome to monitor their symptoms while taking methamphetamine. Due to the potential for stunted growth, the FDA advises monitoring the height and weight of growing children and adolescents during treatment.
Adverse effects
Physical
The physical effects of methamphetamine can include loss of appetite, hyperactivity, dilated pupils, flushed skin, excessive sweating, increased movement, dry mouth and teeth grinding (leading to "meth mouth"), headache, irregular heartbeat (usually as accelerated heartbeat or slowed heartbeat), rapid breathing, high blood pressure, low blood pressure, high body temperature, diarrhea, constipation, blurred vision, dizziness, twitching, numbness, tremors, dry skin, acne, and pale appearance. Long-term meth users may have sores on their skin; these may be caused by scratching due to itchiness or the belief that insects are crawling under their skin, and the damage is compounded by poor diet and hygiene. Numerous deaths related to methamphetamine overdoses have been reported.
Meth mouth
Methamphetamine users and addicts may lose their teeth abnormally quickly, regardless of the route of administration, from a condition informally known as meth mouth. The condition is generally most severe in users who inject the drug, rather than swallow, smoke, or inhale it. According to the American Dental Association, meth mouth "is probably caused by a combination of drug-induced psychological and physiological changes resulting in xerostomia (dry mouth), extended periods of poor oral hygiene, frequent consumption of high-calorie, carbonated beverages and bruxism (teeth grinding and clenching)". As dry mouth is also a common side effect of other stimulants, which are not known to contribute severe tooth decay, many researchers suggest that methamphetamine-associated tooth decay is more due to users other choices. They suggest the side effect has been exaggerated and stylized to create a stereotype of current users as a deterrence for new ones.
Sexually transmitted infection
Methamphetamine use was found to be related to higher frequencies of unprotected sexual intercourse in both HIV-positive and unknown casual partners, an association more pronounced in HIV-positive participants. These findings suggest that methamphetamine use and engagement in unprotected anal intercourse are co-occurring risk behaviors, behaviors that potentially heighten the risk of HIV transmission among gay and bisexual men. Methamphetamine use allows users of both sexes to engage in prolonged sexual activity, which may cause genital sores and abrasions as well as priapism in men. Methamphetamine may also cause sores and abrasions in the mouth via bruxism, increasing the risk of sexually transmitted infection.Besides the sexual transmission of HIV, it may also be transmitted between users who share a common needle. The level of needle sharing among methamphetamine users is similar to that among other drug injection users.
Fatal
Doses of 200 mg or more of methamphetamine are considered fatal.
Psychological
The psychological effects of methamphetamine can include euphoria, dysphoria, changes in libido, alertness, apprehension and concentration, decreased sense of fatigue, insomnia or wakefulness, self-confidence, sociability, irritability, restlessness, grandiosity and repetitive and obsessive behaviors. Peculiar to methamphetamine and related stimulants is "punding", persistent non-goal-directed repetitive activity. Methamphetamine use also has a high association with anxiety, depression, amphetamine psychosis, suicide, and violent behaviors.
Neurotoxic and neuroimmunological
Methamphetamine is directly neurotoxic to dopaminergic neurons in both lab animals and humans. Excitotoxicity, oxidative stress, metabolic compromise, UPS dysfunction, protein nitration, endoplasmic reticulum stress, p53 expression and other processes contributed to this neurotoxicity. In line with its dopaminergic neurotoxicity, methamphetamine use is associated with a higher risk of Parkinsons disease. In addition to its dopaminergic neurotoxicity, a review of evidence in humans indicated that high-dose methamphetamine use can also be neurotoxic to serotonergic neurons. It has been demonstrated that a high core temperature is correlated with an increase in the neurotoxic effects of methamphetamine. Withdrawal of methamphetamine in dependent persons may lead to post-acute withdrawal which persists months beyond the typical withdrawal period.Magnetic resonance imaging studies on human methamphetamine users have also found evidence of neurodegeneration, or adverse neuroplastic changes in brain structure and function. In particular, methamphetamine appears to cause hyperintensity and hypertrophy of white matter, marked shrinkage of hippocampi, and reduced gray matter in the cingulate cortex, limbic cortex, and paralimbic cortex in recreational methamphetamine users. Moreover, evidence suggests that adverse changes in the level of biomarkers of metabolic integrity and synthesis occur in recreational users, such as a reduction in N-acetylaspartate and creatine levels and elevated levels of choline and myoinositol.Methamphetamine has been shown to activate TAAR1 in human astrocytes and generate cAMP as a result. Activation of astrocyte-localized TAAR1 appears to function as a mechanism by which methamphetamine attenuates membrane-bound EAAT2 (SLC1A2) levels and function in these cells.Methamphetamine binds to and activates both sigma receptor subtypes, σ1 and σ2, with micromolar affinity. Sigma receptor activation may promote methamphetamine-induced neurotoxicity by facilitating hyperthermia, increasing dopamine synthesis and release, influencing microglial activation, and modulating apoptotic signaling cascades and the formation of reactive oxygen species.
Addictive
Current models of addiction from chronic drug use involve alterations in gene expression in certain parts of the brain, particularly the nucleus accumbens. The most important transcription factors that produce these alterations are ΔFosB, cAMP response element binding protein (CREB), and nuclear factor kappa B (NFκB). ΔFosB plays a crucial role in the development of drug addictions, since its overexpression in D1-type medium spiny neurons in the nucleus accumbens is necessary and sufficient for most of the behavioral and neural adaptations that arise from addiction. Once ΔFosB is sufficiently overexpressed, it induces an addictive state that becomes increasingly more severe with further increases in ΔFosB expression. It has been implicated in addictions to alcohol, cannabinoids, cocaine, methylphenidate, nicotine, opioids, phencyclidine, propofol, and substituted amphetamines, among others.ΔJunD, a transcription factor, and G9a, a histone methyltransferase enzyme, both directly oppose the induction of ΔFosB in the nucleus accumbens (i.e., they oppose increases in its expression). Sufficiently overexpressing ΔJunD in the nucleus accumbens with viral vectors can completely block many of the neural and behavioral alterations seen in chronic drug use (i.e., the alterations mediated by ΔFosB). ΔFosB also plays an important role in regulating behavioral responses to natural rewards, such as palatable food, sex, and exercise. Since both natural rewards and addictive drugs induce expression of ΔFosB (i.e., they cause the brain to produce more of it), chronic acquisition of these rewards can result in a similar pathological state of addiction. ΔFosB is the most significant factor involved in both amphetamine addiction and amphetamine-induced sex addictions, which are compulsive sexual behaviors that result from excessive sexual activity and amphetamine use. These sex addictions (i.e., drug-induced compulsive sexual behaviors) are associated with a dopamine dysregulation syndrome which occurs in some patients taking dopaminergic drugs, such as amphetamine or methamphetamine.
Epigenetic factors
Methamphetamine addiction is persistent for many individuals, with 61% of individuals treated for addiction relapsing within one year. About half of those with methamphetamine addiction continue with use over a ten-year period, while the other half reduce use starting at about one to four years after initial use.The frequent persistence of addiction suggests that long-lasting changes in gene expression may occur in particular regions of the brain, and may contribute importantly to the addiction phenotype. Recently a crucial role has been found for epigenetic mechanisms in driving lasting changes in gene expression in the brain.A review in 2015 summarized a number of studies involving chronic methamphetamine use in rodents. Epigenetic alterations were observed in the brain reward pathways, including areas like ventral tegmental area, nucleus accumbens, and dorsal striatum, the hippocampus, and the prefrontal cortex. Chronic methamphetamine use caused gene-specific histone acetylations, deacetylations and methylations. Gene-specific DNA methylations in particular regions of the brain were also observed. The various epigenetic alterations caused downregulations or upregulations of specific genes important in addiction. For instance, chronic methamphetamine use caused methylation of the lysine in position 4 of histone 3 located at the promoters of the c-fos and the C-C chemokine receptor 2 (ccr2) genes, activating those genes in the nucleus accumbens (NAc). c-fos is well known to be important in addiction. The ccr2 gene is also important in addiction, since mutational inactivation of this gene impairs addiction.In methamphetamine addicted rats, epigenetic regulation through reduced acetylation of histones, in brain striatal neurons, caused reduced transcription of glutamate receptors. Glutamate receptors play an important role in regulating the reinforcing effects of misused illicit drugs.Administration of methamphetamine to rodents causes DNA damage in their brain, particularly in the nucleus accumbens region. During repair of such DNA damages, persistent chromatin alterations may occur such as in the methylation of DNA or the acetylation or methylation of histones at the sites of repair. These alterations can be epigenetic scars in the chromatin that contribute to the persistent epigenetic changes found in methamphetamine addiction.
Treatment and management
A 2018 systematic review and network meta-analysis of 50 trials involving 12 different psychosocial interventions for amphetamine, methamphetamine, or cocaine addiction found that combination therapy with both contingency management and community reinforcement approach had the highest efficacy (i.e., abstinence rate) and acceptability (i.e., lowest dropout rate). Other treatment modalities examined in the analysis included monotherapy with contingency management or community reinforcement approach, cognitive behavioral therapy, 12-step programs, non-contingent reward-based therapies, psychodynamic therapy, and other combination therapies involving these.As of December 2019, there is no effective pharmacotherapy for methamphetamine addiction. A systematic review and meta-analysis from 2019 assessed the efficacy of 17 different pharmacotherapies used in RCTs for amphetamine and methamphetamine addiction; it found only low-strength evidence that methylphenidate might reduce amphetamine or methamphetamine self-administration. There was low- to moderate-strength evidence of no benefit for most of the other medications used in RCTs, which included antidepressants (bupropion, mirtazapine, sertraline), antipsychotics (aripiprazole), anticonvulsants (topiramate, baclofen, gabapentin), naltrexone, varenicline, citicoline, ondansetron, prometa, riluzole, atomoxetine, dextroamphetamine, and modafinil.
Dependence and withdrawal
Tolerance is expected to develop with regular methamphetamine use and, when used recreationally, this tolerance develops rapidly. In dependent users, withdrawal symptoms are positively correlated with the level of drug tolerance. Depression from methamphetamine withdrawal lasts longer and is more severe than that of cocaine withdrawal.According to the current Cochrane review on drug dependence and withdrawal in recreational users of methamphetamine, "when chronic heavy users abruptly discontinue [methamphetamine] use, many report a time-limited withdrawal syndrome that occurs within 24 hours of their last dose". Withdrawal symptoms in chronic, high-dose users are frequent, occurring in up to 87.6% of cases, and persist for three to four weeks with a marked "crash" phase occurring during the first week. Methamphetamine withdrawal symptoms can include anxiety, drug craving, dysphoric mood, fatigue, increased appetite, increased movement or decreased movement, lack of motivation, sleeplessness or sleepiness, and vivid or lucid dreams.Methamphetamine that is present in a mothers bloodstream can pass through the placenta to a fetus and be secreted into breast milk. Infants born to methamphetamine-abusing mothers may experience a neonatal withdrawal syndrome, with symptoms involving of abnormal sleep patterns, poor feeding, tremors, and hypertonia. This withdrawal syndrome is relatively mild and only requires medical intervention in approximately 4% of cases.
Neonatal
Unlike other drugs, babies with prenatal exposure to methamphetamines dont show immediate signs of withdrawal. Instead, cognitive and behavioral problems start emerging when the children reach school age.A prospective cohort study of 330 children showed that at the age of 3, children with methamphetamine exposure showed increased emotional reactivity, as well as more signs of anxiety and depression; and at the age of 5, children showed higher rates of externalizing and attention deficit/hyperactivity disorders.
Overdose
A methamphetamine overdose may result in a wide range of symptoms. A moderate overdose of methamphetamine may induce symptoms such as: abnormal heart rhythm, confusion, difficult and/or painful urination, high or low blood pressure, high body temperature, over-active and/or over-responsive reflexes, muscle aches, severe agitation, rapid breathing, tremor, urinary hesitancy, and an inability to pass urine. An extremely large overdose may produce symptoms such as adrenergic storm, methamphetamine psychosis, substantially reduced or no urine output, cardiogenic shock, bleeding in the brain, circulatory collapse, hyperpyrexia (i.e., dangerously high body temperature), pulmonary hypertension, kidney failure, rapid muscle breakdown, serotonin syndrome, and a form of stereotypy ("tweaking"). A methamphetamine overdose will likely also result in mild brain damage due to dopaminergic and serotonergic neurotoxicity. Death from methamphetamine poisoning is typically preceded by convulsions and coma.
Psychosis
Use of methamphetamine can result in a stimulant psychosis which may present with a variety of symptoms (e.g., paranoia, hallucinations, delirium, and delusions). A Cochrane Collaboration review on treatment for amphetamine, dextroamphetamine, and methamphetamine use-induced psychosis states that about 5–15% of users fail to recover completely. The same review asserts that, based upon at least one trial, antipsychotic medications effectively resolve the symptoms of acute amphetamine psychosis. Amphetamine psychosis may also develop occasionally as a treatment-emergent side effect.
Emergency treatment
Acute methamphetamine intoxication is largely managed by treating the symptoms and treatments may initially include administration of activated charcoal and sedation. There is not enough evidence on hemodialysis or peritoneal dialysis in cases of methamphetamine intoxication to determine their usefulness. Forced acid diuresis (e.g., with vitamin C) will increase methamphetamine excretion but is not recommended as it may increase the risk of aggravating acidosis, or cause seizures or rhabdomyolysis. Hypertension presents a risk for intracranial hemorrhage (i.e., bleeding in the brain) and, if severe, is typically treated with intravenous phentolamine or nitroprusside. Blood pressure often drops gradually following sufficient sedation with a benzodiazepine and providing a calming environment.Antipsychotics such as haloperidol are useful in treating agitation and psychosis from methamphetamine overdose. Beta blockers with lipophilic properties and CNS penetration such as metoprolol and labetalol may be useful for treating CNS and cardiovascular toxicity. The mixed alpha- and beta-blocker labetalol is especially useful for treatment of concomitant tachycardia and hypertension induced by methamphetamine. The phenomenon of "unopposed alpha stimulation" has not been reported with the use of beta-blockers for treatment of methamphetamine toxicity.
Interactions
Methamphetamine is metabolized by the liver enzyme CYP2D6, so CYP2D6 inhibitors will prolong the elimination half-life of methamphetamine. Methamphetamine also interacts with monoamine oxidase inhibitors (MAOIs), since both MAOIs and methamphetamine increase plasma catecholamines; therefore, concurrent use of both is dangerous. Methamphetamine may decrease the effects of sedatives and depressants and increase the effects of antidepressants and other stimulants as well. Methamphetamine may counteract the effects of antihypertensives and antipsychotics due to its effects on the cardiovascular system and cognition respectively. The pH of gastrointestinal content and urine affects the absorption and excretion of methamphetamine. Specifically, acidic substances will reduce the absorption of methamphetamine and increase urinary excretion, while alkaline substances do the opposite. Due to the effect pH has on absorption, proton pump inhibitors, which reduce gastric acid, are known to interact with methamphetamine.
Pharmacology
Pharmacodynamics
Methamphetamine has been identified as a potent full agonist of trace amine-associated receptor 1 (TAAR1), a G protein-coupled receptor (GPCR) that regulates brain catecholamine systems. Activation of TAAR1 increases cyclic adenosine monophosphate (cAMP) production and either completely inhibits or reverses the transport direction of the dopamine transporter (DAT), norepinephrine transporter (NET), and serotonin transporter (SERT). When methamphetamine binds to TAAR1, it triggers transporter phosphorylation via protein kinase A (PKA) and protein kinase C (PKC) signaling, ultimately resulting in the internalization or reverse function of monoamine transporters. Methamphetamine is also known to increase intracellular calcium, an effect which is associated with DAT phosphorylation through a Ca2+/calmodulin-dependent protein kinase (CAMK)-dependent signaling pathway, in turn producing dopamine efflux. TAAR1 has been shown to reduce the firing rate of neurons through direct activation of G protein-coupled inwardly-rectifying potassium channels. TAAR1 activation by methamphetamine in astrocytes appears to negatively modulate the membrane expression and function of EAAT2, a type of glutamate transporter.In addition to its effect on the plasma membrane monoamine transporters, methamphetamine inhibits synaptic vesicle function by inhibiting VMAT2, which prevents monoamine uptake into the vesicles and promotes their release. This results in the outflow of monoamines from synaptic vesicles into the cytosol (intracellular fluid) of the presynaptic neuron, and their subsequent release into the synaptic cleft by the phosphorylated transporters. Other transporters that methamphetamine is known to inhibit are SLC22A3 and SLC22A5. SLC22A3 is an extraneuronal monoamine transporter that is present in astrocytes, and SLC22A5 is a high-affinity carnitine transporter.Methamphetamine is also an agonist of the alpha-2 adrenergic receptors and sigma receptors with a greater affinity for σ1 than σ2, and inhibits monoamine oxidase A (MAO-A) and monoamine oxidase B (MAO-B). Sigma receptor activation by methamphetamine may facilitate its central nervous system stimulant effects and promote neurotoxicity within the brain. Dextromethamphetamine is a stronger psychostimulant, but levomethamphetamine has stronger peripheral effects, a longer half-life, and longer perceived effects among addicts. At high doses, both enantiomers of methamphetamine can induce similar stereotypy and methamphetamine psychosis, but levomethamphetamine has shorter psychodynamic effects.
Pharmacokinetics
The bioavailability of methamphetamine is 67% orally, 79% intranasally, 67 to 90% via inhalation (smoking), and 100% intravenously. Following oral administration, methamphetamine is well-absorbed into the bloodstream, with peak plasma methamphetamine concentrations achieved in approximately 3.13–6.3 hours post ingestion. Methamphetamine is also well absorbed following inhalation and following intranasal administration. Due to the high lipophilicity of methamphetamine, it can readily move through the blood–brain barrier faster than other stimulants, where it is more resistant to degradation by monoamine oxidase. The amphetamine metabolite peaks at 10–24 hours. Methamphetamine is excreted by the kidneys, with the rate of excretion into the urine heavily influenced by urinary pH. When taken orally, 30–54% of the dose is excreted in urine as methamphetamine and 10–23% as amphetamine. Following IV doses, about 45% is excreted as methamphetamine and 7% as amphetamine. The elimination half-life of methamphetamine varies with a range of 5–30 hours, however it is on average 9 to 12 hours in most studies. The elimination half-life of methamphetamine does not vary by route of administration, but is subject to substantial interindividual variability.CYP2D6, dopamine β-hydroxylase, flavin-containing monooxygenase 3, butyrate-CoA ligase, and glycine N-acyltransferase are the enzymes known to metabolize methamphetamine or its metabolites in humans. The primary metabolites are amphetamine and 4-hydroxymethamphetamine; other minor metabolites include: 4-hydroxyamphetamine, 4-hydroxynorephedrine, 4-hydroxyphenylacetone, benzoic acid, hippuric acid, norephedrine, and phenylacetone, the metabolites of amphetamine. Among these metabolites, the active sympathomimetics are amphetamine, 4‑hydroxyamphetamine, 4‑hydroxynorephedrine, 4-hydroxymethamphetamine, and norephedrine. Methamphetamine is a CYP2D6 inhibitor.The main metabolic pathways involve aromatic para-hydroxylation, aliphatic alpha- and beta-hydroxylation, N-oxidation, N-dealkylation, and deamination. The known metabolic pathways include:
Detection in biological fluids
Methamphetamine and amphetamine are often measured in urine or blood as part of a drug test for sports, employment, poisoning diagnostics, and forensics. Chiral techniques may be employed to help distinguish the source of the drug to determine whether it was obtained illicitly or legally via prescription or prodrug. Chiral separation is needed to assess the possible contribution of levomethamphetamine, which is an active ingredients in some OTC nasal decongestants, toward a positive test result. Dietary zinc supplements can mask the presence of methamphetamine and other drugs in urine.
Chemistry
Methamphetamine |
Methamphetamine | is a chiral compound with two enantiomers, dextromethamphetamine and levomethamphetamine. At room temperature, the free base of methamphetamine is a clear and colorless liquid with an odor characteristic of geranium leaves. It is soluble in diethyl ether and ethanol as well as miscible with chloroform.In contrast, the methamphetamine hydrochloride salt is odorless with a bitter taste. It has a melting point between 170 and 175 °C (338 and 347 °F) and, at room temperature, occurs as white crystals or a white crystalline powder. The hydrochloride salt is also freely soluble in ethanol and water. Its crystal structure is monoclinic with P21 space group; at 90 K (−183.2 °C; −297.7 °F), it has lattice parameters a = 7.10 Å, b = 7.29 Å, c = 10.81 Å, and β = 97.29°.
Degradation
A 2011 study into the destruction of methamphetamine using bleach showed that effectiveness is correlated with exposure time and concentration. A year-long study (also from 2011) showed that methamphetamine in soils is a persistent pollutant. In a 2013 study of bioreactors in wastewater, methamphetamine was found to be largely degraded within 30 days under exposure to light.
Synthesis
Racemic methamphetamine may be prepared starting from phenylacetone by either the Leuckart or reductive amination methods. In the Leuckart reaction, one equivalent of phenylacetone is reacted with two equivalents of N-methylformamide to produce the formyl amide of methamphetamine plus carbon dioxide and methylamine as side products. In this reaction, an iminium cation is formed as an intermediate which is reduced by the second equivalent of N-methylformamide. The intermediate formyl amide is then hydrolyzed under acidic aqueous conditions to yield methamphetamine as the final product. Alternatively, phenylacetone can be reacted with methylamine under reducing conditions to yield methamphetamine.
History, society, and culture
Amphetamine, discovered before methamphetamine, was first synthesized in 1887 in Germany by Romanian chemist Lazăr Edeleanu who named it phenylisopropylamine. Shortly after, methamphetamine was synthesized from ephedrine in 1893 by Japanese chemist Nagai Nagayoshi. Three decades later, in 1919, methamphetamine hydrochloride was synthesized by pharmacologist Akira Ogata via reduction of ephedrine using red phosphorus and iodine.
Since 1938, methamphetamine was marketed on a large scale in Germany as a nonprescription drug under the brand name Pervitin, produced by the Berlin-based Temmler pharmaceutical company. It was used by all branches of the combined armed forces of the Third Reich, for its stimulant effects and to induce extended wakefulness. Pervitin became colloquially known among the German troops as "Stuka-Tablets" (Stuka-Tabletten) and "Herman-Göring-Pills" (Hermann-Göring-Pillen), as a snide allusion to Görings widely-known addiction to drugs. However, the side effects, particularly the withdrawal symptoms, were so serious that the army sharply cut back its usage in 1940. By 1941, usage was restricted to a doctors prescription, and the military tightly controlled its distribution. Soldiers would only receive a couple of tablets at a time, and were discouraged from using them in combat. Historian Łukasz Kamieński says, "A soldier going to battle on Pervitin usually found himself unable to perform effectively for the next day or two. Suffering from a drug hangover and looking more like a zombie than a great warrior, he had to recover from the side effects." Some soldiers turned violent, committing war crimes against civilians; others attacked their own officers.At the end of the war, it was used as part of a new drug: D-IX.
Obetrol, patented by Obetrol Pharmaceuticals in the 1950s and indicated for treatment of obesity, was one of the first brands of pharmaceutical methamphetamine products. Due to the psychological and stimulant effects of methamphetamine, Obetrol became a popular diet pill in America in the 1950s and 1960s. Eventually, as the addictive properties of the drug became known, governments began to strictly regulate the production and distribution of methamphetamine. For example, during the early 1970s in the United States, methamphetamine became a schedule II controlled substance under the Controlled Substances Act. Currently, methamphetamine is sold under the trade name Desoxyn, trademarked by the Danish pharmaceutical company Lundbeck. As of January 2013, the Desoxyn trademark had been sold to Italian pharmaceutical company Recordati.
Trafficking
The Golden Triangle (Southeast Asia), specifically Shan State, Myanmar, is the worlds leading producer of methamphetamine as production has shifted to Yaba and crystalline methamphetamine, including for export to the United States and across East and Southeast Asia and the Pacific.Concerning the accelerating synthetic drug production in the region, the Cantonese Chinese syndicate Sam Gor, also known as The Company, is understood to be the main international crime syndicate responsible for this shift. It is made up of members of five different triads. Sam Gor is primarily involved in drug trafficking, earning at least $8 billion per year. Sam Gor is alleged to control 40% of the Asia-Pacific methamphetamine market, while also trafficking heroin and ketamine. The organization is active in a variety of countries, including Myanmar, Thailand, New Zealand, Australia, Japan, China, and Taiwan. Sam Gor previously produced meth in Southern China and is now believed to manufacture mainly in the Golden Triangle, specifically Shan State, Myanmar, responsible for much of the massive surge of crystal meth in recent years. The group is understood to be headed by Tse Chi Lop, a gangster born in Guangzhou, China who also holds a Canadian passport.
Liu Zhaohua was another individual involved in the production and trafficking of methamphetamine until his arrest in 2005. It was estimated over 18 tonnes of methamphetamine were produced under his watch.
Legal status
The production, distribution, sale, and possession of methamphetamine is restricted or illegal in many jurisdictions. Methamphetamine has been placed in schedule II of the United Nations Convention on Psychotropic Substances treaty.
Research
It has been suggested, based on animal research, that calcitriol, the active metabolite of vitamin D, can provide significant protection against the DA- and 5-HT-depleting effects of neurotoxic doses of methamphetamine.
See also
18-MC
Breaking Bad, a TV drama series centered on illicit methamphetamine synthesis
Drug checking
Faces of Meth, a drug prevention project
Harm reduction
Methamphetamine in Australia
Methamphetamine in Bangladesh
Methamphetamine in the Philippines
Methamphetamine in the United States
Montana Meth Project, a Montana-based organization aiming to reduce meth use among teenagers
Recreational drug use
Rolling meth lab, a transportable laboratory that is used to illegally produce methamphetamine
Ya ba, Southeast Asian tablets containing a mixture of methamphetamine and caffeine
Explanatory notes
Image legend
Reference notes
References
Further reading
Szalavitz M. "Why the Myth of the Meth-Damaged Brain May Hinder Recovery". Time.com. Time USA, LLC.
Hart CL, Marvin CB, Silver R, Smith EE (February 2012). "Is cognitive functioning impaired in methamphetamine users? A critical review". Neuropsychopharmacology. 37 (3): 586–608. doi:10.1038/npp.2011.276. ISSN 0893-133X. PMC 3260986. PMID 22089317.
Maia Szalavitz (21 November 2011). "Why the Myth of the Meth-Damaged Brain May Hinder Recovery". Time.
External links
Methamphetamine Toxnet entry
Methamphetamine Poison Information Monograph
Drug Trafficking: Aryan Brotherhood Methamphetamine Operation Dismantled, FBI
Neurologic manifestations of chronic methamphetamine abuse |
Fexofenadine/pseudoephedrine | Fexofenadine/pseudoephedrine, sold under the brand name Allegra-D among others, is a fixed-dose combination medication used for the treatment of nasal congestion and other symptoms of allergies and the common cold. It contains fexofenadine, as the hydrochloride, an antihistamine; and pseudoephedrine, as the hydrochloride, a nasal decongestant.In 2019, it was the 380th most commonly prescribed medication in the United States, with more than 500 thousand prescriptions.
References
External links
"Fexofenadine hydrochloride". Drug Information Portal. U.S. National Library of Medicine.
"Pseudoephedrine hydrochloride". Drug Information Portal. U.S. National Library of Medicine. |
Sacituzumab govitecan | Sacituzumab govitecan, sold under the brand name Trodelvy, is a Trop-2-directed antibody and topoisomerase inhibitor drug conjugate used for the treatment of metastatic triple-negative breast cancer and metastatic urothelial cancer.The most common side effects include nausea, neutropenia, diarrhea, fatigue, anemia, vomiting, alopecia (hair loss), constipation, decreased appetite, rash and abdominal pain. Sacituzumab govitecan has a boxed warning about the risk of severe neutropenia (abnormally low levels of white blood cells) and severe diarrhea. Sacituzumab govitecan may cause harm to a developing fetus or newborn baby. Women are advised not to breastfeed while on sacituzumab govitecan and one month after the last dose is administered.The U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) consider it to be a first-in-class medication. Sacituzumab govitecan was approved for medical use in the European Union in November 2021.
Medical uses
Sacituzumab govitecan is indicated for the treatment of adults with metastatic triple-negative breast cancer who received at least two prior therapies for metastatic disease; people with unresectable locally advanced or metastatic triple-negative breast cancer (mTNBC) who have received two or more prior systemic therapies, at least one of them for metastatic disease; and for people with locally advanced or metastatic urothelial cancer (mUC) who previously received a platinum-containing chemotherapy and either a programmed death receptor-1 (PD-1) or a programmed death-ligand 1 (PD-L1) inhibitor.
Administration
Sacituzumab govitecan is given in a 21-day treatment cycle in which an injection is only given a few days of the cycle. It is given slowly from one to three hours under the supervision of a physician.
Mechanism
Sacituzumab govitecan is a conjugate of the humanized anti-Trop-2 monoclonal antibody linked with SN-38, the active metabolite of irinotecan. Each antibody having on average 7.6 molecules of SN-38 attached. SN-38 is too toxic to administer directly to patients, but linkage to an antibody allows the drug to specifically target cells containing Trop-2.Sacituzumab govitecan is a Trop-2-directed antibody and topoisomerase inhibitor drug conjugate, meaning that the drug targets the Trop-2 receptor that helps the cancer grow, divide and spread, and is linked to topoisomerase inhibitor, which is a chemical compound that is toxic to cancer cells. Approximately two of every ten breast cancer diagnoses worldwide are triple-negative. Triple-negative breast cancer is a type of breast cancer that tests negative for estrogen receptors, progesterone receptors and human epidermal growth factor receptor 2 (HER2) protein. Therefore, triple-negative breast cancer does not respond to hormonal therapy medicines or medicines that target HER2.
Development
Immunomedics announced in 2013, that it had received fast track designation from the US Food and Drug Administration (FDA) for the compound as a potential treatment for non-small cell lung cancer, small cell lung cancer, and metastatic triple-negative breast cancer. Orphan drug status was granted for small cell lung cancer and pancreatic cancer. In February 2016, Immunomedics announced that sacituzumab govitecan had received an FDA breakthrough therapy designation (a classification designed to expedite the development and review of drugs that are intended, alone or in combination with one or more other drugs, to treat a serious or life-threatening disease or condition) for the treatment of people with triple-negative breast cancer who have failed at least two other prior therapies for metastatic disease.
History
Sacituzumab govitecan was added to the proposed International nonproprietary name (INN) list in 2015, and to the recommended list in 2016.Sacituzumab govitecan-hziy was approved for medical use in the United States in April 2020.Sacituzumab govitecan-hziy was approved based on the results of IMMU-132-01, a multicenter, single-arm clinical trial (NCT01631552) of 108 participants with metastatic triple-negative breast cancer who had received at least two prior treatments for metastatic disease. Of the 108 participants involved within the study, 107 were female and 1 was male. Participants received sacituzumab govitecan-hziy at a dose of 10 milligrams per kilogram of body weight intravenously on days one and eight every 21 days. Treatment with sacituzumab govitecan-hziy was continued until disease progression or unacceptable toxicity. Tumor imaging was obtained every eight weeks. The efficacy of sacituzumab govitecan-hziy was based on the overall response rate (ORR) – which reflects the percentage of participants that had a certain amount of tumor shrinkage. The ORR was 33.3% (95% confidence interval [CI], 24.6 to 43.1). Additionally, with the 33.3% of study participants who achieved a response, 2.8% of participants experienced complete responses. The median time to response in participants was 2.0 months (range, 1.6 to 13.5), the median duration of response was 7.7 months (95% confidence interval [CI], 4.9 to 10.8), the median progression free survival was 5.5 months, and the median overall survival was 13.0 months. Of the participants that achieved an objective response to sacituzumab govitecan-hziy, 55.6% maintained their response for six or more months and 16.7% maintained their response for twelve or more months.Sacituzumab govitecan-hziy was granted accelerated approval along with priority review, breakthrough therapy, and fast track designations. The U.S. Food and Drug Administration (FDA) granted approval of Trodelvy to Immunomedics, Inc.In April 2021, the FDA granted regular approval to sacituzumab govitecan for people with unresectable locally advanced or metastatic triple-negative breast cancer (mTNBC) who have received two or more prior systemic therapies, at least one of them for metastatic disease. Efficacy and safety were evaluated in a multicenter, open-label, randomized trial (ASCENT; NCT02574455) conducted in 529 participants with unresectable locally advanced or mTNBC who had relapsed after at least two prior chemotherapies, one of which could be in the neoadjuvant or adjuvant setting, if progression occurred within twelve months. Participants were randomized (1:1) to receive sacituzumab govitecan, 10 mg/kg as an intravenous infusion, on days 1 and 8 of a 21-day (n=267) cycle or physicians choice of single agent chemotherapy (n=262).In April 2021, the FDA granted accelerated approval to sacituzumab govitecan for people with locally advanced or metastatic urothelial cancer (mUC) who previously received a platinum-containing chemotherapy and either a programmed death receptor-1 (PD-1) or a programmed death-ligand 1 (PD-L1) inhibitor. Efficacy and safety were evaluated in TROPHY (IMMU-132-06; NCT03547973), a single-arm, multicenter trial that enrolled 112 participants with locally advanced or mUC who received prior treatment with a platinum-containing chemotherapy and either a PD-1 or PD-L1 inhibitor.
Society and culture
Legal status
On 14 October 2021, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Trodelvy, intended for the treatment of unresectable or metastatic triple-negative breast cancer. The applicant for this medicinal product is Gilead Sciences Ireland UC. Sacituzumab govitecan was approved for medical use in the European Union in November 2021.
References
Further reading
Bardia A, Mayer IA, Vahdat LT, Tolaney SM, Isakoff SJ, Diamond JR, et al. (February 2019). "Sacituzumab Govitecan-hziy in Refractory Metastatic Triple-Negative Breast Cancer". N. Engl. J. Med. 380 (8): 741–751. doi:10.1056/NEJMoa1814213. PMID 30786188.
Weiss J, Glode A, Messersmith WA, Diamond J (August 2019). "Sacituzumab govitecan: breakthrough targeted therapy for triple-negative breast cancer". Expert Rev Anticancer Ther. 19 (8): 673–79. doi:10.1080/14737140.2019.1654378. PMID 31398063. S2CID 199518147.
External links
"Sacituzumab govitecan". Drug Information Portal. U.S. National Library of Medicine.
"Sacituzumab govitecan". ADC Review.
"Sacituzumab govitecan". National Cancer Institute.
Clinical trial number NCT01631552 for "Phase I/II Study of IMMU-132 in Patients With Epithelial Cancers" at ClinicalTrials.gov
Clinical trial number NCT02574455 for "ASCENT-Study of Sacituzumab Govitecan in Refractory/Relapsed Triple-Negative Breast Cancer (ASCENT)" at ClinicalTrials.gov
Clinical trial number NCT03547973 for "Phase II Open Label, Study of IMMU-132 in Metastatic Urothelial Cancer" at ClinicalTrials.gov
Sacituzumab govitecan at the US National Library of Medicine Medical Subject Headings (MeSH) |
Alosetron | Alosetron, sold under the brand name Lotronex among others, is a 5-HT3 antagonist used for the management of severe diarrhea-predominant irritable bowel syndrome (IBS) in women only.
It was patented in 1987 and approved for medical use in 2002. It is currently marketed by Prometheus Laboratories Inc. (San Diego). Alosetron was withdrawn from the market in 2000 owing to the occurrence of serious life-threatening gastrointestinal adverse effects, but was reintroduced in 2002 with availability and use restricted.
Medical uses
Alosetron is indicated only for women with severe diarrhea-predominant irritable bowel syndrome (IBS-D) who have:
chronic IBS symptoms (generally lasting 6 months or longer),
had anatomic or biochemical abnormalities of the gastrointestinal tract excluded, and
not responded adequately to conventional therapy.Severe IBS-D includes: diarrhea and 1 or more of the following:
frequent and severe abdominal pain/discomfort,
frequent bowel urgency or fecal incontinence,
disability or restriction of daily activities due to IBS.
Efficacy
The phase III trial for approval was published in 2000 as an industry-funded randomised, placebo-controlled trial (PCT). Its authors found 1 mg alosetron, taken orally twice daily for 12 weeks, was associated with a 12% (CI 4.7-19.2) improvement in relief from abdominal pain and discomfort associated with diarrhoea-predominant patients. The prescription of alosetron is currently approved in the U.S. at 0.5 and 1 mg.The FDA Medical Officers Review, dated November 4, 1999, noted: "Patients considered by investigators to fit the diarrhea-predominant subtype had at baseline... stool consistency values that were neither loose nor watery". The FDAs Gastrointestinal Drugs Advisory Committee referred to the drugs efficacy as "modest", highlighting that the placebo brought relief on the primary outcome measure to 40–50% of women.
Contraindications
Lotronexs prescribing information brochure states that alosetron should not be initiated in patients with constipation. Other contraindications are: history of chronic or severe constipation or sequelae from constipation; intestinal obstruction, stricture, toxic megacolon, gastrointestinal perforation, and/or adhesions, ischemic colitis, impaired intestinal circulation, thrombophlebitis, or hypercoagulable state; Crohns disease or ulcerative colitis; diverticulitis; severe hepatic impairment. Concomitant use of fluvoxamine is also contraindicated.
Adverse effects
Alosetron was withdrawn in 2000 following the association of alosetron with serious life-threatening gastrointestinal adverse effects. The cumulative incidence of ischaemic colitis was 2 in 1000, while serious complications arising from constipation (obstruction, perforation, impaction, toxic megacolon, secondary colonic ischaemia, death) was 1 in 1000. A 1999 review performed by FDA medical officer John Senior, indicated that 27% of patients experienced constipation. The phase III trial reported constipation occurred in 30% and 3% of patients in the alosetron and placebo groups, respectively. It was cited as the most important reason for patients dropping out of the study.
Mechanism of action
Alosetron has an antagonist action on the 5-HT3 receptors of the enteric nervous system of the gastrointestinal tract. While being a 5-HT3 antagonist like ondansetron, it is not classified or approved as an antiemetic. Since stimulation of 5-HT3 receptors is positively correlated with gastrointestinal motility, alosetrons 5-HT3 antagonism slows the movement of fecal matter through the large intestine, increasing the extent to which water is absorbed, and decreasing the moisture and volume of the remaining waste products.
History
Alosetron was originally approved by the U.S. Food and Drug Administration (FDA) on February 9, 2000, after a seven-month review. At the time of the initial approval U.S. Food and Drug Administration (FDA) reviewers found that alosetron improved symptoms in 10% to 20% of patients.Shipment to pharmacies started in March, 2000. On July 17, a health professional filed a report with the FDA on the death of a 50-year-old woman who suffered mesenteric ischemia. The report identified alosetron as the "primary suspect" in the death.Alosetron was withdrawn from the market voluntarily by GlaxoWellcome on November 28, 2000 owing to the occurrence of serious life-threatening gastrointestinal adverse effects, including 5 deaths and additional bowel surgeries. The FDA said it had reports of 49 cases of ischemic colitis and 21 cases of "severe constipation" and that ten of the 70 patients underwent surgeries and 34 others were examined at hospitals and released without surgery. Through November 17, 2000, pharmacists had filled 474,115 prescriptions for alosetron. Severe adverse events continued to be reported, with a final total of 84 instances of ischaemic colitis, 113 of severe constipation, 143 admissions to hospital, and 7 deaths.Patient advocacy groups, most notably the Lotronex Action Group and the International Foundation for Functional Gastrointestinal Disorders (IFFGD) lobbied for the drugs return. Public Citizen Health Research Group, another patient advocacy group, opposed the reintroduction.On June 7, 2002, the FDA announced the approval of a supplemental New Drug Application (sNDA) that allows restricted marketing of Lotronex (alosetron hydrochloride), to treat only women with severe diarrhea-predominant irritable bowel syndrome (IBS). The strict prescribing guidelines initially introduced in 2002 were relaxed slightly in 2016, enabling electronic prescriptions among other benefits.
It is not known whether alosetron has been filed for registration in the EU.
GSK sold Lotronex to the Californian corporation Prometheus in late 2007.Since 2015, generic versions of alosetron have been available in the US, sold by a number of different companies including Actavis Pharma Company, Prometheus Laboratories and Sebela Pharmaceuticals Inc
Criticism of the FDA
In 2001, the editor of the renowned medical journal The Lancet, Richard Horton, criticized the FDAs handling of alosetron in an unusually sharp language. Horton argued that the treatment of a non-fatal condition did not justify the use of a drug with potentially lethal side effects, and that the FDA should have revoked the approval for alosetron sooner when postmarketing surveillance revealed that many patients had suffered constipation necessitating surgical intervention and ischaemic colitis. He asserted that FDA officials were improperly motivated to maintain and reinstate the approval for alosetron because of the extent to which the FDAs Center for Drug Evaluation and Research is funded by user fees paid by pharmaceutical manufacturers, and that the reinstatement of alosetron was negotiated in confidential meetings with representatives of GlaxoSmithKline.
An article published in the British Medical Journal (BMJ) noted: "By allowing the marketing of alosetron, a drug that poses a serious and significant public health concern according to its own terms, the FDA failed in its mission." Others have argued that the approval process of Lotronex was an example of regulatory capture.
== References == |
Rabies vaccine | The rabies vaccine is a vaccine used to prevent rabies. There are a number of rabies vaccines available that are both safe and effective. They can be used to prevent rabies before, and, for a period of time, after exposure to the rabies virus, which is commonly caused by a dog bite or a bat bite.Doses are usually given by injection into the skin or muscle. After exposure, the vaccination is typically used along with rabies immunoglobulin. It is recommended that those who are at high risk of exposure be vaccinated before potential exposure. Rabies vaccines are effective in humans and other animals, and vaccinating dogs is very effective in preventing the spread of rabies to humans. A long-lasting immunity to the virus develops after a full course of treatment.Rabies vaccines may be used safely by all age groups. About 35 to 45 percent of people develop a brief period of redness and pain at the injection site, and 5 to 15 percent of people may experience fever, headaches, or nausea. After exposure to rabies, there is no contraindication to its use, because the untreated virus is overwhelmingly fatal.The first rabies vaccine was introduced in 1885 and was followed by an improved version in 1908. Millions of people globally are vaccinated against the virus. It is on the World Health Organizations List of Essential Medicines.
Medical uses
Before exposure
The World Health Organization (WHO) recommends vaccinating those who are at high risk of the disease, such as children who live in areas where it is common. Other groups may include veterinarians, researchers, or people planning to travel to regions where rabies is common. Three doses of the vaccine are given over a one-month period on days zero, seven, and either twenty-one or twenty-eight.
After exposure
For individuals who have been potentially exposed to the virus, four doses over two weeks are recommended, as well as an injection of rabies immunoglobulin with the first dose. This is known as post-exposure vaccination. For people who have previously been vaccinated, only a single dose of the rabies vaccine is required. However, vaccination after exposure is neither a treatment nor a cure for rabies; it can only prevent the development of rabies in a person if given before the virus reaches the brain. Because the rabies virus has a relatively long incubation period, post-exposure vaccinations are typically highly effective.
Additional doses
Immunity following a course of doses is typically long lasting, and additional doses are usually not needed unless the person has a high risk of contracting the virus. Those at risk may have tests done to measure the amount of rabies antibodies in the blood, and then get rabies boosters as needed. Following administration of a booster dose, one study found 97% of immunocompetent individuals demonstrated protective levels of neutralizing antibodies after ten years.
Safety
Rabies vaccines are safe in all age groups. About 35 to 45 percent of people develop a brief period of redness and pain at the injection site, and 5 to 15 percent of people may experience fever, headaches, or nausea. Because of the certain fatality of the virus, receiving the vaccine is always advisable.Vaccines made from nerve tissue are used in a few countries, mainly in Asia and Latin America, but are less effective and have greater side effects. Their use is thus not recommended by the World Health Organization.
Types
The human diploid cell rabies vaccine (H.D.C.V.) was started in 1967. Human diploid cell rabies vaccines are inactivated vaccines made using the attenuated Pitman-Moore L503 strain of the virus.In addition to these developments, newer and less expensive purified chicken embryo cell vaccines (CCEEV) and purified Vero cell rabies vaccines are now available and are recommended for use by the WHO. The purified Vero cell rabies vaccine uses the attenuated Wistar strain of the rabies virus, and uses the Vero cell line as its host. CCEEVs can be used in both pre- and post-exposure vaccinations. CCEEVs use inactivated rabies virus grown from either embryonated eggs or in cell cultures and are safe for use in humans and animals.The vaccine was attenuated and prepared in the H.D.C. strain WI-38 which was gifted to Dr. Hilary Koprowski at the Wistar Institute by Dr. Leonard Hayflick, an Associate Member, who developed this normal human diploid cell strain.
History
Virtually all infections with rabies resulted in death until two French scientists, Louis Pasteur and Émile Roux, developed the first rabies vaccination in 1885. Nine-year-old Joseph Meister (1876–1940), who had been mauled by a rabid dog, was the first human to receive this vaccine. The treatment started with a subcutaneous injection on 6 July 1885, at 8:00 pm, which was followed with 12 additional doses administered over the following 10 days. The first injection was derived from the spinal cord of an inoculated rabbit which had died of rabies 15 days earlier. All the doses were obtained by attenuation, but later ones were progressively more virulent.The Pasteur-Roux vaccine attenuated the harvested virus samples by allowing them to dry for five to ten days. Similar nerve tissue-derived vaccines are still used in some countries, and while they are much cheaper than modern cell culture vaccines, they are not as effective. Neural tissue vaccines also carry a certain risk of neurological complications.
Cost
When the modern cell-culture rabies vaccine was first introduced in the early 1980s, it cost $45 per dose, and was considered to be too expensive. The cost of the rabies vaccine continues to be a limitation to acquiring pre-exposure rabies immunization for travelers from developed countries. In 2015 in the United States, a course of three doses could cost over $1,000, while in Europe a course costs around €100. It is possible and more cost-effective to split one intramuscular dose of the vaccine into several intradermal doses. This method is recommended by the World Health Organisation in areas that are constrained by cost or with supply issues. The route is as safe and effective as intramuscular according to the WHO.
Veterinary use
Pre-exposure immunization has been used on domesticated and wild populations. In many jurisdictions, domestic dogs, cats, ferrets, and rabbits are required to be vaccinated.There are two main types of vaccines used for domesticated animals and pets (including pets from wildlife species):
Inactivated rabies virus (similar technology to that given to humans) administered by injection
Modified live viruses administered orally (by mouth): Live rabies virus from attenuated strains. Attenuated means strains that have developed mutations that cause them to be weaker and do not cause disease.Imrab is an example of a veterinary rabies vaccine containing the Pasteur strain of killed rabies virus. Several different types of Imrab exist, including Imrab, Imrab 3, and Imrab Large Animal. Imrab 3 has been approved for ferrets and, in some areas, pet skunks.
Dogs
Aside from vaccinating humans, another approach was also developed by vaccinating dogs to prevent the spread of the virus. In 1979, the Van Houweling Research Laboratory of the Silliman University Medical Center in Dumaguete in the Philippines developed and produced a dog vaccine that gave a three-year immunity from rabies. The development of the vaccine resulted in the elimination of rabies in many parts of the Visayas and Mindanao Islands. The successful program in the Philippines was later used as a model by other countries, such as Ecuador and the Yucatan State of Mexico, in their fight against rabies conducted in collaboration with the World Health Organization.In Tunisia, a rabies control program was initiated to give dog owners free vaccination to promote mass vaccination which was sponsored by their government. The vaccine is known as Rabisin (Mérial), which is a cell based rabies vaccine only used countrywide. Vaccinations are often administered when owners take in their dogs for check-ups and visits at the vet.Oral rabies vaccines (see below for details) have been trialled on feral/stray dogs in some areas with high rabies incidence, as it could potentially be more efficient than catching and injecting them. However these have not been deployed for dogs at large scale yet.
Wild animals
Wildlife species, primarily bats, raccoons, skunks, and foxes, act as reservoir species for different variants of the rabies virus. This results in the general occurrence of rabies as well as outbreaks in animal populations. Approximately 90% of all reported rabies cases in the US are from wildlife.
Oral rabies vaccine
Oral rabies vaccines in pellet form are intended to be given to wild animals to produce a herd immunity effect. The development of safe and effective rabies virus vaccines applied in attractive baits resulted in the first field trials in Switzerland in 1978 to immunize red foxes.There are currently two different types of oral wildlife rabies vaccine in use:
Modified live virus: Attenuated vaccine strains of rabies virus such as SAG2 and SAD B19
Recombinant vaccinia virus expressing rabies glycoprotein: This is a strain of the vaccinia virus (originally a smallpox vaccine) that has been engineed to encode the gene for the rabies glycoprotein. It is mostly used in the USA (raccoons, foxes, and coyotes) and in western Europe (red foxes)Other oral rabies experimental vaccines in development include recombinant adenovirus vaccines.
Oral rabies vaccination (ORV) programs have been used in many countries in an effort to control the spread of rabies and limit the risk of human contact with the rabies virus. ORV programs were initiated in Europe in the 1980s, Canada in 1985, and in the United States in 1990. ORV is a preventive measure to eradicate rabies in wild animal vectors of disease, mainly foxes, raccoons, raccoon dogs, coyotes and jackals, but also can be used for dogs in developing countries. ORV programs typically use edible baits to deliver the vaccine to targeted animals. ORV baits consist of a small packet containing the oral vaccine which is then either coated in a fishmeal paste or encased in a fishmeal-polymer block. When an animal bites into the bait, the packets burst and the vaccine is administered. Current research suggests that if adequate amounts of the vaccine is ingested, immunity to the virus should last for upwards of one year. By immunizing wild or stray animals, ORV programs work to create a buffer zone between the rabies virus and potential contact with humans, pets, or livestock. The effectiveness of ORV campaigns in specific areas is determined through trap-and-release methods. Titer tests are performed on the blood drawn from the sample animals in order to measure rabies antibody levels in the blood. Baits are usually distributed by aircraft to more efficiently cover large, rural regions. In order to place baits more precisely and to minimize human and pet contact with baits, however, they are distributed by hand in suburban or urban regions.ORV programs have seen success in preventing the westward spread of raccoon variant rabies in the United States and even eradicating rabies in red foxes in Switzerland.The oral vaccine does not contain the whole rabies virus and has been proven safe in over 60 animal species including cats and dogs. The idea of wildlife vaccination was conceived during the 1960s, and modified-live rabies viruses were used for the experimental oral vaccination of carnivores by the 1970s. The potential for human contact with baits is a present concern for ORV programs, but the inactivated rabies vaccine cannot cause rabies, and the recombinant poxvirus vaccine is based on an attenuated poxvirus which is unlikely to cause serious disease in humans anyway. In the USA between 1990 and 2000, over 22 million doses of vaccinia-rabies were distributed, but there were only 160 incidents of people touching a vaccine bait, and only one resulted in a serious infection. The person in this case had been bitten by her dog while removing a bait from its mouth.
References
External links
"Rabies Vaccine Information Statement". U.S. Centers for Disease Control and Prevention (CDC). 9 April 2021.
"Imovax". U.S. Food and Drug Administration (FDA). 16 December 2019. STN: 103931.
"RabAvert - Rabies Vaccine". U.S. Food and Drug Administration (FDA). 12 December 2019. STN: BL 103334.
Rabies Vaccines at the US National Library of Medicine Medical Subject Headings (MeSH) |
Endo International | Endo International plc is an American Irish-domiciled generics and specialty branded pharmaceutical company that generated over 93% of its 2017 sales from the U.S. healthcare system. While Endos management, operations, and customers are almost exclusively U.S.–based, in 2013 Endo executed a corporate tax inversion to Ireland to avoid U.S. corporate taxes on their U.S. drug sales, and to avail of Irelands corporate tax system.
History and Acquisitions
Endo was created as a result of a management buyout from DuPont Merck in 1997 led by Carol Ammon.In 2009, Endo bought Indevus Pharmaceuticals to diversify into endocrinology and oncology. The company entered the male hypogonadism market later in 2010 with Fortesta 2% gel. In November 2013, Endo agreed to purchase Paladin Labs Inc for about $1.6 billion to gain access to the Canadian market as well as expand into emerging markets.Endo used the 2013 acquisition of Paladin Labs, and Canadian tax laws, to execute a corporate tax inversion to Ireland. In July 2015, The Wall Street Journal noted Endo was using Irelands lower tax rate to acquire U.S.–based life sciences firms and relocate them to Irelands tax regime (i.e. they could afford to pay more to acquire U.S. competitors).In October 2014, Endo said it would buy Auxilium Pharmaceuticals for $2.6 billion along with its testosterone replacement therapy products.In 2015, Endo acquired the specialty generics and sterile injectables company Par Pharmaceutical for $8.05 billion.In 2018, Endo settled over 1,200 lawsuits related to its testosterone replacement therapy, Testim, and its undisclosed side effects.
Acquisition attempts
In early 2014, Endo sought to acquire NuPathe, a speciality pharmaceutical developer, for $105 million. However, Teva prevailed in this acquisition with a substantially higher bid.
Bankruptcy
In 2022, Endos stock fell below $1 as the company faced restructuring of its $8 billion of debt.
On August 17, 2022 Endo International Plc filed for Chapter 11 bankruptcy protection after reaching a $6 billion deal with some of its creditors.
Opioids
Endo is one of the companies named in lawsuits by the states of Ohio, Missouri and Mississippi as responsible for the US opioid epidemic. Its 10-K statement indicates that a majority of the companys US revenue in 2016 was derived from the sale of prescription pain killers, predominantly opioids.On June 8, 2017, the U.S. Food and Drug Administration (FDA) released a press statement in which it announced that it requested Endo to withdraw its opioid drug, oxymorphone hydrochloride (Opana ER), from the market. Opana has been linked to outbreaks of HIV, hepatitis C and serious blood disorders. It was the first time that the FDA had "taken steps to remove a currently marketed opioid pain medication from sale due to the public health consequences of abuse."In 2021, New York Attorney General Letitia James filed a lawsuit against Endo and several other opioid manufacturers for their alleged contribution to the opioid epidemic in New York.
See also
Opioid epidemic
Corporate tax inversions
Ireland as a tax haven
References
External links
Official website |
Allopurinol | Allopurinol is a medication used to decrease high blood uric acid levels. It is specifically used to prevent gout, prevent specific types of kidney stones and for the high uric acid levels that can occur with chemotherapy. It is taken by mouth or injected into a vein.Common side effects when used by mouth include itchiness and rash. Common side effects when used by injection include vomiting and kidney problems. While not recommended historically, starting allopurinol during an attack of gout appears to be safe. In those already on the medication, it should be continued even during an acute gout attack. While use during pregnancy does not appear to result in harm, this use has not been well studied. Allopurinol is in the xanthine oxidase inhibitor family of medications.Allopurinol was approved for medical use in the United States in 1966. It is on the World Health Organizations List of Essential Medicines. Allopurinol is available as a generic medication. In 2020, it was the 42nd most commonly prescribed medication in the United States, with more than 15 million prescriptions.
Medical uses
Gout
Allopurinol is used to reduce urate formation in conditions where urate deposition has already occurred or is predictable. The specific diseases and conditions where it is used include gouty arthritis, skin tophi, kidney stones, idiopathic gout; uric acid lithiasis; acute uric acid nephropathy; neoplastic disease and myeloproliferative disease with high cell turnover rates, in which high urate levels occur either spontaneously, or after cytotoxic therapy; certain enzyme disorders which lead to overproduction of urate, for example: hypoxanthine-guanine phosphoribosyltransferase, including Lesch–Nyhan syndrome; glucose 6-phosphatase including glycogen storage disease; phosphoribosyl pyrophosphate synthetase, phosphoribosyl pyrophosphate amidotransferase; adenine phosphoribosyltransferase.
It is also used to treat kidney stones caused by deficient activity of adenine phosphoribosyltransferase.
Tumor lysis syndrome
Allopurinol was also commonly used to treat tumor lysis syndrome in chemotherapeutic treatments, as these regimens can rapidly produce severe acute hyperuricemia; however, it has gradually been replaced by urate oxidase therapy. Intravenous formulations are used in this indication when people cannot take medicine by mouth.
Inflammatory bowel disease
Allopurinol cotherapy is used to improve outcomes for people with inflammatory bowel disease and Crohns disease who do not respond to thiopurine monotherapy. Cotherapy has also been shown to greatly improve hepatoxicity side effects in treatment of IBD. Cotherapy invariably requires dose reduction of the thiopurine, usually to one-third of the standard dose depending upon the patients genetic status for thiopurine methyltransferase.
Psychiatric disorders
Allopurinol has been tested as an augmentation strategy for the treatment of mania in bipolar disorder. Meta-analytic evidence showed that adjunctive allopurinol was superior to placebo for acute mania (both with and without mixed features). Its efficacy was not influenced by dosage, follow-up duration, or concurrent standard treatment.
Cardiovascular disease
There is a correlation between uric acid levels and cardiovascular disease and mortality, and so allopurinol has been explored as a potential treatment to reduce risk of cardiac disease. However, the data is inconsistent and conflicting, and the use of allopurinol for use in cardiovascular disease is controversial. Independently of its effects on uric acid, it may also have effects on oxidative stress and inflammation.
Side effects
Because allopurinol is not a uricosuric, it can be used in people with poor kidney function. However, for people with impaired kidney function, allopurinol has two disadvantages. First, its dosing is complex. Second, some people are hypersensitive to the drug; therefore, its use requires careful monitoring.Allopurinol has rare but potentially fatal adverse effects involving the skin. The most serious adverse effect is a hypersensitivity syndrome consisting of fever, skin rash, eosinophilia, hepatitis, and worsened renal function, collectively referred to as DRESS syndrome. Allopurinol is one of the drugs commonly known to cause Stevens–Johnson syndrome and toxic epidermal necrolysis, two life-threatening dermatological conditions. More common is a less-serious rash that leads to discontinuing this drug.More rarely, allopurinol can also result in the depression of bone marrow elements, leading to cytopenias, as well as aplastic anemia. Moreover, allopurinol can also cause peripheral neuritis in some patients, although this is a rare side effect. Another side effect of allopurinol is interstitial nephritis.
Drug interactions
Drug interactions are extensive, and are as follows:
Azathioprine and 6-mercaptopurine: Azathioprine is metabolised to 6-mercaptopurine which in turn is inactivated by the action of xanthine oxidase - the target of allopurinol. Giving allopurinol with either of these drugs at their normal dose will lead to overdose of either drug; only one-quarter of the usual dose of 6-mercaptopurine or azathioprine should be given;
Didanosine: plasma didanosine Cmax and AUC values were approximately doubled with concomitant allopurinol treatment; it should not be co-administered with allopurinol and if it must be, the dose of should be reduced and the person should be closely monitored.Allopurinol may also increase the activity or half-life of the following drugs, in order of seriousness and certainty of the interaction:
Ciclosporin
Coumarin anticoagulants, such as warfarin (reported rarely, but is serious when it occurs)
Vidarabine
Chlorpropamide
Phenytoin
Theophylline
Cyclophosphamide, doxorubicin, bleomycin, procarbazine, mechlorethamineCo-administration of the following drugs may make allopurinol less active or decrease its half-life:
Salicylates and medicines that increase the secretion of uric acid
furosemide (see more on diuretics below)Co-administration of the following drugs may cause hypersensitivity or skin rash:
Ampicillin and amoxicillin
Diuretics, in particular thiazides, especially in renal impairment
Angiotensin-converting-enzyme inhibitors (ACE inhibitors)
Pharmacology
A common misconception is that allopurinol is metabolized by its target, xanthine oxidase, but this action is principally carried out by aldehyde oxidase. The active metabolite of allopurinol is oxipurinol, which is also an inhibitor of xanthine oxidase. Allopurinol is almost completely metabolized to oxipurinol within two hours of oral administration, whereas oxipurinol is slowly excreted by the kidneys over 18–30 hours. For this reason, oxipurinol is believed responsible for the majority of allopurinols effect.
Mechanism of action
Allopurinol is a purine analog; it is a structural isomer of hypoxanthine (a naturally occurring purine in the body) and is an inhibitor of the enzyme xanthine oxidase. Xanthine oxidase is responsible for the successive oxidation of hypoxanthine and xanthine, resulting in the production of uric acid, the product of human purine metabolism. In addition to blocking uric acid production, inhibition of xanthine oxidase causes an increase in hypoxanthine and xanthine. While xanthine cannot be converted to purine ribotides, hypoxanthine can be salvaged to the purine ribotides adenosine and guanosine monophosphates. Increased levels of these ribotides may cause feedback inhibition of amidophosphoribosyl transferase, the first and rate-limiting enzyme of purine biosynthesis. Allopurinol, therefore, decreases uric acid formation and may also inhibit purine synthesis.
Pharmacogenetics
The HLA-B*5801 allele is a genetic marker for allopurinol-induced severe cutaneous adverse reactions, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). The frequency of the HLA-B*5801 allele varies between ethnicities: Han Chinese and Thai populations have HLA-B*5801 allele frequencies of around 8%, as compared to European and Japanese populations, who have allele frequencies of around 1.0% and 0.5%, respectively. The increase in risk for developing allopurinol-induced SJS or TEN in individuals with the HLA-B*5801 allele (as compared to those who do not have this allele) is very high, ranging from a 40-fold to a 580-fold increase in risk, depending on ethnicity. As of 2011 the FDA-approved drug label for allopurinol did not contain any information regarding the HLA-B*5801 allele, though FDA scientists did publish a study in 2011 which reported a strong, reproducible and consistent association between the allele and allopurinol-induced SJS and TEN. However, the American College of Rheumatology recommends screening for HLA-B*5801 in high-risk populations (e.g. Koreans with stage 3 or worse chronic kidney disease and those of Han Chinese and Thai descent), and prescribing patients who are positive for the allele an alternative drug. The Clinical Pharmacogenetics Implementation Consortium guidelines state that allopurinol is contraindicated in known carriers of the HLA-B*5801 allele.
History
Allopurinol was first synthesized and reported in 1956 by Roland K. Robins (1926-1992), in a search for antineoplastic agents. Because allopurinol inhibits the breakdown (catabolism) of the thiopurine drug mercaptopurine, and it was later tested by Wayne Rundles, in collaboration with Gertrude Elions lab at Wellcome Research Laboratories to see if it could improve treatment of acute lymphoblastic leukemia by enhancing the action of mercaptopurine. However, no improvement in leukemia response was noted with mercaptopurine-allopurinol co-therapy, so that work turned to other compounds and the team then started testing allopurinol as a potential therapeutic for gout. Allopurinol was first marketed as a treatment for gout in 1966.
Society and culture
Formulations
Allopurinol is sold as an injection for intravenous use and as a tablet.
Brands
Allopurinol has been marketed in the United States since 19 August 1966, when it was first approved by FDA under the trade name Zyloprim. Allopurinol was marketed at the time by Burroughs Wellcome. Allopurinol is a generic drug sold under a variety of brand names, including Allohexal, Allosig, Milurit, Alloril, Progout, Ürikoliz, Zyloprim, Zyloric, Zyrik, and Aluron.
See also
Lesinurad/allopurinol, a fixed-dose combination drug
Hydroxychavicol, potent xanthine oxidase inhibitor
References
Further reading
Dean L (March 2016). "Allopurinol Therapy and HLA-B*58:01 Genotype". In Pratt VM, McLeod HL, Rubinstein WS, et al. (eds.). Medical Genetics Summaries. National Center for Biotechnology Information (NCBI). PMID 28520356.
External links
"Allopurinol". Drug Information Portal. U.S. National Library of Medicine.
"PRODUCT INFORMATION Allopurinol Tablets USP". U.S. National Library of Medicine. Medication handout sheet (Revised: 07/2019 0603–2115)
Allopurinol pathway on PharmGKB |
Linaclotide | Linaclotide, (sold under the brand name Linzess in the US and Mexico, and as Constella elsewhere) is a drug used to treat irritable bowel syndrome with constipation and chronic constipation with no known cause.
It has a black box warning about the risk of serious dehydration in children in the US; the most common adverse effects in others are gastrointestinal.It is an oligo-peptide agonist of guanylate cyclase 2C and remains in the GI tract after it is taken orally. It was approved in the US and Europe in 2012.It is marketed by Allergan in most of the world and by Astellas in Asia; Ironwood Pharmaceuticals was the originator. In 2017, it was the 257th most commonly prescribed medication in the United States, with more than one million prescriptions.
Medical use
Linaclotide is used to treat irritable bowel syndrome with constipation and chronic constipation with no known cause.It has not been tested in pregnant women and it is unknown if it is excreted in breast milk.
Adverse effects
The US label has a black box warning to not use linaclotide in children less than 6 years old and to avoid in people from 6 to 18 years old, due to the risk of serious dehydration.More than 10% of people taking linaclotide have diarrhea. Between 1% and 10% of people have decreased appetite, dehydration, low potassium, dizziness when standing up too quickly, nausea, vomiting, urgent need to defecate, fecal incontinence, and bleeding in their colon, rectum, and anus.
Pharmacology
Systemic absorption of the globular tetradecapeptide is minimal.Linaclotide, like the endogenous guanylin and uroguanylin it mimics, is an agonist that activates the cell surface receptor of guanylate cyclase 2C (GC-C). The medication binds to the surface of the intestinal epithelial cells. Linaclotide is minimally absorbed and it is undetectable in the systemic circulation at therapeutic doses. Activation of GC-C increases cyclic guanosine monophosphate (cGMP). Elevated cGMP stimulates secretion of chloride and bicarbonate and water into the intestinal lumen, mainly by way of cystic fibrosis transmembrane conductance regulator (CFTR) ion channel activation. This results in increased intestinal fluid and accelerated transit. By elevating cGMP, linaclotide is also considered to reduce activation of colonic sensory neurons, reducing pain; and activates colonic motor neurons, which increases smooth muscle contraction and thus promotes bowel movements.
Chemistry
Linaclotide is a hybrid peptide design of the E.coli heat-stable enterotoxin (STa) and the endogenous peptide hormones endogenous guanylin and uroguanylin. It is a synthetic tetradecapeptide (14 amino acid peptide) with the sequence CCEYCCNPACTGCY by one-letter abbreviation, or by three-letter abbreviation:H–Cys1–Cys2–Glu3–Tyr4–Cys5–Cys6–Asn7–Pro8–Ala9–Cys10–Thr11–Gly12–Cys13–Tyr14–OH
However, the actual structure of linaclotide is not fully specified without the three disulfide (R-S-S-R) bonds it contains, which are between Cys1 and Cys6, between Cys2 and Cys10, and between Cys5 and Cys13; these are shown in exaggerated fashion in the line-angle graphic showing the chemical bonds within and between each amino acid (and their stereochemistries, see the infobox, above right), and are represented using a one-letter abbreviations in the following additional schematic:
A study in discovery synthesis reported that 2 of 14 strategies available to synthesize linaclotide were successful—the successful ones involving trityl protection of all cysteines, or trityl protection of all cysteines except Cys1 and Cys6, which were protected with tert-butylsulphenyl groups. The study also reported that solution-phase oxidation (disulfide formation) was advisable over solid-supported synthesis for linaclotide, and that the Cys1–Cys6 disulfide bridge was the most favored energetically.
History
The drug was discovered at Microbia, Inc, which had been spun out of the Whitehead Institute in 1998 by postdocs from the lab of Gerald Fink to commercialize the labs know-how and inventions related to microbial pathogens and biology. In 2002 the company hired Mark Currie who had worked at the Searle division of Monsanto and then had gone to Sepracor. Currie directed the efforts that led to the discovery of linaclotide, which was based on an enterotoxin produced by some strains of Escherichia coli that cause travelers diarrhea. The company started Phase I trials in 2004.Under a partnership agreement announced in 2007 between Forest Laboratories and Microbia, Forest would pay $70 million in licensing fees towards the development of linaclotide, with profits shared between the two companies in the US; Forest obtained exclusive rights to market in Canada and Mexico. By 2010, Microbia had changed its name to Ironwood Pharmaceuticals and had licensed rights to distribute the drug in Europe to Almirall and had licensed Asian rights to Astellas Pharma.It was approved in the US and Europe in 2012.Forest was acquired in 2014 and eventually became part of Allergan. Allergan acquired rights from Almirall in 2015 and in 2017 acquired remaining rights in most of the rest of the world, excluding North America, Japan, and China.In 2014, Ironwood and Forest then Allergan began running direct-to-consumer advertising which raised sales by 21%; campaigns in 2015 and 2016 raised sales by 27% and 30%.In January 2017, plecanatide, a drug marketed under the name Trulance, was approved by the FDA for the treatment of chronic idiopathic constipation (CIC), and is likewise an agonist of guanylate cyclase, except with hexadecapeptide structure.In 2017, the list price for linaclotide in the US was $378 for 30 pills and plecanatide was priced the same; Allergan and Ironwood increased the price of linaclotide to around $414 in 2018.In April 2022, the list price for linaclotide in the US was $501-$515 with discount for 30 capsules at the big chain pharmacies.
== References == |
Pentobarbital | Pentobarbital (previously known as pentobarbitone in Britain and Australia) is a short-acting barbiturate typically used as a sedative, a preanesthetic, and to control convulsions in emergencies. It can also be used for short-term treatment of insomnia but has been largely replaced by the benzodiazepine family of drugs.
In high doses, pentobarbital causes death by respiratory arrest. It is used for veterinary euthanasia and is used by some U.S. states and the U.S. federal government for executions of convicted criminals. In some countries and states, it is also used for physician-assisted suicide.Pentobarbital was widely abused and sometimes known as "yellow jackets" due to the yellow capsule of the Nembutal brand. Pentobarbital in oral (pill) form is no longer commercially available.
Uses
Medical
Typical applications for pentobarbital are sedative, short term hypnotic, preanesthetic, insomnia treatment, and control of convulsions in emergencies. Abbott Pharmaceutical discontinued manufacture of their Nembutal brand of Pentobarbital capsules in 1999, largely replaced by the benzodiazepine family of drugs. Pentobarbital was also widely abused, known on the street as "yellow jackets". They were available as 30, 50, and 100-milligram capsules of yellow, white-orange, and yellow colors, respectively.It is also used as a veterinary anesthetic agent.Pentobarbital can reduce intracranial pressure in Reyes syndrome, treat traumatic brain injury and induce coma in cerebral ischemia patients. Pentobarbital-induced coma has been advocated in patients with acute liver failure refractory to mannitol.
Euthanasia
Pentobarbital can cause death when used in high doses. It is used for euthanasia for humans as well as animals. It is taken alone, or in combination with complementary agents such as phenytoin, in commercial animal euthanasia injectable solutions.
In the Netherlands, it is part of the standard protocol for physician-assisted suicide for self-administration by the patient.It is taken by mouth for physician-assisted death in the United States states of Oregon, Washington, Vermont, and California (as of January, 2016).The oral dosage of pentobarbital indicated for physician-assisted suicide in Oregon is typically 10 g of liquid.In Switzerland, sodium pentobarbital is administered to the patient intravenously. Once administered, sleep is induced within 30 seconds, and the heart stops beating within 3 minutes.
Execution
Pentobarbital has been used or considered as a substitute for other drugs previously used for capital punishment in the United States when those drugs are unavailable. Such use however is illegal under Danish law, and when this was discovered, after public outcry in Danish media, Lundbeck, the owner of the drug, stopped selling it to US states that impose the death penalty. US distributors of the drug are forbidden by the owner to sell it to any customers, such as state authorities, that practice or participate in executions of humans.Texas began using pentobarbital for executing death-row inmates by lethal injection on July 18, 2012. The use of pentobarbital has been considered by several states, including Ohio, Arizona, Idaho, and Washington; those states made the decision to switch following shortages of pancuronium bromide, a muscle paralytic previously used as one component in a three-drug cocktail.In October 2013, Missouri changed its protocol to allow for compounded pentobarbital to be used in a lethal dose for executions. It was first used in November 2013.According to a December 2019 ProPublica article, by 2017 the Bureau of Prisons (BOP), in discussion with then Attorney General Jeff Sessions, had begun to search for suppliers of pentobarbital to be used in lethal injections. The BOP was aware that the use of pentobarbital as their "new drug choice" would be challenged in the courts because some lawyers had said that "pentobarbital would flood prisoners’ lungs with froth and foam, inflicting pain and terror akin to a death by drowning." BOP claimed that these concerns were unjustified and that their two expert witnesses asserted that the use of pentobarbital was "humane". On July 25, 2019, US Attorney General William Barr directed the federal government to resume capital punishment after 16 years. The drug of choice for these executions was pentobarbital.
Metabolism
Pentobarbital undergoes first-pass metabolism in the liver and possibly the intestines.
Drug interactions
Administration of ethanol, benzodiazepines, opioids, antihistamines, other sedative-hypnotics, and other central nervous system depressants will cause possible additive effects.
Chemistry
Pentobarbital is synthesized by methods analogous to that of amobarbital, the only difference being that the alkylation of α-ethylmalonic ester is carried out with 2-bromopentane in place of 1-bromo-3-methylbutane to give pentobarbital.
Society and culture
Names
Pentobarbital is the INN, AAN, BAN, and USAN while pentobarbitone is a former AAN and BAN.
One brand name for this drug is Nembutal, coined by John S. Lundy, who started using it in 1930, from the structural formula of the sodium salt—Na (sodium) + ethyl + methyl + butyl + al (common suffix for barbiturates). Nembutal is trademarked and manufactured by the Danish pharmaceutical company Lundbeck (now produced by Akorn Pharmaceuticals) and is the only injectable form of pentobarbital approved for sale in the United States. Abbott discontinued their Nembutal brand of Pentobarbital capsules in 1999, largely replaced by the Benzodiazepine family of drugs. Abbotts Nembutal, known on the streets as "yellow jackets", was widely abused. It was available in 50 and 100 mg strength yellow capsules.Pentobarbital can occur as a free acid, but is usually formulated as the sodium salt, pentobarbital sodium. The free acid is only slightly soluble in water and in ethanol.
See also
Animal euthanasia
List of veterinary drugs
References
External links
"Pentobarbital". Drug Information Portal. U.S. National Library of Medicine. |
Daratumumab/hyaluronidase | Daratumumab/hyaluronidase, sold under the brand name Darzalex Faspro, is a fixed-dose combination medication for the treatment of adults with newly diagnosed or relapsed/refractory multiple myeloma. It is a combination of daratumumab and hyaluronidase. It is administered via subcutaneous injection.The most common adverse reaction using daratumumab/hyaluronidase as monotherapy is upper respiratory tracts infection. The most common adverse reactions (≥20%) in people with amyloid light-chain amyloidosis who received daratumumab/hyaluronidase in combination with bortezomib, cyclophosphamide, and dexamethasone are upper respiratory tract infection, diarrhea, peripheral edema, constipation peripheral sensory neuropathy, fatigue, nausea, insomnia, dyspnea and cough. The most common adverse reactions (≥20%) occurring in people treated with daratumumab/hyaluronidase, carfilzomib, and dexamethasone were upper respiratory tract infections, fatigue, insomnia, hypertension, diarrhea, cough, dyspnea, headache, pyrexia, nausea, and edema peripheral.
Medical uses
Daratumumab/hyaluronidase is indicated for the treatment of adults with multiple myeloma:
in combination with bortezomib, melphalan and prednisone (D-VMP) in newly diagnosed adults who are ineligible for autologous stem cell transplant
in combination with lenalidomide and dexamethasone (D-Rd) in newly diagnosed adults who are ineligible for autologous stem cell transplant and in people with relapsed or refractory multiple myeloma who have received at least one prior therapy
in combination with bortezomib and dexamethasone (D-Vd) in adults who have received at least one prior therapy
as monotherapy, in adults who have received at least three prior lines of therapy including a proteasome inhibitor (PI) and an immunomodulatory agent or who are double-refractory to a PI and an immunomodulatory agent.In January 2021, the U.S. Food and Drug Administration (FDA) granted accelerated approval to daratumumab/hyaluronidase in combination with bortezomib, cyclophosphamide, and dexamethasone for newly diagnosed amyloid light-chain amyloidosis.In November 2021, the FDA granted approval to daratumumab/hyaluronidase in combination with carfilzomib plus dexamethasone to treat relapsed or refractory multiple myeloma in adults who have received one to three prior lines of therapy.
History
It was approved for use in the United States in May 2020.Efficacy of daratumumab and hyaluronidase-fihji (monotherapy) was evaluated in the COLUMBA trial (NCT03277105), an open-label non-inferiority trial randomizing 263 participants to daratumumab and hyaluronidase-fihj and 259 to intravenous daratumumab (daratumumab IV). The trials co-primary endpoints were overall response rate (ORR) and pharmacokinetic (PK) endpoint of the maximum Ctrough on cycle 3, day 1 pre-dose. Daratumumab and hyaluronidase-fihj was non-inferior to daratumumab IV in evaluating these two endpoints.Efficacy of daratumumab and hyaluronidase-fihj in combination with VMP (D-VMP) was evaluated in a single-arm cohort of the PLEIADES trial (NCT03412565), a multi-cohort, open‑label trial. Eligible participants were required to have newly diagnosed multiple myeloma and were ineligible for transplant.Efficacy of daratumumab and hyaluronidase-fihj in combination with Rd (D-Rd) was evaluated in a single-arm cohort of this trial. Eligible participants had received at least one prior line of therapy.
Efficacy of daratumumab/hyaluronidase in combination with bortezomib, cyclophosphamide, and dexamethasone was evaluated in ANDROMEDA (NCT03201965), an open-label, randomized, active-controlled trial in 388 participants with newly diagnosed amyloid light-chain amyloidosis with measurable disease and at least one affected organ according to consensus criteria. Participants were randomized to receive bortezomib, cyclophosphamide, and dexamethasone (VCd arm) or with daratumumab and hyaluronidase (D-VCd arm).Efficacy of daratumumab/hyaluronidase in combination with carfilzomib and dexamethasone was evaluated in PLEIADES (NCT03412565), a multi-cohort, open-label trial.
References
External links
"Daratumumab". Drug Information Portal. U.S. National Library of Medicine.
"Hyaluronidase (Human recombinant)". Drug Information Portal. U.S. National Library of Medicine.
Clinical trial number NCT03277105 for "A Study of Subcutaneous Versus (vs.) Intravenous Administration of Daratumumab in Participants With Relapsed or Refractory Multiple Myeloma" at ClinicalTrials.gov
Clinical trial number NCT03412565 for "A Study to Evaluate Subcutaneous Daratumumab in Combination With Standard Multiple Myeloma Treatment Regimens" at ClinicalTrials.gov
Clinical trial number NCT03201965 for "A Study to Evaluate the Efficacy and Safety of Daratumumab in Combination With Cyclophosphamide, Bortezomib and Dexamethasone (CyBorD) Compared to CyBorD Alone in Newly Diagnosed Systemic Amyloid Light-chain (AL) Amyloidosis" at ClinicalTrials.gov |
Metformin | Metformin, sold under the brand name Glucophage, among others, is the main first-line medication for the treatment of type 2 diabetes, particularly in people who are overweight. It is also used in the treatment of polycystic ovary syndrome. It is not associated with weight gain and is taken by mouth. It is sometimes used as an off-label adjunct to lessen the risk of metabolic syndrome in people who take antipsychotics.Metformin is generally well tolerated. Common adverse effects include diarrhea, nausea, and abdominal pain. It has a small risk of causing low blood sugar. High blood lactic acid level is a concern if the medication is used in overly large doses or prescribed in people with severe kidney problems. It is not recommended in those with significant liver disease.
Metformin is a biguanide antihyperglycemic agent. It works by decreasing glucose production in the liver, by increasing the insulin sensitivity of body tissues, and by increasing GDF15 secretion, which reduces appetite and caloric intake.Metformin was discovered in 1922. French physician Jean Sterne began the study in humans in the 1950s. It was introduced as a medication in France in 1957 and the United States in 1995. It is on the World Health Organizations List of Essential Medicines. Metformin is the most widely used medication for diabetes taken by mouth. It is available as a generic medication. In 2020, it was the third most-commonly prescribed medication in the United States, with more than 92 million prescriptions.
Medical uses
Metformin is used to lower the blood sugar in those with type 2 diabetes. It is also used as a second-line agent for infertility in those with polycystic ovary syndrome.
Type 2 diabetes
The American Diabetes Association and the American College of Physicians both recommend metformin as a first-line agent to treat type 2 diabetes. It is as effective as repaglinide and more effective than all other oral diabetes mellitus type 2 drugs.
Efficacy
Treatment guidelines for major professional associations, including the European Association for the Study of Diabetes, the European Society for Cardiology, and the American Diabetes Association, describe evidence for the cardiovascular benefits of metformin as equivocal. A 2020 Cochrane systematic review did not find enough evidence of reduction of cardiovascular mortality, non-fatal myocardial infarction or non-fatal stroke when comparing metformin monotherapy to other glucose-lowering drugs, behaviour change interventions, placebo or no intervention.The use of metformin reduces body weight in people with type 2 diabetes mellitus in contrast to sulfonylureas, which are associated with weight gain. Some evidence shows that metformin is associated with weight loss in obesity in the absence of diabetes. Metformin has a lower risk of hypoglycemia than the sulfonylureas, although hypoglycemia has uncommonly occurred during intense exercise, calorie deficit, or when used with other agents to lower blood glucose. Metformin modestly reduces low density lipoprotein and triglyceride levels.
Polycystic ovarian syndrome
In those with polycystic ovarian syndrome (PCOS), tentative evidence shows that metformin use increases the rate of live births. This includes in those who have not been able to get pregnant with clomiphene. Metformin does not appear to change the risk of miscarriage. A number of other benefits have also been found both during pregnancy and in nonpregnant women with PCOS. In an updated Cochrane (2020) review on metformin versus placebo/no treatment before or during IVF/ICSI in women with PCOS no conclusive evidence of improved live birth rates was found. In long GnRH-agonist protocols there was uncertainty in the evidence of improved live birth rates but there could be increases in clinical pregnancy rate. In short GnRH-antagonist protocols metformin may reduce live birth rates with uncertainty on its effect on clinical pregnancy rate. Metformin may result in a reduction of OHSS but could come with a greater frequency of side effects. There was uncertainty as to metformins impact on miscarriage. The evidence does not support general use during pregnancy for improving maternal and infant outcomes in obese women.The United Kingdoms National Institute for Health and Clinical Excellence recommended in 2004 that women with PCOS and a body mass index above 25 be given metformin for anovulation and infertility when other therapies fail to produce results. UK and international clinical practice guidelines do not recommend metformin as a first-line treatment or do not recommend it at all, except for women with glucose intolerance. The guidelines suggest clomiphene as the first medication option and emphasize lifestyle modification independently from medical treatment. Metformin treatment decreases the risk of developing type 2 diabetes mellitus in women with PCOS who exhibited impaired glucose tolerance at baseline.
Diabetes mellitus and pregnancy
A total review of metformin use during pregnancy compared to insulin alone found good short-term safety for both the mother and baby, but unclear long-term safety. Several observational studies and randomized controlled trials found metformin to be as effective and safe as insulin for the management of gestational diabetes. Nonetheless, several concerns have been raised and evidence on the long-term safety of metformin for both mother and child is lacking. Compared with insulin, women with gestational diabetes treated with metformin gain less weight and are less likely to develop pre‐eclampsia during pregnancy. Babies born to women treated with metformin have less visceral fat, and this may make them less prone to insulin resistance in later life. The use of metformin for gestational diabetes resulted in smaller babies compared to treatment with insulin. However, despite initially lower birth weight, children exposed to metformin during pregnancy had accelerated growth after birth, and were heavier by mid-childhood than those exposed to insulin during pregnancy. This pattern of initial low birth weight followed by catch-up growth that surpasses comparative children has been associated with long-term cardiometabolic disease.
Weight change
Metformin use is typically associated with weight loss. It appears to be safe and effective in counteracting the weight gain caused by the antipsychotic medications olanzapine and clozapine. Although modest reversal of clozapine-associated weight gain is found with metformin, primary prevention of weight gain is more valuable.
Use with insulin
Metformin may reduce the insulin requirement in type 1 diabetes, albeit with an increased risk of hypoglycemia.
Life extension
There is some evidence metformin may be helpful in extending lifespan, even in otherwise healthy people. It has received substantial interest as an agent that delays aging, possibly through similar mechanisms as its treatment of diabetes (insulin and carbohydrate regulation). This is controversial, and an area of active research.
Alzheimers disease
The possibility that metformin can delay the onset or progression of Alzheimers, or even prevent it, is under investigation. There has been a variety of research published in this field in an effort to establish a correlation between type 2 diabetes and Alzheimers disease. Research now includes studies with participants not diagnosed with diabetes.
Contraindications
Metformin is contraindicated in people with:
Severe renal impairment (estimated glomerular filtration rate (eGFR) below 30 mL/min/1.73 m2)
Known hypersensitivity to metformin
Acute or chronic metabolic acidosis, including diabetic ketoacidosis (from uncontrolled diabetes), with or without comaWarnings are also given regarding the use of metformin in less severe renal impairment, people aged 65 years old or greater, hypoxic states (e.g., acute congestive heart failure), excessive alcohol intake, hepatic impairment, concomitant use of certain drugs (e.g. carbonic anhydrase inhibitors such as topiramate), surgery, and other procedures, or in people having a radiological study with administration of an iodinated contrast agent.Metformin is recommended to be temporarily discontinued before any procedure involving use of iodinated contrast agents, (such as a contrast-enhanced CT scan or angiogram) due to the increased risk of lactic acidosis resulting from impaired kidney function; metformin can be resumed after two days after contrast administration, if renal function is adequate and stable.
Adverse effects
The most common adverse effect of metformin is gastrointestinal irritation, including diarrhea, cramps, nausea, vomiting, and increased flatulence; metformin is more commonly associated with gastrointestinal adverse effects than most other antidiabetic medications. The most serious potential adverse effect of metformin is lactic acidosis; this complication is rare, and the vast majority of these cases seem to be related to conditions such as impaired liver or kidney function, rather than to the metformin itself. Metformin is not approved for use in those with severe kidney disease, but may still be used at lower doses in those with kidney problems.
Gastrointestinal
Gastrointestinal upset can cause severe discomfort; it is most common when metformin is first administered, or when the dose is increased. The discomfort can often be avoided by beginning at a low dose (1.0 to 1.7 g/day) and increasing the dose gradually, but even with low doses, 5% of people may be unable to tolerate metformin. Use of slow or extended-release preparations may improve tolerability.Long-term use of metformin has been associated with increased homocysteine levels and malabsorption of vitamin B12. Higher doses and prolonged use are associated with increased incidence of vitamin B12 deficiency, and some researchers recommend screening or prevention strategies.
Lactic acidosis
Lactic acidosis almost never occurs with metformin exposure during routine medical care. Rates of metformin-associated lactic acidosis are about nine per 100,000 persons/year, which is similar to the background rate of lactic acidosis in the general population. A systematic review concluded no data exists to definitively link metformin to lactic acidosis.Metformin is generally safe in people with mild to moderate chronic kidney disease, with proportional reduction of metformin dose according to severity of estimated glomerular filtration rate (eGFR) and with periodic assessment of kidney function, (e.g., periodic plasma creatinine measurement). The FDA recommends avoiding the use of metformin in more severe chronic kidney disease, below the eGFR cutoff of 30 mL/minute/1.73 m2. Lactate uptake by the liver is diminished with metformin use because lactate is a substrate for hepatic gluconeogenesis, a process that metformin inhibits. In healthy individuals, this slight excess is cleared by other mechanisms (including uptake by unimpaired kidneys), and no significant elevation in blood levels of lactate occurs. Given severely impaired kidney function, clearance of metformin and lactate is reduced, increasing levels of both, and possibly causing lactic acid buildup. Because metformin decreases liver uptake of lactate, any condition that may precipitate lactic acidosis is a contraindication. Common causes include alcoholism (due to depletion of NAD+ stores), heart failure, and respiratory disease (due to inadequate tissue oxygenation); the most common cause is kidney disease.Metformin-associated lactate production may also take place in the large intestine, which could potentially contribute to lactic acidosis in those with risk factors. The clinical significance of this is unknown, though, and the risk of metformin-associated lactic acidosis is most commonly attributed to decreased hepatic uptake rather than increased intestinal production.The risk of metformin-associated lactic acidosis is also increased by a massive overdose of metformin, although even quite large doses are often not fatal.
Overdose
The most common symptoms following an overdose include vomiting, diarrhea, abdominal pain, tachycardia, drowsiness, and rarely, hypoglycemia or hyperglycemia. Treatment of metformin overdose is generally supportive, as no specific antidote is known. Extracorporeal treatments are recommended in severe overdoses. Due to metformins low molecular weight and lack of plasma protein binding, these techniques have the benefit of removing metformin from the blood plasma, preventing further lactate overproduction.Metformin may be quantified in blood, plasma, or serum to monitor therapy, confirm a diagnosis of poisoning, or to assist in a forensic death investigation. Blood or plasma metformin concentrations are usually in a range of 1–4 mg/L in persons receiving therapeutic doses, 40–120 mg/L in victims of acute overdosage, and 80–200 mg/L in fatalities. Chromatographic techniques are commonly employed.
Interactions
The H2-receptor antagonist cimetidine causes an increase in the plasma concentration of metformin by reducing clearance of metformin by the kidneys; both metformin and cimetidine are cleared from the body by tubular secretion, and both, particularly the cationic (positively charged) form of cimetidine, may compete for the same transport mechanism. A small double-blind, randomized study found the antibiotic cephalexin to also increase metformin concentrations by a similar mechanism; theoretically, other cationic medications may produce the same effect.Metformin also interacts with anticholinergic medications, due to their effect on gastric motility. Anticholinergic drugs reduce gastric motility, prolonging the time drugs spend in the gastrointestinal tract. This impairment may lead to more metformin being absorbed than without the presence of an anticholinergic drug, thereby increasing the concentration of metformin in the plasma and increasing the risk for adverse effects.
Pharmacology
Mechanism of action
The molecular mechanism of metformin is not completely understood. Multiple potential mechanisms of action have been proposed: inhibition of the mitochondrial respiratory chain (complex I), activation of AMP-activated protein kinase (AMPK), inhibition of glucagon-induced elevation of cyclic adenosine monophosphate (cAMP) with reduced activation of protein kinase A (PKA), complex IV–mediated inhibition of the GPD2 variant of mitochondrial glycerol-3-phosphate dehydrogenase (thereby reducing glycerol-derived hepatic gluconeogenesis), and an effect on gut microbiota. Metformin also exerts an anorexiant effect in most people, decreasing caloric intake. Metformin decreases gluconeogenesis (glucose production) in the liver. Metformin inhibits basal secretion from the pituitary gland of growth hormone, adrenocorticotropic hormone, follicle stimulating hormone, and expression of proopiomelanocortin, which in part accounts for its insulin-sensitizing effect with multiple actions on tissues including the liver, skeletal muscle, endothelium, adipose tissue, and the ovaries. The average patient with type 2 diabetes has three times the normal rate of gluconeogenesis; metformin treatment reduces this by over one-third.Activation of AMPK was required for metformins inhibitory effect on liver glucose production. AMPK is an enzyme that plays an important role in insulin signalling, whole-body energy balance, and the metabolism of glucose and fats. AMPK activation was required for an increase in the expression of small heterodimer partner, which in turn inhibited the expression of the hepatic gluconeogenic genes phosphoenolpyruvate carboxykinase and glucose 6-phosphatase. Metformin is frequently used in research along with AICA ribonucleotide as an AMPK agonist. The mechanism by which biguanides increase the activity of AMPK remains uncertain: metformin increases the concentration of cytosolic adenosine monophosphate (AMP) (as opposed to a change in total AMP or total AMP/adenosine triphosphate) which could activate AMPK allosterically at high levels; a newer theory involves binding to PEN-2. Metformin inhibits cyclic AMP production, blocking the action of glucagon, and thereby reducing fasting glucose levels. Metformin also induces a profound shift in the faecal microbial community profile in diabetic mice, and this may contribute to its mode of action possibly through an effect on glucagon-like peptide-1 secretion.In addition to suppressing hepatic glucose production, metformin increases insulin sensitivity, enhances peripheral glucose uptake (by inducing the phosphorylation of GLUT4 enhancer factor), decreases insulin-induced suppression of fatty acid oxidation, and decreases the absorption of glucose from the gastrointestinal tract. Increased peripheral use of glucose may be due to improved insulin binding to insulin receptors. The increase in insulin binding after metformin treatment has also been demonstrated in patients with diabetes mellitus type 2.AMPK probably also plays a role in increased peripheral insulin sensitivity, as metformin administration increases AMPK activity in skeletal muscle. AMPK is known to cause GLUT4 deployment to the plasma membrane, resulting in insulin-independent glucose uptake. Some metabolic actions of metformin do appear to occur by AMPK-independent mechanisms.
Metformin has indirect antiandrogenic effects in women with insulin resistance, such as those with PCOS, due to its beneficial effects on insulin sensitivity. It may reduce testosterone levels in such women by as much as 50%. A Cochrane review, though, found that metformin was only slightly effective for decreasing androgen levels in women with PCOS.Metformin also has significant effects on the gut microbiome, such as its effect on increasing agmatine production by gut bacteria, but the relative importance of this mechanism compared to other mechanisms is uncertain.
Pharmacokinetics
Metformin has an oral bioavailability of 50–60% under fasting conditions, and is absorbed slowly. Peak plasma concentrations (Cmax) are reached within 1–3 hours of taking immediate-release metformin and 4–8 hours with extended-release formulations. The plasma protein binding of metformin is negligible, as reflected by its very high apparent volume of distribution (300–1000 L after a single dose). Steady state is usually reached in 1–2 days.Metformin has acid dissociation constant values (pKa) of 2.8 and 11.5, so it exists very largely as the hydrophilic cationic species at physiological pH values. The metformin pKa values make it a stronger base than most other basic medications with less than 0.01% nonionized in blood. Furthermore, the lipid solubility of the nonionized species is slight as shown by its low logP value (log(10) of the distribution coefficient of the nonionized form between octanol and water) of −1.43. These chemical parameters indicate low lipophilicity and, consequently, rapid passive diffusion of metformin through cell membranes is unlikely. As a result of its low lipid solubility it requires the transporter SLC22A1 in order for it to enter cells. The logP of metformin is less than that of phenformin (−0.84) because two methyl substituents on metformin impart lesser lipophilicity than the larger phenylethyl side chain in phenformin. More lipophilic derivatives of metformin are presently under investigation with the aim of producing prodrugs with superior oral absorption than metformin.Metformin is not metabolized. It is cleared from the body by tubular secretion and excreted unchanged in the urine; it is undetectable in blood plasma within 24 hours of a single oral dose. The average elimination half-life in plasma is 6.2 hours. Metformin is distributed to (and appears to accumulate in) red blood cells, with a much longer elimination half-life: 17.6 hours (reported as ranging from 18.5 to 31.5 hours in a single-dose study of nondiabetics).Some evidence indicates that liver concentrations of metformin in humans may be two to three times higher than plasma concentrations, due to portal vein absorption and first-pass uptake by the liver in oral administration.
Chemistry
Metformin hydrochloride (1,1-dimethylbiguanide hydrochloride) is freely soluble in water, slightly soluble in ethanol, but almost insoluble in acetone, ether, or chloroform. The pKa of metformin is 12.4. The usual synthesis of metformin, originally described in 1922, involves the one-pot reaction of dimethylamine hydrochloride and 2-cyanoguanidine over heat.
According to the procedure described in the 1975 Aron patent, and the Pharmaceutical Manufacturing Encyclopedia, equimolar amounts of dimethylamine and 2-cyanoguanidine are dissolved in toluene with cooling to make a concentrated solution, and an equimolar amount of hydrogen chloride is slowly added. The mixture begins to boil on its own, and after cooling, metformin hydrochloride precipitates with a 96% yield.
Derivatives
A new derivative HL156A, also known as IM156, is potential new drug for medical use.
History
The biguanide class of antidiabetic medications, which also includes the withdrawn agents phenformin and buformin, originates from the French lilac or goats rue (Galega officinalis), a plant used in folk medicine for several centuries. G. officinalis itself does not contain any of these medications, but isoamylene guanidine; phenformin, buformin, and metformin are chemically synthesized compounds composed of two guanidine molecules, and are more lipophilic than the plant-derived parent compound.Metformin was first described in the scientific literature in 1922, by Emil Werner and James Bell, as a product in the synthesis of N,N-dimethylguanidine. In 1929, Slotta and Tschesche discovered its sugar-lowering action in rabbits, finding it the most potent biguanide analog they studied. This result was completely forgotten, as other guanidine analogs such as the synthalins, took over and were themselves soon overshadowed by insulin.Interest in metformin resumed at the end of the 1940s. In 1950, metformin, unlike some other similar compounds, was found not to decrease blood pressure and heart rate in animals. That year, Filipino physician Eusebio Y. Garcia used metformin (he named it Fluamine) to treat influenza; he noted the medication "lowered the blood sugar to minimum physiological limit" and was not toxic. Garcia believed metformin to have bacteriostatic, antiviral, antimalarial, antipyretic, and analgesic actions. In a series of articles in 1954, Polish pharmacologist Janusz Supniewski was unable to confirm most of these effects, including lowered blood sugar. Instead he observed antiviral effects in humans.French diabetologist Jean Sterne studied the antihyperglycemic properties of galegine, an alkaloid isolated from G. officinalis, which is related in structure to metformin, and had seen brief use as an antidiabetic before the synthalins were developed. Later, working at Laboratoires Aron in Paris, he was prompted by Garcias report to reinvestigate the blood sugar-lowering activity of metformin and several biguanide analogs. Sterne was the first to try metformin on humans for the treatment of diabetes; he coined the name "Glucophage" (glucose eater) for the medication and published his results in 1957.Metformin became available in the British National Formulary in 1958. It was sold in the UK by a small Aron subsidiary called Rona.Broad interest in metformin was not rekindled until the withdrawal of the other biguanides in the 1970s. Metformin was approved in Canada in 1972, but did not receive approval by the U.S. Food and Drug Administration (FDA) for type 2 diabetes until 1994. Produced under license by Bristol-Myers Squibb, Glucophage was the first branded formulation of metformin to be marketed in the U.S., beginning on 3 March 1995. Generic formulations are now available in several countries, and metformin is believed to have become the worlds most widely prescribed antidiabetic medication.
Society and culture
Environmental
Metformin and its major transformation product guanylurea are present in wastewater treatment plant effluents and regularly detected in surface waters. Guanylurea concentrations above 200 μg/L have been measured in a German river, which are amongst the highest reported for pharmaceutical transformation products in aquatic environments.
Formulations
The name "Metformin" is the BAN, USAN, and INN for this medication, and is sold under several trade names. Common brand names include Glucophage, Riomet, Fortamet, and Glumetza in the US. In other areas of the world, there is also Obimet, Gluformin, Dianben, Diabex, Diaformin, Metsol, Siofor, Metfogamma and Glifor. There are several formulations of Metformin available to the market, and all but the liquid form have generic equivalents. Metformin IR (immediate release) is available in 500-, 850-, and 1000-mg tablets, while Metformin XR (extended release) is available in 500-, 750-, and 1000-mg strengths (also sold as Fortamet, Glumetza, and Glucophage XR in the US). The use of an extended release formulation is to counteract common gastrointestinal adverse effects, as well as to increase compliance by reducing pill burden and therefore can improve adherence, at the expense of the pills larger size. Also available is liquid metformin (sold only as Riomet in the US), where 5 mL of solution contains the same amount of drug as a 500-mg tablet. The use of a liquid form can be beneficial in helping those with physical or psychological swallowing problems take the medication, or to potentially reduce the number of steps needed to take the medication.
Combination with other medications
When used for type 2 diabetes, metformin is often prescribed in combination with other medications.
Several are available as fixed-dose combinations, with the potential to reduce pill burden, decrease cost, and simplify administration.
Thiazolidinediones (glitazones)
Rosiglitazone
A combination of metformin and rosiglitazone was released in 2002, and sold as Avandamet by GlaxoSmithKline, or as a generic medication. Formulations are 500/1, 500/2, 500/4, 1000/2, and 1000 mg/4 mg of metformin/rosiglitazone.
By 2009, it had become the most popular metformin combination.In 2005, the stock of Avandamet was removed from the market, after inspections showed the factory where it was produced was violating good manufacturing practices. The medication pair continued to be prescribed separately, and Avandamet was again available by the end of that year. A generic formulation of metformin/rosiglitazone from Teva received tentative approval from the FDA and reached the market in early 2012.However, following a meta-analysis in 2007 that linked the medications use to an increased risk of heart attack, concerns were raised over the safety of medicines containing rosiglitazone. In September 2010, the European Medicines Agency recommended that the medication be suspended from the European market because the benefits of rosiglitazone no longer outweighed the risks.It was withdrawn from the market in the UK and India in 2010, and in New Zealand and South Africa in 2011. From November 2011 until November 2013 the FDA did not allow rosiglitazone or metformin/rosiglitazone to be sold without a prescription; moreover, makers were required to notify patients of the risks associated with its use, and the drug had to be purchased by mail order through specified pharmacies.In November 2013, the FDA lifted its earlier restrictions on rosiglitazone after reviewing the results of the 2009 RECORD clinical trial (a six-year, open-label randomized control trial), which failed to show elevated risk of heart attack or death associated with the medication.
Pioglitazone
The combination of metformin and pioglitazone (Actoplus Met, Piomet, Politor, Glubrava) is available in the US and the European Union.
DPP-4 inhibitors
Dipeptidyl peptidase |
Metformin | -4 inhibitors inhibit dipeptidyl peptidase-4 and thus reduce glucagon and blood glucose levels.
DPP-4 inhibitors combined with metformin include a sitagliptin/metformin combination (Janumet), a saxagliptin/metformin combination (Kombiglyze XR, Komboglyze), and an alogliptin/metformin combination (Kazano, Vipdomet).Linagliptin combined with metformin hydrochloride is sold under the brand name Jentadueto. As of August 2021, linagliptin/metformin is available as a generic medicine in the US.SGLT-2 inhibitors
There are combinations of metformin with dapagliflozin, empgaliflozin and canagliflzoin.
Sulfonylureas
Sulfonylureas act by increasing insulin release from the beta cells in the pancreas. They often can be used as secondary therapy if metformin alone is not sufficiently effective at reaching normal blood glucose levels.
Metformin is available combined with the sulfonylureas glipizide (Metaglip) and glibenclamide (US: glyburide) (Glucovance). Generic formulations of metformin/glipizide and metformin/glibenclamide are available (the latter is more popular).
Meglitinide
Meglitinides are similar to sulfonylureas, as they bind to beta cells in the pancreas, but differ by the site of binding to the intended receptor and the drugs affinities to the receptor. As a result, they have a shorter duration of action compared to sulfonylureas, and require higher blood glucose levels to begin to secrete insulin. Both meglitinides, known as nateglinide and repanglinide, is sold in formulations combined with metformin. A repaglinide/metformin combination is sold as Prandimet, or as its generic equivalent.
Triple combination
The combination of metformin with dapagliflozen and saxagliptin is available in the United States as Qternmet XR.The combination of metformin with pioglitazone and glibenclamide is available in India as Accuglim-MP, Adglim MP, and Alnamet-GP, along with the Philippines as Tri-Senza.The combination of metformin with pioglitazone and lipoic acid is available in Turkey as Pional.
Impurities
In December 2019, the U.S. FDA announced that it learned that some metformin medicines manufactured outside the United States might contain a nitrosamine impurity called N-nitrosodimethylamine (NDMA), classified as a probable human carcinogen, at low levels. Health Canada announced that it was assessing NDMA levels in metformin.In February 2020, the FDA found NDMA levels in some tested metformin samples that did not exceed the acceptable daily intake.In February 2020, Health Canada announced a recall of Apotex immediate-release metformin, followed in March by recalls of Ranbaxy metformin and in March by Jamp metformin.On 29 May 2020, the FDA asked five companies to voluntarily recall their sustained-release metformin products. The five companies were not named, but they were revealed to be Amneal Pharmaceuticals, Actavis Pharma, Apotex Corp, Lupin Pharma, and Marksans Pharma Limited in a letter sent to Valisure, the pharmacy that had first alerted the FDA to this contaminant in metformin via a Citizen Petition.In June 2020, the FDA posted its laboratory results showing NDMA amounts in metformin products it tested. It found NDMA in certain lots of ER metformin, and is recommending companies recall lots with levels of NDMA above the acceptable intake limit of 96 nanograms per day. The FDA is also collaborating with international regulators to share testing results for metformin.In July 2020, Lupin Pharmaceuticals pulled all lots (batches) of metformin after discovering unacceptably high levels of NDMA in tested samples.In August 2020, Bayshore Pharmaceuticals recalled two lots of tablets.
Research
Metformin has been studied for its effects on multiple other conditions, including:
Non-alcoholic fatty liver disease
Premature puberty
Cancer
Cardiovascular disease in people with diabetes
AgingWhile metformin may reduce body weight in persons with fragile X syndrome, whether it improves neurological or psychiatric symptoms is uncertain. Metformin has been studied in vivo (C. elegans and crickets) for effects on aging. A 2017 review found that people with diabetes who were taking metformin had lower all-cause mortality. They also had reduced cancer and cardiovascular disease compared with those on other therapies.
References
Further reading
External links
"Metformin". Drug Information Portal. U.S. National Library of Medicine.
"Metformin hydrochloride". Drug Information Portal. U.S. National Library of Medicine. |
Mannitol | Mannitol is a type of sugar alcohol used as a sweetener and medication. It is used as a low calorie sweetener as it is poorly absorbed by the intestines. As a medication, it is used to decrease pressure in the eyes, as in glaucoma, and to lower increased intracranial pressure. Medically, it is given by injection or inhalation. Effects typically begin within 15 minutes and last up to 8 hours.Common side effects from medical use include electrolyte problems and dehydration. Other serious side effects may include worsening heart failure and kidney problems. It is unclear if use is safe in pregnancy. Mannitol is in the osmotic diuretic family of medications and works by pulling fluid from the brain and eyes.The discovery of mannitol is attributed to Joseph Louis Proust in 1806. It is on the World Health Organizations List of Essential Medicines. It was originally made from the flowering ash and called manna due to its supposed resemblance to the Biblical food. Mannitol is on the World Anti-Doping Agencys banned drug list due to concerns that it may mask other drugs.
Uses
Medical uses
In the United States, mannitol is indicated for the reduction of intracranial pressure and treatment of cerebral edema and elevated intraocular pressure.In the European Union, mannitol is indicated for the treatment of cystic fibrosis (CF) in adults aged 18 years and above as an add-on therapy to best standard of care.Mannitol is used intravenously to reduce acutely raised intracranial pressure until more definitive treatment can be applied, e.g., after head trauma. While mannitol injection is the mainstay for treating high pressure in the skull after a bad brain injury, it is no better than hypertonic saline as a first-line treatment. In treatment-resistant cases, hypertonic saline works better. Intra-arterial infusions of mannitol can transiently open the blood-brain barrier by disrupting tight junctions.It may also be used for certain cases of kidney failure with low urine output, decreasing pressure in the eye, to increase the elimination of certain toxins, and to treat fluid build up.Intraoperative mannitol prior to vessel clamp release during renal transplant has been shown to reduce post-transplant kidney injury, but has not been shown to reduce graft rejection.Mannitol acts as an osmotic laxative in oral doses larger than 20 g, and is sometimes sold as a laxative for children.The use of mannitol, when inhaled, as a bronchial irritant as an alternative method of diagnosis of exercise-induced asthma has been proposed. A 2013 systematic review concluded evidence to support its use for this purpose at this time is insufficient.Mannitol is commonly used in the circuit prime of a heart lung machine during cardiopulmonary bypass. The presence of mannitol preserves renal function during the times of low blood flow and pressure, while the patient is on bypass. The solution prevents the swelling of endothelial cells in the kidney, which may have otherwise reduced blood flow to this area and resulted in cell damage.
Mannitol can also be used to temporarily encapsulate a sharp object (such as a helix on a lead for an artificial pacemaker) while it passes through the venous system. Because the mannitol dissolves readily in blood, the sharp point becomes exposed at its destination.
Mannitol is also the first drug of choice to treat acute glaucoma in veterinary medicine. It is administered as a 20% solution intravenously. It dehydrates the vitreous humor and, therefore, lowers the intraocular pressure. However, it requires an intact blood-ocular barrier to work.
Food
Mannitol increases blood glucose to a lesser extent than sucrose (thus having a relatively low glycemic index) so is used as a sweetener for people with diabetes, and in chewing gums. Although mannitol has a higher heat of solution than most sugar alcohols, its comparatively low solubility reduces the cooling effect usually found in mint candies and gums. However, when mannitol is completely dissolved in a product, it induces a strong cooling effect. Also, it has a very low hygroscopicity – it does not pick up water from the air until the humidity level is 98%. This makes mannitol very useful as a coating for hard candies, dried fruits, and chewing gums, and it is often included as an ingredient in candies and chewing gum. The pleasant taste and mouthfeel of mannitol also makes it a popular excipient for chewable tablets.
Analytical chemistry
Mannitol can be used to form a complex with boric acid. This increases the acid strength of the boric acid, permitting better precision in volumetric analysis of this acid.
Other
Mannitol is the primary ingredient of mannitol salt agar, a bacterial growth medium, and is used in others.
Mannitol is used as a cutting agent in various drugs that are used intranasally (snorted), such as cocaine. A mixture of mannitol and fentanyl (or fentanyl analogs) in ratio 1:10 is labeled and sold as "China white", a popular heroin substitute.
Contraindications
Mannitol is contraindicated in people with anuria, severe hypovolemia, pre-existing severe pulmonary vascular congestion or pulmonary edema, irritable bowel syndrome (IBS), and active intracranial bleeding except during craniotomy.Adverse effects include hyponatremia and volume depletion leading to metabolic acidosis.
Chemistry
Mannitol is an isomer of sorbitol, another sugar alcohol; the two differ only in the orientation of the hydroxyl group on carbon 2. While similar, the two sugar alcohols have very different sources in nature, melting points, and uses.
Production
Mannitol is classified as a sugar alcohol; that is, it can be derived from a sugar (mannose) by reduction. Other sugar alcohols include xylitol and sorbitol. Mannitol and sorbitol are isomers, the only difference being the orientation of the hydroxyl group on carbon 2.
Industrial synthesis
Mannitol is commonly produced via the hydrogenation of fructose, which is formed from either starch or sucrose (common table sugar). Although starch is a cheaper source than sucrose, the transformation of starch is much more complicated. Eventually, it yields a syrup containing about 42% fructose, 52% glucose, and 6% maltose. Sucrose is simply hydrolyzed into an invert sugar syrup, which contains about 50% fructose. In both cases, the syrups are chromatographically purified to contain 90–95% fructose. The fructose is then hydrogenated over a nickel catalyst into a mixture of isomers sorbitol and mannitol. Yield is typically 50%:50%, although slightly alkaline reaction conditions can slightly increase mannitol yields.
Biosyntheses
Mannitol is one of the most abundant energy and carbon storage molecules in nature, produced by a plethora of organisms, including bacteria, yeasts, fungi, algae, lichens, and many plants. Fermentation by microorganisms is an alternative to the traditional industrial synthesis. A fructose to mannitol metabolic pathway, known as the mannitol cycle in fungi, has been discovered in a type of red algae (Caloglossa leprieurii), and it is highly possible that other microorganisms employ similar such pathways. A class of lactic acid bacteria, labeled heterofermentive because of their multiple fermentation pathways, convert either three fructose molecules or two fructose and one glucose molecule into two mannitol molecules, and one molecule each of lactic acid, acetic acid, and carbon dioxide. Feedstock syrups containing medium to large concentrations of fructose (for example, cashew apple juice, containing 55% fructose: 45% glucose) can produce yields 200 g (7.1 oz) mannitol per liter of feedstock. Further research is being conducted, studying ways to engineer even more efficient mannitol pathways in lactic acid bacteria, as well as the use of other microorganisms such as yeast and E. coli in mannitol production. When food-grade strains of any of the aforementioned microorganisms are used, the mannitol and the organism itself are directly applicable to food products, avoiding the need for careful separation of microorganism and mannitol crystals. Although this is a promising method, steps are needed to scale it up to industrially needed quantities.
Natural extraction
Since mannitol is found in a wide variety of natural products, including almost all plants, it can be directly extracted from natural products, rather than chemical or biological syntheses. In fact, in China, isolation from seaweed is the most common form of mannitol production. Mannitol concentrations of plant exudates can range from 20% in seaweeds to 90% in the plane tree. It is a constituent of saw palmetto (Serenoa).Traditionally, mannitol is extracted by the Soxhlet extraction, using ethanol, water, and methanol to steam and then hydrolysis of the crude material. The mannitol is then recrystallized from the extract, generally resulting in yields of about 18% of the original natural product. Another method of extraction is using supercritical and subcritical fluids. These fluids are at such a stage that no difference exists between the liquid and gas stages, so are more diffusive than normal fluids. This is considered to make them much more effective mass transfer agents than normal liquids. The super- or subcritical fluid is pumped through the natural product, and the mostly mannitol product is easily separated from the solvent and minute amount of byproduct.
Supercritical carbon dioxide extraction of olive leaves has been shown to require less solvent per measure of leaf than a traditional extraction – 141.7 g (5.00 oz) CO2 versus 194.4 g (6.86 oz) ethanol per 1 g (0.035 oz) olive leaf. Heated, pressurized, subcritical water is even cheaper, and is shown to have dramatically greater results than traditional extraction. It requires only 4.01 g (0.141 oz) water per 1 g (0.035 oz) of olive leaf, and gives a yield of 76.75% mannitol. Both super- and subcritical extractions are cheaper, faster, purer, and more environmentally friendly than the traditional extraction. However, the required high operating temperatures and pressures are causes for hesitancy in the industrial use of this technique.
History
Julije Domac elucidated the structure of hexene and mannitol obtained from Caspian manna. He determined the place of the double bond in hexene obtained from mannitol and proved that it is a derivative of a normal hexene. This also solved the structure of mannitol, which was unknown until then.
Controversy
The three studies that initially found that high-dose mannitol was effective in cases of severe head injury were the subject of an investigation published in 2007. Although several authors are listed with Dr. Julio Cruz, it is unclear whether the authors had knowledge of how the patients were recruited. Further, the Federal University of São Paulo, which Cruz gave as his affiliation, has never employed him. As a result of doubt surrounding Cruzs work, an updated version of the Cochrane review excludes all studies by Julio Cruz, leaving only four studies. Due to differences in selection of control groups, a conclusion about the clinical use of mannitol could not be reached.
Compendial status
British Pharmacopoeia
Japanese Pharmacopoeia
United States Pharmacopeia
See also
References
External links
Media related to Mannitol at Wikimedia Commons
"Mannitol". Drug Information Portal. U.S. National Library of Medicine. |
Bretylium | Bretylium (also bretylium tosylate) is an antiarrhythmic agent. It blocks the release of noradrenaline from nerve terminals. In effect, it decreases output from the peripheral sympathetic nervous system. It also acts by blocking K+ channels and is considered a class III antiarrhythmic. The dose is 5–10 mg/kg and side effects are high blood pressure followed by low blood pressure and ventricular ectopy.
Originally introduced in 1959 for the treatment of hypertension. Its use as an antiarrhythmic for ventricular fibrillation was discovered and patented by Marvin Bacaner in 1969 at the University of Minnesota.The American Heart Association removed bretylium from their 2000 ECC/ACC guidelines due to its unproven efficacy and ongoing supply problems. Many have cited these supply problems as an issue of raw materials needed in the production of Bretylium. By the release of the AHA 2005 ECC/ACC guidelines there is no mention of Bretylium and it is virtually unavailable throughout most of the world.On June 8, 2011 bretylium tosylate was announced as unavailable in the US after request of Hospira Inc. to withdraw its NDA from the market. Bretylium will remain on the FDAs discontinued drug list since its withdrawal was not the result of a safety or effectiveness concern. In mid 2019, it was reintroduced.
Uses
The drug was used in emergency medicine, cardiology, and other specialties throughout the 1980s-1990s for the acute management of ventricular tachycardia and ventricular fibrillation refractory to other first line treatments such as defibrillation or lidocaine.It is contraindicated in patients with AV (atrioventricular) heart block or digoxin toxicity.
Bretylium should be used only in an ICU or emergency department setting and should not be used elsewhere due to its dramatic actions and its predominant side effect of hypotension.
Experimental uses
It is used in physiological and pharmacological research as an inhibitor of sympathetic transmission. Its mechanism of action is the inhibition of neurotransmitter release from sympathetic nerve terminals, both by the inhibition of action potentials in the nerve terminals and by other mechanisms. Its specificity for sympathetic nerves is achieved because it is a substrate for the noradrenaline transporter; hence, it accumulates inside nerve terminals which have this transporter.
Synthesis
Quaternization of o-bromo-N,N-dimethylbenzylamine with ethyl-p-toluenesulfonate yields bretylium p-toluenesulfonate (tosylate).
== References == |
Hydrocodone/paracetamol | Hydrocodone/paracetamol (also known as hydrocodone/acetaminophen) is the combination of the pain medications hydrocodone and paracetamol (acetaminophen). It is used to treat moderate to severe pain. It is taken by mouth. Recreational use is common in the United States.Common side effects include dizziness, sleepiness, constipation, and vomiting. Serious side effects include addiction, decreased rate of breathing, low blood pressure, serotonin syndrome, severe allergic reactions, and liver failure. Use during pregnancy may harm the baby. Use with alcohol is not recommended. Hydrocodone works by binding to the mu-opioid receptor. How paracetamol works is unclear but may involve blocking the creation of prostaglandins.Hydrocodone/paracetamol was approved for medical use in the United States in 1982. In the United States, it is a schedule II controlled substance. In 2020, it was the sixteenth most commonly prescribed medication in the United States, with more than 30 million prescriptions. It is not available in the United Kingdom, though the combination codeine/paracetamol is. It is sold under the brand names Vicodin and Norco among others.
Uses
Medical
Hydrocodone/paracetamol is a fixed-dose combination consisting of the opioid hydrocodone and the non-opioid analgesic paracetamol. It is indicated for relief of moderate to severe pain of acute, chronic, or postoperative types. Hydrocodone/paracetamol comes in oral solution and tablet formulations; however strength of each component may vary. In October 2014, the Drug Enforcement Administration rescheduled hydrocodone combination drugs from schedule III to schedule II due to its risk for misuse, abuse, and diversions.
Recreational
Hydrocodone diversion and recreational use has escalated in recent years due to its opioid effects. In 2009 and 2010, hydrocodone was the second most frequently encountered opioid pharmaceutical in drug evidence submitted to U.S. federal, state, and local forensic laboratories as reported by DEAs National Forensic Laboratory Information System (NFLIS) and System to Retrieve Information from Drug Evidence (STRIDE).
Pregnancy and breastfeeding
Pregnancy category C: Risk in pregnancy cannot be ruled out. Animal controlled studies have not been conducted with this medication.Low concentrations of paracetamol is excreted through breast milk, however, hydrocodones excretion is unknown.
Kidney and liver impairment
Use with caution due to possible risk of toxicity.
Side effects
Most common
Lightheadedness
Dizziness
Euphoria
Sedation
Nausea and vomiting
Headaches
Less common
Central nervous system: drowsiness, confusion, lethargy, anxiety, fear, unease, dependence, mood changes, impairment of mental and physical performance
Gastrointestinal system: constipation
Genitourinary system: inability to urinate, bladder spasms
Respiratory depression: decreased rate and effort of breathing
Hearing impairment, permanent hearing loss
Dermatological: rash, itching
Black box warning
"Paracetamol has been associated with cases of acute liver failure, at times resulting in liver transplant or death. Most of the cases of liver injury are associated with the use of paracetamol at doses that exceed 4000 milligrams per day, and often involve more than one paracetamol-containing product."
Allergy warning
"Do not take hydrocodone bitartrate and paracetamol tablets if you are allergic to any of its ingredients. If you develop signs of allergy such as a rash or difficulty breathing stop taking hydrocodone bitartrate and paracetamol tablets and contact your healthcare provider immediately."
Overdose
Hydrocodone: Respiratory depression, extreme somnolence progressing towards coma, muscle limpness, cold and clammy skin, slow heart rate, low blood pressure, abrupt loss of heart function, and death may occur.Paracetamol: Liver and kidney failure, low blood sugar coma may occur.
Interactions
Hydrocodone may demonstrate an enhanced respiratory depressant effect when combined with other sedatives such as other opioids, benzodiazepines, nonbenzodiazepine sedatives, psychotropics, and anticonvulsants.Concurrent use of paracetamol with alcohol products may increase the risk of acute liver failure.
Monitoring
Laboratory function tests should be used to monitor therapy in people with severe liver or renal disease.
Pharmacology
Hydrocodone
Mechanism of action: Hydrocodone acts primarily as an agonist at the mu-opioid receptors, but is also a weak agonist against the delta opioid and kappa opioid receptors.
Absorption/distribution: The oral formulation can be absorbed from the gastrointestinal tract and remain 20–50% bound to plasma proteins. The onset of analgesia is about 20 to 30 minutes with duration of 4 to 8 hours and t1/2 of 3 to 4 hours.
Metabolism/excretion: It is metabolized to norhydrocodone by cytochrome P450 3A4 and to hydromorphone, also biologically active, by cytochrome P450 2D6. For individuals who have a defect in the gene encoding CYP2D6, the clearance of the drug will be lower and less metabolite such as hydromorphone will be formed; however, the effect on analgesia remains unknown.
Paracetamol
Mechanism of action: Paracetamol acts to inhibit COX enzyme, which is responsible for prostaglandin synthesis. Prostaglandins increase the perception of pain. Inhibition of prostaglandin production helps to alleviate pain.
Absorption/distribution: The half-life of oral paracetamol is 1.25 to 3 hours and peak level is reached by 10–60 minutes after ingestion.
Metabolism/excretion: Paracetamol is metabolized primarily in the liver via glucuronidation and sulfation to mostly non-toxic metabolites and some highly reactive metabolites, which is inactivated by glutathione. 85% of the oral dose is excreted renally. At high doses, the supply of glutathione cannot meet its demand, thus results in the accumulation of highly reactive compounds leading to liver damage.
Society and culture
In May 2017, professional golfer Tiger Woods was arrested by the police for driving under the influence. Woods said that this was due to four prescription drugs that he was taking for a back operation, one of which was Vicodin.
Legal status
On 30 June 2009, a U.S. Food and Drug Administration (FDA) advisory panel voted by a narrow margin to advise the FDA to remove Vicodin and another opioid, Percocet, from the market because of "a high likelihood of overdose from prescription narcotics and acetaminophen products". The panel also cited concerns of liver damage from their paracetamol component, which is also the main ingredient in commonly used nonprescription drugs such as Tylenol. Each year, paracetamol overdose is linked to about 400 deaths and 42,000 hospitalizations.In January 2011, the FDA asked manufacturers of prescription combination products that contain paracetamol to limit the amount of paracetamol to no more than 325 mg in each tablet or capsule within three years. The FDA also required manufacturers on all paracetamol containing products to issue a black box warning indicating the potential risk for severe liver injury and a warning highlighting potential for allergic reactions.On 22 August 2014, the Drug Enforcement Administration (DEA) announced that all hydrocodone combination products (HCPs) will be rescheduled from Schedule III to Schedule II of the Controlled Substances Act (CSA), effective on 6 October 2014. In 2010, more than 16,000 deaths were attributed to abuse of opioid drugs. Even though there are legitimate medical uses for HCPs, data suggest that a significant number of individuals misuse them.
Popular culture
Vicodin is mentioned in songs such as Juice Wrlds "Already Dead" Eminems "Kill You", Blackbears "Sniffing Vicodin in Paris", Kendrick Lamars "A.D.H.D", Futures "Lay Up", Lupe Fiascos "Mural", Queens of the Stone Ages "Feel Good Hit of the Summer", A Winged Victory for the Sullens "Steep Hills of Vicodin Tears", Death Gripss "Anne Bonny" and The Wombats "Give Me a Try". Vicodin use is a central theme in the 2004–2012 medical TV drama House, in which the lead character Dr. Gregory House is addicted to the drug combination.
Brand names
Brand names include Adol, Hycet, Lortab, Lorcet, Norco, and Vicodin among others.
See also
Hydrocodone/aspirin
Hydrocodone/ibuprofen
Oxycodone/paracetamol
References
External links
"Acetaminophen mixture with Hydrocodone bitartrate". Drug Information Portal. U.S. National Library of Medicine.
Vicodin U.S. Federal Regulations Archived 18 January 2017 at the Wayback Machine |
Ketorolac | Ketorolac, sold under the brand names Toradol, and Biorolac among others, is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain. Specifically it is recommended for moderate to severe pain. Recommended duration of treatment is less than six days. It is used by mouth, by nose, by injection into a vein or muscle, and as eye drops. Effects begin within an hour and last for up to eight hours.Common side effects include sleepiness, dizziness, abdominal pain, swelling, and nausea. Serious side effects may include stomach bleeding, kidney failure, heart attacks, bronchospasm, heart failure, and anaphylaxis. Use is not recommended during the last part of pregnancy or during breastfeeding. Ketorolac works by blocking cyclooxygenase 1 and 2 (COX1 and COX2), thereby decreasing production of prostaglandins.Ketorolac was patented in 1976 and approved for medical use in 1989. It is available as a generic medication. In 2018, it was the 192nd most commonly prescribed medication in the United States, with more than 3 million prescriptions.
Medical uses
Ketorolac is used for short-term management of moderate to severe pain. It is usually not prescribed for longer than five days,: 291 due to its potential to cause kidney damage.: 280 Ketorolac is effective when administered with paracetamol to control pain in newborns because it does not depress respiration as do opioids. Ketorolac is also an adjuvant to opioid medications and improves pain relief. It is also used to treat dysmenorrhea.: 291 Ketorolac is used to treat idiopathic pericarditis, where it reduces inflammation.For systemic use, ketorolac can be administered orally, under the tongue, by intramuscular injection, intravenously, and by nasal spray. Usually, it is initially administered by intramuscular injection or intravenously, with oral therapy used as a continuation after the initial IM or IV dose.Ketorolac is also used as an eye drop. It can be given during eye surgery to help with pain, and is effective in treating ocular itching. The eye drops are associated with decreased development of macular edema after cataract surgery. Ketorolac eye drops have also been used to manage pain from corneal abrasions.During treatment with ketorolac, clinicians monitor for the manifestation of adverse effects. Lab tests, such as liver function tests, bleeding time, BUN, serum creatinine and electrolyte levels are often used and help to identify potential complications.
Contraindications
Ketorolac is contraindicated in those with hypersensitivity, allergies to the medication, cross-sensitivity to other NSAIDs, prior to surgery, history of peptic ulcer disease, gastrointestinal bleeding, alcohol intolerance, renal impairment, cerebrovascular bleeding, nasal polyps, angioedema, and asthma. Recommendations exist for cautious use of ketorolac in those who have experienced cardiovascular disease, myocardial infarction, stroke, heart failure, coagulation disorders, renal impairment, and hepatic impairment.
Adverse effects
A common (>10%) side effect is drowsiness. Infrequent (<1%) side effects include paresthesia, prolonged bleeding time, injection site pain, purpura, sweating, abnormal thinking, increased production of tears, edema, pallor, dry mouth, abnormal taste, urinary frequency, increased liver enzymes, itching and others. Platelet function can be decreased by use of ketorolac.: 279 Though uncommon, potentially fatal adverse effects include stroke, myocardial infarction, GI bleeding, Stevens–Johnson syndrome, toxic epidermal necrolysis and anaphylaxis. In terms of safety, ketorolac has been assessed to be a relatively higher-risk NSAID when compared to aceclofenac, celecoxib, and ibuprofen.Like all NSAIDs, ketorolac can cause premature constriction of the ductus arteriosus in the infant if taken by the mother during the third trimester of pregnancy.In October 2020, the U.S. Food and Drug Administration (FDA) required the drug label to be updated for all nonsteroidal anti-inflammatory medications to describe the risk of kidney problems in unborn babies that result in low amniotic fluid. They recommend avoiding NSAIDs in pregnant women at 20 weeks or later in pregnancy.
Interactions
Ketorolac can interact with other medications. Probenecid can increase the probability of having an adverse reaction when taken with ketorolac. Pentoxifylline can increase the risk of bleeding. When aspirin is taken at the same time as ketorolac, the effectiveness is decreased. Problematic GI effects are additive and become more likely if potassium supplements, aspirin, other NSAIDs, corticosteroids, or alcohol is taken at the same time. The effectiveness of antihypertensives and diuretics can be lowered. The use of ketorolac can increase serum lithium levels to the point of toxicity. Toxicity to methotrexate is more likely if ketorolac is taken at the same time. The risk of bleeding increases with the concurrent medications clopidogrel, cefoperazone, valproic acid, cefotetan, eptifibatide, tirofiban, and ticlopidine. Anticoagulants and thrombolytic medications also increase the likelihood of bleeding. Medications used to treat cancer can interact with ketorolac along with radiation therapy. The risk of toxicity to the kidneys increases when ketorolac is taken with cyclosporine.Interactions with ketorolac also exist with some herbal supplements. The use of Panax ginseng, clove, ginger, arnica, feverfew, dong quai, chamomile, and Ginkgo biloba increases the risk of bleeding.
Mechanism of action
Chemically ketorolac functions as a carboxylic acid derivative serving non-selectively to block the prostaglandin synthesis by inhibition of prostaglandin G/H synthesis one and two. Prostaglandin functions in the body as a messenger for contraction/relaxation of smooth muscle and modulation of inflammation. Resultant, inhibition of prostaglandin synthesis prevents inflammation. The primary mechanism of action responsible for ketorolacs anti-inflammatory, antipyretic, and analgesic effects is the inhibition of prostaglandin synthesis by competitive blocking of the enzyme cyclooxygenase (COX). Ketorolac is a non-selective COX inhibitor. It is considered a first-generation NSAID.: 279
History
In the US, ketorolac is the only widely available intravenous NSAID.The Syntex company, of Palo Alto, California developed the ophthalmic solution Acular around 2006, which is currently licensed by Allergan, Inc.In 2007, there were concerns about the high incidence of reported side effects. This led to restriction in its dosage and maximum duration of use. In the UK, treatment was initiated only in a hospital, although this was not designed to exclude its use in prehospital care and mountain rescue settings. Dosing guidelines were published at that time.Concerns over the high incidence of reported side effects with ketorolac trometamol led to its withdrawal (apart from the ophthalmic formulation) in several countries, while in others its permitted dosage and maximum duration of treatment have been reduced. From 1990 to 1993, 97 reactions with a fatal outcome were reported worldwide.The eye-drop formulation was approved by the FDA in 1992.An intranasal formulation (Sprix) was approved by the FDA in 2010 for short-term management of moderate to moderately severe pain requiring analgesia at the opioid level.
Ketorolac has also been used in collegiate and professional sports, and is reported to be routinely used in the National Football League and National Hockey League. Competitive athletes, particularly in contact sports, are often expected by their coaches and/or teammates to play through injuries, generally with the help of painkillers. However, more recent research has indicated that encouraging players to play in an injured state tends to result in more severe injuries. A lawsuit alleging widespread league-sanctioned abuse of painkillers was filed by former players against the National Football League in 2017.
References
Further reading
External links
"Ketorolac". Drug Information Portal. U.S. National Library of Medicine. |
Valrubicin | Valrubicin (N-trifluoroacetyladriamycin-14-valerate, trade name Valstar) is a chemotherapy drug used to treat bladder cancer. Valrubicin is a semisynthetic analog of the anthracycline doxorubicin, and is administered by infusion directly into the bladder.
It was originally launched as Valstar in the U.S. in 1999 for intravesical therapy of Bacille Calmette-Guérin (BCG)-refractory carcinoma in situ of the urinary bladder in patients in whom cystectomy would be associated with unacceptable morbidity or mortality; however, it was voluntarily withdrawn in 2002 due to manufacturing issues. Valstar was relaunched on September 3, 2009.
Side effects
Blood in urine
Incontinence
painful or difficult urination
Unusually frequent urination
== References == |
Amoxicillin | Amoxicillin is an antibiotic medication used to treat a number of bacterial infections. These include middle ear infection, strep throat, pneumonia, skin infections, and urinary tract infections among others. It is taken by mouth, or less commonly by injection.Common adverse effects include nausea and rash. It may also increase the risk of yeast infections and, when used in combination with clavulanic acid, diarrhea. It should not be used in those who are allergic to penicillin. While usable in those with kidney problems, the dose may need to be decreased. Its use in pregnancy and breastfeeding does not appear to be harmful. Amoxicillin is in the beta-lactam family of antibiotics.Amoxicillin was discovered in 1958 and came into medical use in 1972. Amoxil was approved for medical use in the United States in 1974, and in the United Kingdom in 1977. It is on the (WHO) World Health Organizations List of Essential Medicines. It is one of the most commonly prescribed antibiotics in children. Amoxicillin is available as a generic medication. In 2020, it was the 40th most commonly prescribed medication in the United States, with more than 15 million prescriptions.
Medical uses
Amoxicillin is used in the treatment of a number of infections, including acute otitis media, streptococcal pharyngitis, pneumonia, skin infections, urinary tract infections, Salmonella infections, Lyme disease, and chlamydia infections.
Acute otitis media
Children with acute otitis media who are younger than six months of age are generally treated with amoxicillin or other antibiotics. Although most children with acute otitis media who are older than two years old do not benefit from treatment with amoxicillin or other antibiotics, such treatment may be helpful in children younger than two years old with acute otitis media that is bilateral or accompanied by ear drainage. In the past, amoxicillin was dosed three times daily when used to treat acute otitis media, which resulted in missed doses in routine ambulatory practice. There is now evidence that two times daily dosing or once daily dosing has similar effectiveness.
Respiratory infections
Amoxicillin and amoxicillin-clavulanate have been recommended by guidelines as the drug of choice for bacterial sinusitis and other respiratory infections. Most sinusitis infections are caused by viruses, for which amoxicillin and amoxicillin-clavulanate are ineffective, and the small benefit gained by amoxicillin may be overridden by the adverse effects.
Amoxicillin is recommended as the preferred first-line treatment for community-acquired pneumonia in adults by the National Institute for Health and Care Excellence, either alone (mild to moderate severity disease) or in combination with a macrolide. The World Health Organization (WHO) recommends amoxicillin as first-line treatment for pneumonia that is not "severe". Amoxicillin is used in post-exposure inhalation of anthrax to prevent disease progression and for prophylaxis.
H. pylori
It is effective as one part of a multi-drug regimen for treatment of stomach infections of Helicobacter pylori. It is typically combined with a proton-pump inhibitor (such as omeprazole) and a macrolide antibiotic (such as clarithromycin); other drug combinations are also effective.
Lyme borreliosis
Amoxicillin is effective for treatment of early cutaneous Lyme borreliosis; the effectiveness and safety of oral amoxicillin is neither better nor worse than common alternatively-used antibiotics.
Skin infections
Amoxicillin is occasionally used for the treatment of skin infections, such as acne vulgaris. It is often an effective treatment for cases of acne vulgaris that have responded poorly to other antibiotics, such as doxycycline and minocycline.
Infections in infants in resource-limited settings
Amoxicillin is recommended by the World Health Organization for the treatment of infants with signs and symptoms of pneumonia in resource-limited situations when the parents are unable or unwilling to accept hospitalization of the child. Amoxicillin in combination with gentamicin is recommended for the treatment of infants with signs of other severe infections when hospitalization is not an option.
Prevention of bacterial endocarditis
It is also used to prevent bacterial endocarditis and as a pain-reliever in high-risk people having dental work done, to prevent Streptococcus pneumoniae and other encapsulated bacterial infections in those without spleens, such as people with sickle-cell disease, and for both the prevention and the treatment of anthrax. The United Kingdom recommends against its use for infectious endocarditis prophylaxis. These recommendations do not appear to have changed the rates of infection for infectious endocarditis.
Combination treatment
Amoxicillin is susceptible to degradation by β-lactamase-producing bacteria, which are resistant to most β-lactam antibiotics, such as penicillin. For this reason, it may be combined with clavulanic acid, a β-lactamase inhibitor. This drug combination is commonly called co-amoxiclav.
Spectrum of activity
It is a moderate-spectrum, bacteriolytic, β-lactam antibiotic in the aminopenicillin family used to treat susceptible Gram-positive and Gram-negative bacteria. It is usually the drug of choice within the class because it is better-absorbed, following oral administration, than other β-lactam antibiotics.
In general, Streptococcus, Bacillus subtilis, Enterococcus, Haemophilus, Helicobacter, and Moraxella are susceptible to amoxicillin, whereas Citrobacter, Klebsiella and Pseudomonas aeruginosa are resistant to it. Some E. coli and most clinical strains of Staphylococcus aureus have developed resistance to amoxicillin to varying degrees.
Adverse effects
Adverse effects are similar to those for other β-lactam antibiotics, including nausea, vomiting, rashes, and antibiotic-associated colitis. Loose bowel movements (diarrhea) may also occur. Rarer adverse effects include mental changes, lightheadedness, insomnia, confusion, anxiety, sensitivity to lights and sounds, and unclear thinking. Immediate medical care is required upon the first signs of these adverse effects.The onset of an allergic reaction to amoxicillin can be very sudden and intense; emergency medical attention must be sought as quickly as possible. The initial phase of such a reaction often starts with a change in mental state, skin rash with intense itching (often beginning in fingertips and around groin area and rapidly spreading), and sensations of fever, nausea, and vomiting. Any other symptoms that seem even remotely suspicious must be taken very seriously. However, more mild allergy symptoms, such as a rash, can occur at any time during treatment, even up to a week after treatment has ceased. For some people allergic to amoxicillin, the adverse effects can be fatal due to anaphylaxis.Use of the amoxicillin/clavulanic acid combination for more than one week has caused a drug-induced immunoallergic-type hepatitis in some patients. Young children having ingested acute overdoses of amoxicillin manifested lethargy, vomiting, and renal dysfunction.There is poor reporting of adverse effects of amoxicillin from clinical trials. For this reason, the severity and frequency of adverse effects from amoxicillin is probably higher than reported from clinical trials.
Nonallergic rash
Between 3 and 10% of children taking amoxicillin (or ampicillin) show a late-developing (>72 hours after beginning medication and having never taken penicillin-like medication previously) rash, which is sometimes referred to as the "amoxicillin rash". The rash can also occur in adults and may rarely be a component of the DRESS syndrome.The rash is described as maculopapular or morbilliform (measles-like; therefore, in medical literature, it is called "amoxicillin-induced morbilliform rash".). It starts on the trunk and can spread from there. This rash is unlikely to be a true allergic reaction and is not a contraindication for future amoxicillin usage, nor should the current regimen necessarily be stopped. However, this common amoxicillin rash and a dangerous allergic reaction cannot easily be distinguished by inexperienced persons, so a healthcare professional is often required to distinguish between the two.A nonallergic amoxicillin rash may also be an indicator of infectious mononucleosis. Some studies indicate about 80-90% of patients with acute Epstein Barr virus infection treated with amoxicillin or ampicillin develop such a rash.
Interactions
Amoxicillin may interact with these drugs:
Anticoagulants (dabigatran, warfarin).
Cancer treatment (methotrexate).
Uricosuric drugs.
Typhoid vaccine
Probenecid reduces renal excretion and increases the blood levels of amoxicillin.
Oral contraceptives may become less effective.
Allopurinol (gout treatment).
Pharmacology
Amoxicillin (α-amino-p-hydroxybenzyl penicillin) is a semisynthetic derivative of penicillin with a structure similar to ampicillin but with better absorption when taken by mouth, thus yielding higher concentrations in blood and in urine. Amoxicillin diffuses easily into tissues and body fluids. It will cross the placenta and is excreted into breastmilk in small quantities. It is metabolized by the liver and excreted into the urine. It has an onset of 30 minutes and a half-life of 3.7 hours in newborns and 1.4 hours in adults.Amoxicillin attaches to the cell wall of susceptible bacteria and results in their death. It also is a bactericidal compound. It is effective against streptococci, pneumococci, enterococci, Haemophilus influenzae, Escherichia coli, Proteus mirabilis, Neisseria meningitidis, Neisseria gonorrhoeae, Shigella, Chlamydia trachomatis, Salmonella, Borrelia burgdorferi, and Helicobacter pylori. As a derivative of ampicillin, amoxicillin is a member of the penicillin family and, like penicillins, is a β-lactam antibiotic. It inhibits cross-linkage between the linear peptidoglycan polymer chains that make up a major component of the bacterial cell wall.
It has two ionizable groups in the physiological range (the amino group in alpha-position to the amide carbonyl group and the carboxyl group).
History
Amoxicillin was one of several semisynthetic derivatives of 6-aminopenicillanic acid (6-APA) developed by the Beecham Group in the 1960s. It became available in 1972 and was the second aminopenicillin to reach the market (after ampicillin in 1961). Co-amoxiclav became available in 1981.
Society and culture
Economics
Amoxicillin is relatively inexpensive.
Modes of delivery
Pharmaceutical manufacturers make amoxicillin in trihydrate form, for oral use available as capsules, regular, chewable and dispersible tablets, syrup and pediatric suspension for oral use, and as the sodium salt for intravenous administration.An extended-release is available. The intravenous form of amoxicillin is not sold in the United States. When an intravenous aminopenicillin is required in the United States, ampicillin is typically used. When there is an adequate response to ampicillin, the course of antibiotic therapy may often be completed with oral amoxicillin.Research with mice indicated successful delivery using intraperitoneally injected amoxicillin-bearing microparticles.
Names
"Amoxicillin" is the International Nonproprietary Name (INN), British Approved Name (BAN), and United States Adopted Name (USAN), while "amoxycillin" is the Australian Approved Name (AAN).Amoxicillin is one of the semisynthetic penicillins discovered by Beecham scientists. The patent for amoxicillin has expired, thus amoxicillin and co-amoxiclav preparations are marketed under various brand names across the world.
Veterinary uses
Amoxicillin is also sometimes used as an antibiotic for animals. The use of amoxicillin for animals intended for human consumption (chickens, cattle, and swine for example) has been approved.
References
Further reading
Neal MJ (2002). Medical Pharmacology at a Glance (4th ed.). Oxford: Blackwell Science. ISBN 978-0-632-05244-8.
External links
"Amoxicillin". Drug Information Portal. U.S. National Library of Medicine. |
Suxamethonium chloride | Suxamethonium chloride, also known as suxamethonium or succinylcholine, or simply sux by medical abbreviation, is a medication used to cause short-term paralysis as part of general anesthesia. This is done to help with tracheal intubation or electroconvulsive therapy. It is administered by injection, either into a vein or into a muscle. When used in a vein, onset of action is generally within one minute and effects last for up to 10 minutes.Common side effects include low blood pressure, increased saliva production, muscle pain, and rash. Serious side effects include malignant hyperthermia and allergic reactions. It is not recommended in people who are at risk of high blood potassium or a history of myopathy. Use during pregnancy appears to be safe for the baby. Suxamethonium is in the neuromuscular blocker family of medications and is of the depolarizing type. It works by blocking the action of acetylcholine on skeletal muscles. Side effects of succinylcholine chloride injection include anaphylaxis, hyperkalemia, and malignant hyperthermia.Suxamethonium was described as early as 1906 and came into medical use in 1951. It is on the World Health Organizations List of Essential Medicines. Suxamethonium is available as a generic medication. It may colloquially be referred to as "sux".
Medical uses
Succinylcholine chloride injection is indicated, in addition to general anesthesia, to facilitate tracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical ventilation.Its medical uses are limited to short-term muscle relaxation in anesthesia and intensive care, usually for facilitation of endotracheal intubation. It is popular in emergency medicine due to its rapid onset and brief duration of action. The former is a major point of consideration in the context of trauma care, where endotracheal intubation may need to be completed very quickly. The latter means that, should attempts at endotracheal intubation fail and the person cannot be ventilated, there is a prospect for neuromuscular recovery and the onset of spontaneous breathing before low blood oxygen levels occurs. It may be better than rocuronium in people without contraindications due to its faster onset of action and shorter duration of action.Suxamethonium is also commonly used as the sole muscle relaxant during electroconvulsive therapy, favoured for its short duration of action.Suxamethonium is quickly degraded by plasma butyrylcholinesterase and the duration of effect is usually in the range of a few minutes. When plasma levels of butyrylcholinesterase are greatly diminished or an atypical form is present (an otherwise harmless inherited disorder), paralysis may last much longer, as is the case in liver failure or in neonates.It is recommended that the vials be stored at a temperature between 2°-8 °C. The multi-dose vials are stable for up to 14 days at room temperature without significant loss of potency. Unless otherwise indicated in the prescribing information, room temperature for storage of medications is 15°-25 °C (59°-77 °F).
Side effects
Side effects include malignant hyperthermia, muscle pains, acute rhabdomyolysis with high blood levels of potassium, transient ocular hypertension, constipation and changes in cardiac rhythm, including slow heart rate, and cardiac arrest. In people with neuromuscular disease or burns, an injection of suxamethonium can lead to a large release of potassium from skeletal muscles, potentially resulting in cardiac arrest. Conditions having susceptibility to suxamethonium-induced high blood potassium are burns, closed head injury, acidosis, Guillain–Barré syndrome, cerebral stroke, drowning, severe intra-abdominal sepsis, massive trauma, myopathy, and tetanus.
Suxamethonium does not produce unconsciousness or anesthesia, and its effects may cause considerable psychological distress while simultaneously making it impossible for a patient to communicate. Therefore, administration of the drug to a conscious patient is contraindicated.
Hyperkalemia
The side effect of high blood potassium may occur because the acetylcholine receptor is propped open, allowing continued flow of potassium ions into the extracellular fluid. A typical increase of potassium ion serum concentration on administration of suxamethonium is 0.5 mmol per liter. The increase is transient in otherwise healthy patients. The normal range of potassium is 3.5 to 5 mEq per liter. High blood potassium does not generally result in adverse effects below a concentration of 6.5 to 7 mEq per liter. Therefore, the increase in serum potassium level is usually not catastrophic in otherwise healthy patients. Severely high blood levels of potassium can cause changes in cardiac electrophysiology, which, if severe, can result in arrhythmias and even cardiac arrest.
Malignant hyperthermia
Malignant hyperthermia (MH) from suxamethonium administration can result in a drastic and uncontrolled increase in skeletal muscle oxidative metabolism. This overwhelms the bodys capacity to supply oxygen, remove carbon dioxide, and regulate body temperature, eventually leading to circulatory collapse and death if not treated quickly.
Susceptibility to malignant hyperthermia is often inherited as an autosomal dominant disorder, for which there are at least six genetic loci of interest, the most prominent being the ryanodine receptor gene (RYR1). MH susceptibility is phenotype and genetically related to central core disease (CCD), an autosomal dominant disorder characterized both by MH symptoms and by myopathy. MH is usually unmasked by anesthesia, or when a family member develops the symptoms. There is no simple, straightforward test to diagnose the condition. When MH develops during a procedure, treatment with dantrolene sodium is usually initiated; dantrolene and the avoidance of suxamethonium administration in susceptible people have markedly reduced the mortality from this condition.
Apnea
The normal short duration of action of suxamethonium is due to the rapid metabolism of the drug by non-specific plasma cholinesterases. However plasma cholinesterase activity is reduced in some people due to either genetic variation or acquired conditions, which results in a prolonged duration of neuromuscular block. Genetically, ninety six percent of the population have a normal (Eu:Eu) genotype and block duration; however, some people have atypical genes (Ea, Es, Ef) which can be found in varying combinations with the Eu gene, or other atypical genes (see Pseudocholinesterase deficiency). Such genes will result in a longer duration of action of the drug, ranging from 20 minutes up to several hours. Acquired factors that affect plasma cholinesterase activity include pregnancy, liver disease, kidney failure, heart failure, thyrotoxicosis, and cancer, as well as a number of other drugs.If unrecognized by a clinician it could lead to awareness if anesthesia is discontinued whilst still paralyzed or hypoxemia (and potentially fatal consequences) if artificial ventilation is not maintained. Normal treatment is to maintain sedation and ventilate the patient on an intensive care unit until muscle function has returned. Blood testing for cholinesterase function can be performed.Mivacurium, a non-depolarizing neuromuscular blocking drug, is also metabolized via the same route with a similar clinical effect in patients deficient in plasma cholinesterase activity.Deliberate induction of conscious apnea using this drug led to its use as a form of aversion therapy in the 1960s and 1970s in some prison and institutional settings. This use was discontinued after negative publicity concerning the terrifying effects on subjects of this treatment and ethical questions about the punitive use of painful aversion.
Mechanism of action
There are two phases to the blocking effect of suxamethonium.
Phase 1 block
Phase 1 blocking has the principal paralytic effect. Binding of suxamethonium to the nicotinic acetylcholine receptor results in opening of the receptors monovalent cation channel; a disorganized depolarization of the motor end-plate occurs and calcium is released from the sarcoplasmic reticulum.
In normal skeletal muscle, acetylcholine dissociates from the receptor following depolarization and is rapidly hydrolyzed by acetylcholinesterase. The muscle cell is then ready for the next signal.
Suxamethonium has a longer duration of effect than acetylcholine, and is not hydrolyzed by acetylcholinesterase. By maintaining the membrane potential above threshold, it does not allow the muscle cell to repolarize. When acetylcholine binds to an already depolarized receptor, it cannot cause further depolarization.
Calcium is removed from the muscle cell cytoplasm independent of repolarization (depolarization signaling and muscle contraction are independent processes). As the calcium is taken up by the sarcoplasmic reticulum, the muscle relaxes. This explains muscle flaccidity rather than tetany following fasciculations.
The results are membrane depolarization and transient fasciculations, followed by paralysis.
Phase 2 block
While this phase is not abnormal and is a part of its mechanism of action, it is undesirable during surgery, due to the inability to depolarize the cell again. Often, patients must be on a ventilator for hours if Phase 2 block occurs. It is caused by the blood concentration of suxamethonium exceeding the therapeutic window. Desensitization occurs at the nerve terminal, and the myocyte becomes less sensitive to acetylcholine; the membrane repolarizes and cannot be depolarized again.
Chemistry
Suxamethonium is an odorless, white crystalline substance. Aqueous solutions have a pH of about 4. The dihydrate melts at 160 °C, whereas the anhydrous melts at 190 °C. It is highly soluble in water (1 gram in about 1 mL), soluble in ethyl alcohol (1 gram in about 350 mL), slightly soluble in chloroform, and practically insoluble in ether. Suxamethonium is a hygroscopic compound. The compound consists of two acetylcholine molecules that are linked by their acetyl groups. It can also be viewed as a central moiety of succinic acid with two choline moieties, one on each end.
History
Suxamethonium was first discovered in 1906 by Reid Hunt and René de M. Taveau. When studying the drug, animals were given curare and thus they missed the neuromuscular blocking properties of suxamethonium. Instead in 1949 an Italian group led by Daniel Bovet was first to describe succinylcholine induced paralysis. The clinical introduction of suxamethonium was described in 1951 by several groups. Papers published by Stephen Thesleff and Otto von Dardel in Sweden are important but also to be mentioned is work by Bruck, Mayrhofer and Hassfurther in Austria, Scurr and Bourne in UK, and Foldes in America.
Abuse
Dubai authorities deem that the murder of Hamas operative Mahmoud al-Mabhouh was carried out on their soil by Mossad agents with the use of suxamethonium chloride injection. Entering Dubai under false passports in 2010, the Mossad agents found al-Mabhouh at a hotel, immobilized him with the drug, electrocuted him, then suffocated him by pillow in an assassination. A high concentration of suxamethonium chloride was found in al-Mabhouhs body post-mortem. The incident triggered significant diplomatic crises in the Middle East, Europe, and Australia.It was used by serial killer Efren Saldivar (1988-1998), and in the murder of Kathy Augustine (2006).
Brand names
It is available in German-speaking countries under the trade name Lysthenon among others.
Other animals
It is sometimes used in combination with pain medications and sedatives for euthanasia and immobilization of horses.
References
External links
"Suxamethonium Chloride". Drug Information Portal. U.S. National Library of Medicine. |
Renova | Renova may refer to:
Cities, towns, townships etc.
Renova, Mississippi
Renova: an unincorporated settlement in Dexter Township, Minnesota
Brand names
Renova (brand), a Portuguese paper products company
Trade name of tretinoin, a treatment for acne and other skin conditions
Renova Group, a Russian holding company controlled by Viktor Vekselberg
Other
FK Renova, football club
Renova (fish), a killifish genus |
Zolmitriptan | Zolmitriptan, sold under the brand name Zomig among others, is a triptan used in the acute treatment of migraine attacks with or without aura and cluster headaches. It is a selective serotonin receptor agonist of the 1B and 1D subtypes.
It was patented in 1990 and approved for medical use in 1997.
Medical uses
Zolmitriptan is used for the acute treatment of migraines with or without aura in adults. Zolmitriptan is not intended for the prophylactic therapy of migraine or for use in the management of hemiplegic or basilar migraine.
Zolmitriptan is available as a swallowable tablet, an oral disintegrating tablet, and a nasal spray, in doses of 2.5 and 5 mg. People who get migraines from aspartame should not use the disintegrating tablet (Zomig ZMT), which contains aspartame.A 2014 Cochrane review has shown that zolmitriptan 5 mg nasal spray was significantly more effective than the 5 mg oral tablet.According to a study of healthy volunteers, food intake seems to have no significant effect on the effectiveness of Zolmitriptan in both men and women.Off-label Uses:
Acute treatment of cluster headaches—Level A recommendation from the American Academy of Neurology
Acute treatment of menstrual migraine
Adverse reactions
As for cardiovascular side effects, zolmitriptan can increase systolic blood pressure in the elderly and increase diastolic blood pressure in both the elderly and young people. Additionally, there is the side effect of a dose-related increase in sedation. There is a risk of headaches caused by medication withdrawal or medication overuse.Zolmitriptan has a weak affinity for 5-HT 1A receptors; these receptors have implications in the development of serotonin syndrome.Following administration of cimetidine, the half-life and AUC of zolmitriptan and its active metabolites were approximately doubled (see CLINICAL PHARMACOLOGY in product pamphlet).
Contraindications
Zolmitriptan is contraindicated in patients with cerebrovascular or cardiovascular disease because 5-HT 1B receptors are present in coronary arteries. Such conditions include, but are not limited to, coronary artery disease, stroke, and peripheral vascular disease.It is also contraindicated in hemiplegic migraine.
Mechanism of action
Zolmitriptan is a selective 5-hydroxytryptamine 1B/1D receptor agonist with a weak affinity for the 5-HT 1A receptor subtypes. Its action on 5-HT 1B/1D receptors causes vasoconstriction in intracranial blood vessels; as well it can inhibit the release of pro-inflammatory neuropeptides from trigeminal perivascular nerve endings. It crosses the blood-brain-barrier as evidenced by the presence of radioactive [3H]-zolmitriptan labels within the cells of the trigeminal nucleus caudalis and nucleus tractus solitaries.
Pharmacokinetics
Zolmitriptan has a rapid onset of action and has been detected in the brain as early as within 5 minutes of intranasal administration. On average, zolmitriptan has an oral bioavailability of 40%, a mean volume of distribution of 8.3 L/kg after oral administration, and 2.4L/kg after intravenous administration.Zolmitriptan is metabolized into three major metabolites by the human hepatic cytochrome P450 enzymes—primarily CYP1A2. Two-thirds of the parent compound breaks down into the active metabolite N-desmethyl-zolmitriptan (183C91), while the remaining one-third separates into the other two inactive metabolites: zolmitriptan N-oxide and an indole acetic acid derivative. It has an elimination half-life of about three hours before it undergoes renal elimination; its clearance is greater than the glomerular filtration rate suggesting that there is some renal tubular secretion of the compound.
Economics
Brand names
Zolmitriptan is marketed by AstraZeneca with the brand names Zomig, Zomigon (Argentina, Canada & Greece), AscoTop (Germany) and Zomigoro (France).
Economics
In 2008, Zomig generated nearly $154 million in sales.AstraZenecas U.S. patent on Zomig tablets expired on November 14, 2012, and its pediatric exclusivity extension expired on May 14, 2013. The patent in certain European countries has already expired too, and generic drug maker Actavis released a generic version in those countries, starting in March 2012.
Legal status
In Russia versions of zolmitriptan, which are not registered in the National registry of medications, may be regarded as narcotic drugs (derivatives of dimethyltriptamine).
References
Further reading
MacGregor EA (1998). "Zolmitriptan clinical studies". Drugs Today. 34 (12): 1027–1033. doi:10.1358/dot.1998.34.12.487488. PMID 14743270.
External links
"Zolmitriptan". Drug Information Portal. U.S. National Library of Medicine.
"Zolmitriptan Nasal Spray". MedlinePlus. |
Infigratinib | Infigratinib, sold under the brand name Truseltiq, is an anti-cancer medication used to treat cholangiocarcinoma (bile duct cancer).Infigratinib is a kinase inhibitor targeting the fibroblast growth factor receptors FGFR1, FGFR2 and FGFR3 It was designated an orphan drug by the U.S. Food and Drug Administration (FDA) in 2019, and it was approved for medical use in the United States in May 2021.
Medical uses
Infigratinib is indicated for the treatment of adults with previously treated, unresectable locally advanced or metastatic cholangiocarcinoma (bile duct cancer) with a fibroblast growth factor receptor 2 (FGFR2) fusion or other rearrangement as detected by an FDA-approved test.
References
External links
"Infigratinib". Drug Information Portal. U.S. National Library of Medicine.
Clinical trial number NCT02150967 for "A Phase II, Single Arm Study of BGJ398 in Patients With Advanced Cholangiocarcinoma" at ClinicalTrials.gov |
Octreotide | Octreotide, sold under the brand name Sandostatin among others, is an octapeptide that mimics natural somatostatin pharmacologically, though it is a more potent inhibitor of growth hormone, glucagon, and insulin than the natural hormone. It was first synthesized in 1979 by the chemist Wilfried Bauer, and binds predominantly to the somatostatin receptors SSTR2 and SSTR5. It was approved for use in the United States in 1988.
Medical uses
Tumors
Octreotide is used for the treatment of growth hormone producing tumors (acromegaly and gigantism), when surgery is contraindicated, pituitary tumors that secrete thyroid-stimulating hormone (thyrotropinoma), diarrhea and flushing episodes associated with carcinoid syndrome, and diarrhea in people with vasoactive intestinal peptide-secreting tumors (VIPomas). Octreotide is also used in mild cases of glucagonoma when surgery is not an option.
Bleeding esophageal varices
Octreotide is often given as an infusion for management of acute hemorrhage from esophageal varices in liver cirrhosis on the basis that it reduces portal venous pressure, though current evidence suggests that this effect is transient and does not improve survival.
Radiolabeling
Octreotide is used in nuclear medicine imaging by labeling with indium-111 (Octreoscan) to noninvasively image neuroendocrine and other tumours expressing somatostatin receptors. More recently, it has been radiolabeled with carbon-11 as well as gallium-68 (using edotreotide), enabling imaging with positron emission tomography (PET), which provides higher resolution and sensitivity.
Octreotide (usually as the derivative edotreotide or DOTATOC) can also be labeled with a variety of therapeutic radionuclides, such as yttrium-90 or lutetium-177, to enable peptide receptor radionuclide therapy (PRRT) for the treatment of unresectable neuroendocrine tumours.
Acromegaly
Octreotide can also be used in the treatment of acromegaly, a disorder of excessive growth hormone (GH). Octreotide, being a somatostatin analog, inhibits the release of GH from the pituitary gland through a process normally involved in negative feedback.
In June 2020, Mycapssa (octreotide) was approved for medical use in the United States with an indication for the long-term maintenance treatment in acromegaly patients who have responded to and tolerated treatment with octreotide or lanreotide. Mycapssa is the first and only oral somatostatin analog (SSA) approved by the FDA.
Gastrointestinal fistulae
Octreotide helps in management of the fistula by reducing gastrointestinal secretions and inhibiting gastrointestinal motility, thus controlling and reducing its output. The value in healing intestinal fistulas is yet to be proven and routine use is limited because of the side effects.
Hypoglycemia
Octreotide is also used in the treatment of refractory hypoglycemia in neonates and sulphonylurea-induced hypoglycemia in adults.
It is useful in overdose management of sulfonylurea type antidiabetic medications, when recurrent or refractory to parenteral dextrose. Mechanism of action is the suppression of insulin secretion.
Gastrointestinal secretions
Octreotide is used in the palliative care setting to reduce gastrointestinal secretions, with the intention of alleviating vomiting associated with bowel obstruction.
Contraindications
Octreotide has not been adequately studied for the treatment of children as well as pregnant and lactating women. The drug is given to these groups only if a risk-benefit analysis is positive.
Adverse effects
The most common adverse effects are headache, hypothyroidism, cardiac conduction changes, gastrointestinal reactions (including cramps, nausea/vomiting and diarrhoea or constipation), gallstones, reduction of insulin release, hyperglycemia or sometimes hypoglycemia, and (usually transient) injection site reactions. Slow heart rate, skin reactions such as pruritus, hyperbilirubinemia, hypothyroidism, dizziness and dyspnoea are also fairly common (more than 1%). Rare side effects include acute anaphylactic reactions, pancreatitis and hepatitis.Some studies reported alopecia in those who were treated by octreotide. Rats which were treated by octreotide experienced erectile dysfunction in a 1998 study.A prolonged QT interval has been observed, but it is uncertain whether this is a reaction to the drug or the result of an existing illness.
Interactions
Octreotide can reduce the intestinal reabsorption of ciclosporin, possibly making it necessary to increase the dose. People with diabetes mellitus might need less insulin or oral antidiabetics when treated with octreotide, as it inhibits glucagon secretion more strongly and for a longer time span than insulin secretion. The bioavailability of bromocriptine is increased; besides being an antiparkinsonian, bromocriptine is also used for the treatment of acromegaly.
Pharmacology
Since octreotide resembles somatostatin in physiological activities, it can:
inhibit secretion of many hormones, such as gastrin, cholecystokinin, glucagon, growth hormone, insulin, secretin, pancreatic polypeptide, TSH, and vasoactive intestinal peptide,
reduce secretion of fluids by the intestine and pancreas,
reduce gastrointestinal motility and inhibit contraction of the gallbladder,
inhibit the action of certain hormones from the anterior pituitary,
cause vasoconstriction in the blood vessels, and
reduce portal vessel pressures in bleeding varices.It has also been shown to produce analgesic effects, most probably acting as a partial agonist at the mu opioid receptor.
Pharmacokinetics
Octreotide is absorbed quickly and completely after subcutaneous application. Maximal plasma concentration is reached after 30 minutes. The elimination half-life is 100 minutes (1.7 hours) on average when applied subcutaneously; after intravenous injection, the substance is eliminated in two phases with half-lives of 10 and 90 minutes, respectively.
History
Octreotide acetate was approved for use in the United States in 1988.In January 2020, approval of octreotide acetate in the United States was granted to Sun Pharmaceutical under the brand name Bynfezia Pen for the treatment of:
the reduction of growth hormone and insulin-like growth factor 1 (somatomedin C) in adults with acromegaly who have had inadequate response to or cannot be treated with surgical resection, pituitary irradiation, and bromocriptine mesylate at maximally tolerated doses
severe diarrhea/flushing episodes associated with metastatic carcinoid tumors in adults
profuse watery diarrhea associated with vasoactive intestinal peptide tumors (VIPomas) in adults
Society and culture
Legal status
On 15 September 2022, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Mycapssa, intended for the treatment of adults with acromegaly. The applicant for this medicinal product is Amryt Pharmaceuticals DAC.
Research
Octreotide has also been used off-label for the treatment of severe, refractory diarrhea from other causes. It is used in toxicology for the treatment of prolonged recurrent hypoglycemia after sulfonylurea and possibly meglitinide overdose. It has also been used with varying degrees of success in infants with nesidioblastosis to help decrease insulin hypersecretion. Several clinical trials have demonstrated the effect of octreotide as acute treatment (abortive agent) in cluster headache, where it has been shown that administration of subcutaneous octreotide is effective when compared with placebo.Octreotide has also been investigated in people with pain from chronic pancreatitis.It has been used in the treatment of malignant bowel obstruction.Octreotide may be used in conjunction with midodrine to partially reverse peripheral vasodilation in the hepatorenal syndrome. By increasing systemic vascular resistance, these drugs reduce shunting and improve renal perfusion, prolonging survival until definitive treatment with liver transplant. Similarly, octreotide can be used to treat refractory chronic hypotension.While successful treatment has been demonstrated in case reports, larger studies have failed to demonstrate efficacy in treating chylothorax.A small study has shown that octreotide may be effective in the treatment of idiopathic intracranial hypertension.
Obesity
Octreotide has been used experimentally to treat obesity, particularly obesity caused by lesions in the hunger and satiety centers of the hypothalamus, a region of the brain central to the regulation of food intake and energy expenditure. The circuit begins with an area of the hypothalamus, the arcuate nucleus, that has outputs to the lateral hypothalamus (LH) and ventromedial hypothalamus (VMH), the brains feeding and satiety centers, respectively. The VMH is sometimes injured by ongoing treatment for acute lymphoblastic leukemia (ALL) or surgery or radiation to treat posterior cranial fossa tumors. With the VMH disabled and no longer responding to peripheral energy balance signals, "Efferent sympathetic activity drops, resulting in malaise and reduced energy expenditure, and vagal activity increases, resulting in increased insulin secretion and adipogenesis." "VMH dysfunction promotes excessive caloric intake and decreased caloric expenditure, leading to continuous and unrelenting weight gain. Attempts at caloric restriction or pharmacotherapy with adrenergic or serotonergic agents have previously met with little or only brief success in treating this syndrome." In this context, octreotide suppresses the excessive release of insulin and may increase its action, thereby inhibiting excessive adipose storage. In a small clinical trial in eighteen pediatric subjects with intractable weight gain following therapy for ALL or brain tumors and other evidence of hypothalamic dysfunction, octreotide reduced body mass index (BMI) and insulin response during glucose tolerance test, while increasing parent-reported physical activity and quality of life (QoL) relative to placebo. In a separate placebo-controlled trial of obese adults without known hypothalamic lesions, obese subjects who received long-acting octreotide lost weight and reduced their BMI compared to subjects receiving placebo; post hoc analysis suggested greater effects in patients receiving the higher dose of the drug, and among "Caucasian subjects having insulin secretion greater than the median of the cohort." "There were no statistically significant changes in QoL scores, body fat, leptin concentration, Beck Depression Inventory, or macronutrient intake", although subjects taking octreotide had higher blood glucose after a glucose tolerance test than those receiving placebo.
References
External links
"Octreotide". Drug Information Portal. U.S. National Library of Medicine.
"Octreotide acetate". Drug Information Portal. U.S. National Library of Medicine. |
Chlorothiazide | Chlorothiazide, sold under the brand name Diuril among others, is an organic compound used as a diuretic and as an antihypertensive.It is used both within the hospital setting or for personal use to manage excess fluid associated with congestive heart failure. Most often taken in pill form, it is usually taken orally once or twice a day. In the ICU setting, chlorothiazide is given to diurese a patient in addition to furosemide (Lasix). Working in a separate mechanism from furosemide and absorbed enterically as a reconstituted suspension administered through a nasogastric tube (NG tube), the two drugs potentiate one another.
It was patented in 1956 and approved for medical use in 1958. It is on the World Health Organizations List of Essential Medicines.
Indications
Large amount of excess fluid including:
Heart failure
Peripheral edema
Hypertension
Contraindications
Anuria
Allergies to sulfa drugs
Side effects
Nausea / Vomiting
Headache
Dizziness
Excess urine production
Dehydration
Hypoelectrolytemia (esp. hypokalemia / hypomagnesia)
History
The research team of Merck Sharp and Dohme Research Laboratories of Beyer, Sprague, Baer, and Novello created a new series of medications, the thiazide diuretics, which includes chlorothiazide. They won an Albert Lasker Special Award in 1975 for this work.The structure has been determined by X-ray crystallography.
See also
Hydrochlorothiazide
== References == |
Rifapentine | Rifapentine, sold under the brand name Priftin, is an antibiotic used in the treatment of tuberculosis. In active tuberculosis it is used together with other antituberculosis medications. In latent tuberculosis it is typically used with isoniazid. It is taken by mouth.Common side effects include low neutrophil counts in the blood, elevated liver enzymes, and white blood cells in the urine. Serious side effects may include liver problems or Clostridium difficile associated diarrhea. It is unclear if use during pregnancy is safe. Rifapentine is in the rifamycin family of medication and works by blocking DNA-dependent RNA polymerase.Rifapentine was approved for medical use in the United States in 1998. It is on the World Health Organizations List of Essential Medicines. In many areas of the world it is not easy to get as of 2015.
Medical uses
A systematic review of regimens for prevention of active tuberculosis in HIV-negative individuals with latent TB found that a weekly, directly observed regimen of rifapentine with isoniazid for three months was as effective as a daily, self-administered regimen of isoniazid for nine months. The three-month rifapentine-isoniazid regimen had higher rates of treatment completion and lower rates of hepatotoxicity. However, the rate of treatment-limiting adverse events was higher in the rifapentine-isoniazid regimen compared to the nine-month isoniazid regimen.
Pregnancy
Rifapentine has been assigned a pregnancy category C by the U.S. Food and Drug Administration (FDA). Rifapentine in pregnant women has not been studied, but animal reproduction studies have resulted in fetal harm and were teratogenic. If rifapentine or rifampin are used in late pregnancy, coagulation should be monitored due to a possible increased risk of maternal postpartum hemorrhage and infant bleeding.
Adverse effects
Common side effects include allergic reaction, anemia, neutropenia, elevated transaminases, and pyuria. Overdoses have been associated with hematuria and hyperuricemia.
Contraindications
Rifapentine should be avoided in patients with an allergy to the rifamycin class of drugs. This drug class includes rifampicin and rifabutin.
Interactions
Rifapentine induces metabolism by CYP3A4, CYP2C8 and CYP2C9 enzymes. It may be necessary to adjust the dosage of drugs metabolized by these enzymes if they are taken with rifapentine. Examples of drugs that may be affected by rifapentine include warfarin, propranolol, digoxin, protease inhibitors and birth control pills.
Chemical structure
The chemical structure of rifapentine is similar to that of rifamycin, with the notable substitution of a methyl group for a cyclopentane (C5H9) group.
History
Rifapentine was first synthesized in 1965, by the same company that produced rifampicin. The drug was approved by the U.S. Food and Drug Administration (FDA) in June 1998. It is made from rifampicin.Rifapentine was granted orphan drug designation by the FDA in June 1995, and by the European Commission in June 2010.
Society and culture
Cancer-causing impurities
In August 2020, the U.S. Food and Drug Administration (FDA) became aware of nitrosamine impurities in certain samples of rifapentine. The FDA and manufacturers are investigating the origin of these impurities in rifapentine, and the agency is developing testing methods for regulators and industry to detect the 1-cyclopentyl-4-nitrosopiperazine (CPNP). CPNP belongs to the nitrosamine class of compounds, some of which are classified as probable or possible human carcinogens (substances that could cause cancer), based on laboratory tests such as rodent carcinogenicity studies. Although there are no data available to directly evaluate the carcinogenic potential of CPNP, information available on closely related nitrosamine compounds was used to calculate lifetime exposure limits for CPNP.As of January 2021, the FDA continues to investigate the presence of 1-methyl-4-nitrosopiperazine (MNP) in rifampin or 1-cyclopentyl-4-nitrosopiperazine (CPNP) in rifapentine approved for sale in the US.
See also
Rifampicin
Isoniazid
Rifamycin
Rifabutin
References
External links
"Rifapentine". Drug Information Portal. U.S. National Library of Medicine. |
Clindamycin/benzoyl peroxide | Clindamycin/benzoyl peroxide is a topical gel used for the treatment of acne. It is a combination of clindamycin, an antibiotic, and benzoyl peroxide, an antiseptic.Common side effects include peeling, itching, and dryness of the skin where the gel was applied.Clindamycin/benzoyl peroxide was approved for medical use in the United States in December 2000. It is available as a generic medication.
Medical uses
The gel is used on the skin to treat light to medium acne vulgaris in people 12 years and older.
Efficacy
There is an average 52% decrease in inflammatory acne lesions by week 12.The combination is less effective than benzoyl peroxide/salicylic acid after short-term treatment of two to four weeks, but the two treatments showed similar effectiveness after ten to twelve weeks.
Pregnancy and lactation
Studies on whether or not the use of clindamycin/benzoyl peroxide gels is teratogenic or has adverse effects on nursing infants have not been performed. While oral clindamycin passes into breast milk, no such data are available for clindamyin in gel form. Limited data regarding topical clindamycin and benzoyl peroxide have shown no safety problems.
Contraindications
The gel is not recommended for those who are allergic to clindamycin, benzoyl peroxide, any components of the formulation, or lincomycin. Individuals previously diagnosed with regional enteritis, ulcerative colitis, or antibiotic-associated colitis are also recommended not to use it.
Side effects
Common side effects are peeling, itching, redness, dryness, burning, and dermatitis. Benzoyl peroxide bleaches hair, clothes, towels, bedclothing, and the like. Prolonged exposure to natural or artificial sun light (UV rays) is not recommended because the gel may cause photosensitivity. Irritation due to benzoyl peroxide can be reduced by avoiding harsh facial cleansers and wearing sunscreen prior to sun exposure.Clinical studies have shown systemic absorption of clindamycin through topical application, in some cases leading to diarrhea, bloody diarrhea, and colitis. Reports of anaphylaxis were also seen. However, the sources of these reports were personal accounts without controls and of an unknown population, thus it is difficult to attribute their cause to the clindamycin/benzoyl peroxide gel.
Interactions
No formal interaction studies have been done. Combination with topical products containing alcohol or astringents, as well as skin peelings, may increase the irritant effect of clindamycin/benzoyl peroxide. Topical erythromycin may antagonise the effect of clindamycin, although this has only be demonstrated in in vitro studies. Topical tretinoin and other retinoids may be inactivated by benzoyl peroxide or increase its irritant effect.
Pharmacology
Mechanism of action
Clindamycin phosphate is a water-soluble ester of the semi-synthetic antibiotic clindamycin, which is synthesized from lincomycin. Like the macrolide antibiotics, it acts as a bacteriostatic agent by interfering with the 50S subunit of the ribosome of Cutibacterium acnes, inhibiting bacterial protein synthesis and preventing bacteria from replicating. C. acnes plays a role in the development of acne.Benzoyl peroxide also kills C. acnes, but by releasing free radical oxygen species, thus oxidizing bacterial proteins. Also, it dries out the area by reducing sebum production, prevents clogged pores, and is a keratolytic agent. Since benzoyl peroxide is an oxidizer, not an antibiotic, it is not subject to C. acnes resistance unlike clindamycin.Both ingredients have been shown to reduce the number of acne lesions with statistical significance.
Pharmacokinetics
Clindamycin phosphate is an inactive prodrug. It is quickly activated to clindamycin by hydrolysis. After four weeks of application during a study, 0.043% of the used clindamycin dose were found in the blood. Benzoyl peroxide is only absorbed through the skin after reduction to benzoic acid, which is subsequently metabolized to hippuric acid and eliminated via the kidneys.
Society and culture
Brand names
The combination is sold under various brand names including Acanya, Benzaclin, Duac, and Onexton.
Patent
Dow Pharmaceuticals filed the patent for Onexton, and the United States Patent and Trademark Office issued the patent on 16 October 2012. On 24 November 2014, the US Food and Drug Administration (FDA) approved the new drug application (NDA) No. 050819 for Onexton, with Dow Pharmaceutical as the holder. The patent is set to expire on 5 August 2029.
Lawsuits
On 12 January 2016, Dow Pharmaceutical Sciences and Valeant Pharmaceuticals North America LLC filed a lawsuit against Taro USA and Taro Industries, an Israel-based corporation. The lawsuit was filed for infringement upon their Onexton patent, by Taro attempting to submit an abbreviated new drug application (ANDA) to the Food and Drug Administration (FDA) for its generic 3.75% benzoyl peroxide and 1.2% clindamycin phosphate topical gel. The court concluded that Taro was guilty of attempting to submit an ANDA patent request before the Onexton patent expired. Perrigo settled its patent litigation with Valeant and Dow.
References
External links
"Benzoyl peroxide mixture with clindamycin phosphate". Drug Information Portal. U.S. National Library of Medicine. |
Alendronic acid | Alendronic acid, sold under the brand name Fosamax among others, is a bisphosphonate medication used to treat osteoporosis and Pagets disease of bone. It is taken by mouth. Use is often recommended together with vitamin D, calcium supplementation, and lifestyle changes.Common side effects (1 to 10% of patients) include constipation, abdominal pain, nausea, and acid reflux. Use is not recommended during pregnancy or in those with poor kidney function. Alendronic acid works by decreasing the activity of cells that break down bone.Alendronic acid was first described in 1978 and approved for medical use in the United States in 1995. It is available as a generic medication. In 2019, it was the 96th most commonly prescribed medication in the United States, with more than 7 million prescriptions.
Medical uses
Prevention and treatment of female osteoporosis
Treatment of male osteoporosis
Prevention and treatment of corticosteroid-associated osteoporosis together with supplements of calcium and vitamin D
Pagets disease
Contraindications
Alendronate should not be used in:
Acute inflammations of the gastrointestinal tract (esophagitis, gastritis, ulcerations)
Clinically manifested osteomalacia
Certain malformations and malfunctions of the esophagus (strictures, achalasia)
Inability to stand, walk, or sit for 30 minutes after oral administration
Renal impairment or chronic kidney disease as evidenced by a creatinine clearance below 30ml/min
Hypersensitivity to alendronate or another ingredient in the product
Hypocalcemia
Pregnancy and breastfeeding
Patients below 18 yrs. of age, as no clinical data exists for this population
Side effects
Gastrointestinal tract:
Ulceration and possible rupture of the esophagus; this may require hospitalization and intensive treatment. Gastric and duodenal ulceration may also occur.
Esophageal cancer, a meta-analysis concluded that bisphosphonate treatment is NOT associated with excess risk of esophageal cancer.
General: infrequent cases of skin rash, rarely manifesting as Stevens–Johnson syndrome and toxic epidermal necrolysis, eye problems (uveitis, scleritis) and generalized muscle, joint, and bone pain (rarely severe) have been reported. In laboratory tests, decreased calcium and phosphate values may be seen but reflect expected action of the drug and are almost always not clinically relevant.
Osteonecrosis of the jaw may occur while on this drug, if dental work of any kind is carried out. The risk is considerably higher for extractions in the mandible (lower jaw) than other areas of the mouth, and the risk increases if you have been taking it for four or more years Although this side effect is uncommon (0.4-1.6% for oral alendronic acid), it occurs primarily in patients being administered intravenous bisphosphonates, with most cases being reported in cancer patients.
Bone: alendronate has been linked in long-term users to the development of low-impact femoral fractures. Further, studies suggest that users of alendronate have an increase in the numbers of osteoclasts and develop giant, more multinucleated osteoclasts; the significance of this development is unclear. Fosamax has been linked to a rare type of leg fracture that cuts straight across the upper thigh bone after little or no trauma (subtrochanteric fractures).
Interactions
Food and drugs containing large amounts of calcium, magnesium or aluminium (antacids) decrease the absorption of alendronate. At least half an hour should pass after intake of alendronate before eating dairy products or taking the supplement or drug.
Highly active vitamin D analogues or fluorides: no data is available. Concomitant treatment should be avoided.
The additional beneficial effect of HRT (hormone replacement therapy) with estrogens/progestins or raloxifene in postmenopausal women with osteoporosis remains to be elucidated, but no interactions have been seen. The combination is therefore possible, but controversial.
Intravenous ranitidine increases the oral bioavailability of alendronate. No clinical consequences are known.
The combination of NSAIDs and alendronate may increase the risk of gastric ulcers. Both these drugs have the potential to irritate the upper gastro-intestinal mucosa.
Pharmacology
Mechanism of action
Alendronate inhibits osteoclast-mediated bone-resorption. Like all bisphosphonates, it is chemically related to inorganic pyrophosphate, the endogenous regulator of bone turnover. But while pyrophosphate inhibits both osteoclastic bone resorption and the mineralization of the bone newly formed by osteoblasts, alendronate specifically inhibits bone resorption without any effect on mineralization at pharmacologically achievable doses. Its inhibition of bone-resorption is dose-dependent and approximately 1,000 times stronger than the equimolar effect of the first bisphosphonate drug, etidronate. Under therapy, normal bone tissue develops, and alendronate is deposited in the bone-matrix in a pharmacologically inactive form. For optimal action, enough calcium and vitamin D are needed in the body in order to promote normal bone development. Hypocalcemia should, therefore, be corrected before starting therapy.
Etidronate has the same disadvantage as pyrophosphate in inhibiting mineralization, but all of the potent N-containing bisphosphonates, including alendronate, risedronate, ibandronate, and zoledronate, do not.
Pharmacokinetics
As with all potent bisphosphonates, the fraction of the drug that reaches the circulatory system intact (systemic bioavailability) after oral dosing is low, averaging only 0.6–0.7% in women and in men under fasting conditions. Intake together with meals and beverages other than water further reduces the bioavailability. The absorbed drug rapidly partitions, with approximately 50% binding to the exposed bone surface; the remainder is excreted unchanged by the kidneys. Unlike with most drugs, the strong negative charge on the two phosphonate moieties limits oral bioavailability, and, in turn, the exposure to tissues other than bone is very low. After absorption in the bone, alendronate has an estimated terminal elimination half-life of 10 years.
References
External links
"Alendronic acid". Drug Information Portal. U.S. National Library of Medicine.
"Alendronate sodium". Drug Information Portal. U.S. National Library of Medicine. |
Pseudoephedrine/loratadine | Pseudoephedrine/loratadine (trade names Claritin-D, Clarinase, Clarinase Repetabs, Lorinase, Rhinos SR, Allerclear-D) is an orally administered combination drug used for the treatment of allergic rhinitis and the common cold. This drug can be bought "over the counter" in some countries (United States, Hong Kong), but it is restricted to prescription in others (Czech Republic, Israel).
Pseudoephedrine, one of the naturally occurring alkaloids of ephedra, is a sympathomimetic used as a decongestant. It produces a decongestant effect that is facilitated by the vasoconstriction in the mucosal capillaries of the upper respiratory areas.
Loratadine is a long-acting antihistamine (H1 histamine antagonist) that is less sedating than older substances of its type.
Medical uses
Pseudoephedrine/loratadine are indicated for the relief of symptoms associated with allergic rhinitis and the common cold including nasal congestion, sneezing, rhinorrhea, pruritus and lacrimation.
Composition
Clarinase Repetabs
A Clarinase Repetab tablet contains 5 mg loratadine in the tablet coating and 120 mg pseudoephedrine sulfate equally distributed between the tablet coating and the barrier-coated core. The two active components in the coating are quickly liberated; release of pseudoephedrine in the core is delayed for several hours.
Interactions, adverse effects and contraindications
Interactions, adverse effects and contraindications are described in more detail in the articles about pseudoephedrine and loratadine.
Interactions
When sympathomimetics are given to patients receiving monoamine oxidase inhibitors (MAO inhibitors), hypertensive reactions, including hypertensive crises may occur.
Adverse effects
During controlled clinical studies with the recommended dosage, the incidence of adverse effects was comparable to that of placebo, with the exception of insomnia and dry mouth, both of which were commonly reported.
Contraindications
Clarinase is contraindicated in patients receiving MAO inhibitor therapy or within 14 days of discontinuing such treatment and in patients with narrow angle glaucoma, urinary retention, severe hypertension, severe coronary artery disease and hyperthyroidism.
References
Drugs.com: Claritin-D
Israel Ministry of Health: Clarinase Repetabs
Haberfeld H, ed. (2009). Austria-Codex (in German) (2009/2010 ed.). Vienna: Österreichischer Apothekerverlag. Clarinase 5 mg/120 mg Retardtabletten. ISBN 978-3-85200-196-8. |
Aspirin/paracetamol/caffeine | Aspirin/paracetamol(acetaminophen)/caffeine is a combination drug for the treatment of pain, especially tension headache and migraine. It is sold in the US under the trade names Goodys Powder and Excedrin, although not all products sold under the Excedrin brand contain this combination. It is sold in the UK under various brandnames including Anadin Extra.
Adverse effects
The recommended dosing has a low risk profile when taken occasionally in a well hydrated state. As with all medications containing paracetamol (acetaminophen), concomitant use with alcohol carries a significant risk of hepatotoxicity. The combination of paracetamol with aspirin also creates the risk of renal papillary necrosis if large doses are taken chronically. This is because paracetamol yields a toxic metabolite that can accumulate in the kidney while aspirin works to deplete the glutathione stores necessary to oxidize it. Additionally, chronic aspirin usage is associated with increased risk of gastrointestinal bleeding.
Chemical detection
The combination of these three compounds can be detected in pharmaceutical formulations, urine and blood serum in trace quantities using electrochemical methods.
Other trade names
The combination was introduced in 1950, sold as the name Triagesic. It has been famous in 1964, under the trade name Vanquish by Sterling Drug, which after a series of mergers and acquisitions became a unit of Bayer AG.In Germany, it is sold as dolomo, Dolopyrin AL, HA-Tabletten, Melabon K, Neuralgin, ratiopyrin, Thomapyrin Classic, Thomapyrin Intensiv, in Austria as Thomapyrin, and InfluASS, in Israel as Acamol Focus, Paramol Target and Exidol, in Romania as Antinevralgic P and Antinevralgic Forte, and in Russia, Belarus and Eastern Europe as Citramon.
== References == |
Famotidine | Famotidine, sold under the brand name Pepcid among others, is a histamine H2 receptor antagonist medication that decreases stomach acid production. It is used to treat peptic ulcer disease, gastroesophageal reflux disease, and Zollinger-Ellison syndrome. It is taken by mouth or by injection into a vein. It begins working within an hour.Common side effects include headache, intestinal upset, and dizziness. Serious side effects may include pneumonia and seizures. Use in pregnancy appears safe but has not been well studied while use during breastfeeding is not recommended.Famotidine was patented in 1979 and came into medical use in 1985. It is available as a generic medication. In 2019, it was the 104th most commonly prescribed medication in the United States, with more than 6 million prescriptions.
Medical uses
Relief of heartburn, acid indigestion, and sour stomach
Treatment for gastric and duodenal ulcers
Treatment for pathologic gastrointestinal hypersecretory conditions such as Zollinger–Ellison syndrome and multiple endocrine adenomas
Treatment for gastroesophageal reflux disease (GERD)
Treatment for esophagitis
Part of a multidrug regimen for Helicobacter pylori eradication, although omeprazole may be somewhat more effective.
Prevention of NSAID-induced peptic ulcers.
Given to surgery patients before operations to reduce the risk of aspiration pneumonitis.
Pharmacokinetics
Famotidine has a delayed onset of action, beginning after 90 minutes. However, famotidine has a duration of effect of at least 540 minutes (9.0 h). At its peak effect, 210 minutes (3.5 h) after administration, famotidine reduces acid secretion by 7.3 mmol per 30 minutes.
Side effects
The most common side effects associated with famotidine use include headache, dizziness, and constipation or diarrhea.Famotidine may contribute to QT prolongation, particularly when used with other QT-elongating drugs, or in people with poor kidney function.
Mechanism of action
Activation of H2 receptors located on parietal cells stimulates proton pumps to secrete acid into the stomach lumen. Famotidine, an H2 antagonist, blocks the action of histamine on the parietal cells, ultimately reducing acid secretion into the stomach.
Interactions
Unlike cimetidine, the first H2 antagonist, famotidine has a minimal effect on the cytochrome P450 enzyme system, and does not appear to interact with as many drugs as other medications in its class. Some exceptions include antiretrovirals such as atazanavir, chemotherapeutics such as doxorubicin, and antifungal medications such as itraconazole.
History
Famotidine was developed by Yamanouchi Pharmaceutical Co. It was licensed in the mid-1980s by Merck & Co. and is marketed by a joint venture between Merck and Johnson & Johnson. The imidazole ring of cimetidine was replaced with a 2-guanidinothiazole ring. Famotidine proved to be nine times more potent than ranitidine, and thirty-two times more potent than cimetidine.It was first marketed in 1981. Pepcid RPD orally disintegrating tablets were released in 1999. Generic preparations became available in 2001, e.g. Fluxid (Schwarz) or Quamatel (Gedeon Richter Ltd.).
In the United States and Canada, a product called Pepcid Complete, which combines famotidine with an antacid in a chewable tablet to quickly relieve the symptoms of excess stomach acid, is available. In the UK, this product was known as PepcidTwo until its discontinuation in April 2015.Famotidine has poor bioavailibility (50%) due to low gastroretention time. Famotidine is less soluble at higher pH, and when used in combination with antacids gastroretention time is increased. This promotes local delivery of these drugs to receptors in the parietal cell membrane and increases bioavailibility. Researchers are developing tablet formulations that rely on other gastroretentive drug delivery systems such as floating tablets to further increase bioavailibility.
Society and culture
Certain preparations of famotidine are available over the counter (OTC) in various countries. In the United States and Canada, 10 mg and 20 mg tablets, sometimes in combination with an antacid, are available OTC. Larger doses still require a medical prescription.
Formulations of famotidine in combination with ibuprofen were marketed by Horizon Pharma under the trade name Duexis.
Research
COVID-19
At the start of the COVID-19 pandemic, some doctors observed that anecdotally some hospitalized patients on famotidine in China may have had better outcomes that other patients that were not taking famotidine. This lead to hypotheses about use of famotidine in treament of COVID-19. Famotidine was researched for potential benefit in treating COVID-19 following hypotheses at the start of the pandemic that it may be an applicable medication. No good evidence of benefit was found.
Veterinary uses
Famotidine is given to dogs and cats with acid reflux. Famotidine has been used in combination with an H1 antagonist to treat and prevent urticaria caused by an acute allergic reaction.
References
External links
"Famotidine". Drug Information Portal. U.S. National Library of Medicine. |
Tegaserod | Tegaserod is a 5-HT4 agonist manufactured by Novartis and sold under the names Zelnorm and Zelmac for the management of irritable bowel syndrome and constipation. Approved by the FDA in 2002, it was subsequently removed from the market in 2007 due to FDA concerns about possible adverse cardiovascular effects. Before then, it was the only drug approved by the United States Food and Drug Administration to help relieve the abdominal discomfort, bloating, and constipation associated with irritable bowel syndrome. Its use was also approved to treat chronic idiopathic constipation.
Mechanism of action
The drug functions as a motility stimulant, achieving its desired therapeutic effects through activation of the 5-HT4 receptors of the enteric nervous system in the gastrointestinal tract. It also stimulates gastrointestinal motility and the peristaltic reflex, and allegedly reduces abdominal pain. Additionally, tegaserod is a 5-HT2B receptor antagonist.
Withdrawal from market
On 30 March 2007, the United States Food and Drug Administration requested that Novartis withdraw tegaserod from shelves. The FDA alleged a relationship between prescriptions of the drug and increased risks of heart attack or stroke. An analysis of data collected on over 18,000 patients demonstrated adverse cardiovascular events in 13 of 11,614 patients treated with tegaserod (a rate of 0.11%) as compared with 1 of 7,031 patients treated with placebo (a rate of 0.01%). Novartis alleged all of the affected patients had preexisting cardiovascular disease or risk factors for such, and further alleged that no causal relationship between tegaserod use and cardiovascular events has been demonstrated.
On the same day as the FDA announcement, Novartis Pharmaceuticals Canada announced that it was suspending marketing and sales of the drug in Canada in response to a request from Health Canada. In a large cohort study based on a US health insurance database, no increase in the risk of cardiovascular events were found under tegaserod treatment. In 2019, tegaserod was reintroduced as for use in irritable bowel syndrome with constipation (IBS-C) in women under 65.
== References == |
Dofetilide | Dofetilide is a class III antiarrhythmic agent. It is marketed under the trade name Tikosyn by Pfizer, and is available in the United States in capsules containing 125, 250, and 500 µg of dofetilide. It is not available in Europe or Australia. In the United States it is only available by mail order or through specially trained local pharmacies.
Medical uses
Dofetilide is used for the maintenance of sinus rhythm in individuals prone to the occurrence of atrial fibrillation and flutter arrhythmias, and for chemical cardioversion to sinus rhythm from atrial fibrillation and flutter.Based on the results of the Danish Investigations of Arrhythmias and Mortality on Dofetilide ("DIAMOND") study, dofetilide does not affect mortality in the treatment of patients post-myocardial infarction with left ventricular dysfunction, however it was shown to decrease all-cause readmissions as well as CHF-related readmissions. Because of the results of the DIAMOND study, some physicians use dofetilide in the suppression of atrial fibrillation in individuals with LV dysfunction, however use appears limited: After initially receiving marketing approval in Europe in 1999, Pfizer voluntarily withdrew this approval in 2004 for commercial reasons and it is not registered in other first world countries.
It has clinical advantages over other class III antiarrhythmics in chemical cardioversion of atrial fibrillation, and maintenance of sinus rhythm, and does not have the pulmonary or hepatotoxicity of amiodarone, however atrial fibrillation is not generally considered life-threatening, and dofetilide causes an increased rate of potentially life-threatening arrhythmias in comparison to other therapies.
Contraindications
Prior to administration of the first dose, the corrected QT (QTc) must be determined. If the QTc is greater than 440 msec (or 500 msec in patients with ventricular conduction abnormalities), dofetilide is contraindicated. If heart rate is less than 60 bpm, the uncorrected QT interval should be used. After each subsequent dose of dofetilide, QTc should be determined and dosing should be adjusted. If at any time after the second dose of dofetilide the QTc is greater than 500 msec (550 msec in patients with ventricular conduction abnormalities), dofetilide should be discontinued.
Adverse effects
Torsades de pointes is the most serious side effect of dofetilide therapy. The incidence of torsades de pointes is 0.3-10.5% and is dose-related, with increased incidence associated with higher doses. The majority of episodes of torsades de pointes have occurred within the first three days of initial dosing. Patients should be hospitalized and monitored for the first three days after starting dofetilide.The risk of inducing torsades de pointes can be decreased by taking precautions when initiating therapy, such as hospitalizing individuals for a minimum of three days for serial creatinine measurement, continuous telemetry monitoring and availability of cardiac resuscitation.
Pharmacology
Mechanism of action
Dofetilide works by selectively blocking the rapid component of the delayed rectifier outward potassium current (IKr).This causes the refractory period of atrial tissue to increase, hence its effectiveness in the treatment of atrial fibrillation and atrial flutter.
Dofetilide does not affect dV/dTmax (the slope of the upstroke of phase 0 depolarization), conduction velocity, or the resting membrane potential.
There is a dose-dependent increase in the QT interval and the corrected QT interval (QTc). Because of this, many practitioners will initiate dofetilide therapy only on individuals under telemetry monitoring or if serial EKG measurements of QT and QTc can be performed.
Pharmacokinetics
Peak plasma concentrations are seen two to three hours after oral dosing when fasting. Dofetilide is well absorbed in its oral form, with a bioavailability of >90%. Intravenous administration of dofetilide is not available in the United States. The elimination half-life of dofetilide is roughly 10 hours; however, this varies based on many physiologic factors (most significantly creatinine clearance), and ranges from 4.8 to 13.5 hours. Due to the significant level of renal elimination (80% unchanged, 20% metabolites), the dose of dofetilide must be adjusted to prevent toxicity due to impaired renal function.Dofetilide is metabolized predominantly by CYP3A4 enzymes predominantly in the liver and GI tract. This means that it is likely to interact with drugs that inhibit CYP3A4, such as erythromycin, clarithromycin, or ketoconazole, resulting in higher and potentially toxic levels of dofetilide.
Metabolism
A steady-state plasma level of dofetilide is achieved in 2–3 days.
80% of dofetilide is excreted by the kidneys, so the dose of dofetilide should be adjusted in individuals with chronic kidney disease, based on creatinine clearance.
In the kidneys, dofetilide is eliminated via cation exchange (secretion). Agents that interfere with the renal cation exchange system, such as verapamil, cimetidine, hydrochlorothiazide, itraconazole, ketoconazole, prochlorperazine, and trimethoprim should not be administered to individuals taking dofetilide.
About 20 percent of dofetilide is metabolized in the liver via the CYP3A4 isoenzyme of the cytochrome P450 enzyme system. Drugs that interfere with the activity of the CYP3A4 isoenzyme can increase serum dofetilide levels. If the renal cation exchange system is interfered with (as with the medications listed above), a larger percentage of dofetilide is cleared via the CYP3A4 isoenzyme system.
History
After its initial US FDA approval, due to the pro-arrhythmic potential it was only made available to hospitals and prescribers that had received education and undergone specific training in the risks of treatment with dofetilide; however, this restriction was subsequently removed in 2016.
See also
Antiarrhythmic agents
Cardiac action potential
Electrocardiogram
== References == |
Zinc acetate | Zinc acetate is a salt with the formula Zn(CH3CO2)2, which commonly occurs as the dihydrate Zn(CH3CO2)2·2H2O. Both the hydrate and the anhydrous forms are colorless solids that are used as dietary supplements. When used as a food additive, it has the E number E650.
Uses
Zinc acetate is a component of some medicines, e.g., lozenges for treating the common cold. Zinc acetate can also be used as a dietary supplement. As an oral daily supplement it is used to inhibit the bodys absorption of copper as part of the treatment for Wilsons disease. Zinc acetate is also sold as an astringent in the form of an ointment, a topical lotion, or combined with an antibiotic such as erythromycin for the topical treatment of acne. It is commonly sold as a topical anti-itch ointment.
Zinc acetate is used as the catalyst for the industrial production of vinyl acetate from acetylene:
Approximately 1/3 of the worlds production uses this route, which because it is environmentally messy, is mainly practiced in countries with relaxed environmental regulations such as China.
Preparation
Zinc acetates are prepared by the action of acetic acid on zinc carbonate or zinc metal. Treatment of zinc nitrate with acetic anhydride is an alternative route.
Structures
In anhydrous zinc acetate the zinc is coordinated to four oxygen atoms to give a tetrahedral environment, these tetrahedral polyhedra are then interconnected by acetate ligands to give a range of polymeric structures.In the dihydrate, zinc is octahedral, wherein both acetate groups are bidentate.
Reactions
Heating Zn(CH3CO2)2 in a vacuum results in a loss of acetic anhydride, leaving a residue of "basic zinc acetate," with the formula Zn4O(CH3CO2)6. It can also be prepared by a reaction of glacial acetic acid with zinc oxide. The cluster compound has a tetrahedral structure with an oxide ligand at its center Basic zinc acetate is a common precursor to metal-organic frameworks (MOFs).
See also
Basic beryllium acetate - isostructural with basic zinc acetate
== References == |
Bicalutamide | Bicalutamide, sold under the brand name Casodex among others, is an antiandrogen medication that is primarily used to treat prostate cancer. It is typically used together with a gonadotropin-releasing hormone (GnRH) analogue or surgical removal of the testicles to treat advanced prostate cancer. To a lesser extent, it is used for early prostate cancer at a higher dosage as a monotherapy without castration. Bicalutamide is also used to treat excessive hair growth and scalp hair loss in women, as a component of feminizing hormone therapy for transgender women, to treat early puberty in boys, and to prevent overly long-lasting erections in men. It is taken by mouth.Common side effects in men include breast enlargement, breast tenderness, and hot flashes. Other side effects in men include feminization and sexual dysfunction. Some side effects like breast changes and feminization are minimal when combined with castration. While the medication appears to produce few side effects in women, its use in cisgender women is not recommended by the Food and Drug Administration (FDA) at this time. Use during pregnancy may harm the baby. Bicalutamide causes abnormal liver changes necessitating discontinuation in around 1% of people. Rarely, it has been associated with cases of liver damage, lung toxicity, and sensitivity to light. Although the risk of adverse liver changes is small, monitoring of liver function is recommended during treatment.Bicalutamide is a member of the nonsteroidal antiandrogen (NSAA) group of medications. It works by selectively blocking the androgen receptor (AR), the biological target of the androgen sex hormones testosterone and dihydrotestosterone (DHT). It does not lower androgen levels. The medication can have some estrogen-like effects in men when used as a monotherapy due to increased estradiol levels. Bicalutamide is well-absorbed, and its absorption is not affected by food. The elimination half-life of the medication is around one week. It shows peripheral selectivity in animals, but crosses the blood–brain barrier and affects both the body and brain in humans.Bicalutamide was patented in 1982 and approved for medical use in 1995. It is on the World Health Organizations List of Essential Medicines. Bicalutamide is available as a generic medication. The drug is sold in more than 80 countries, including most developed countries. It is the most widely used antiandrogen in the treatment of prostate cancer, and has been prescribed to millions of men with the disease.
Medical uses
Bicalutamide is approved for and mainly used in the following indications:
Metastatic prostate cancer (mPC) in men in combination with a gonadotropin-releasing hormone (GnRH) analogue or surgical castration at 50 mg/day
Locally advanced prostate cancer (LAPC) in men as a monotherapy at 150 mg/day (not approved for this use in the United States)In Japan, bicalutamide is uniquely used at a dosage of 80 mg/day both in combination with castration and as a monotherapy in the treatment of prostate cancer.Bicalutamide is also employed for the following off-label (non-approved) indications:
To reduce the effects of the testosterone flare at the initiation of GnRH agonist therapy in men
Androgen-dependent skin and hair conditions such as acne, seborrhea, excessive hair growth, and scalp hair loss in women as well as high testosterone levels due to polycystic ovary syndrome (PCOS) in women, at 25 to 50 mg/day generally in combination with a birth control pill
Feminizing hormone therapy for transgender women in combination with an estrogen usually at 50 mg/day
Peripheral precocious puberty in boys at 12.5 to 100 mg/day in combination with an aromatase inhibitor like anastrozole, especially for familial male-limited precocious puberty (testotoxicosis)
Overly long-lasting erections in men at 50 mg per week to 50 mg every other dayThe medication has been suggested for but has uncertain effectiveness in the following indication:
Hypersexuality and paraphilias, particularly in combination with chemical castrationFor more information on these uses, see the medical uses of bicalutamide article.
Available forms
Bicalutamide is available for the treatment of prostate cancer in most developed countries, including over 80 countries worldwide. It is available in 50 mg, 80 mg (in Japan), and 150 mg tablets for oral administration. The drug is registered for use as a 150 mg/day monotherapy for the treatment of LAPC in at least 55 countries, with the U.S. being a notable exception where it is registered only for use at a dosage of 50 mg/day in combination with castration. No other formulations or routes of administration are available or used. All formulations of bicalutamide are specifically indicated for the treatment of prostate cancer alone or in combination with surgical or medication castration. A combined formulation of bicalutamide and the GnRH agonist goserelin in which goserelin is provided as a subcutaneous implant for injection and bicalutamide is included as 50 mg tablets for oral ingestion is marketed in Australia and New Zealand under the brand name ZolaCos CP (Zoladex–Cosudex Combination Pack).
Contraindications
Bicalutamide is pregnancy category X, or "contraindicated in pregnancy", in the U.S., and pregnancy category D, the second most restricted rating, in Australia. As such, it is contraindicated in women during pregnancy, and women who are sexually active and who can or may become pregnant are strongly recommended to take bicalutamide only in combination with adequate contraception. It is unknown whether bicalutamide is excreted in breast milk, but many drugs are excreted in breast milk, and for this reason, bicalutamide treatment is similarly not recommended while breastfeeding.In individuals with severe, though not mild-to-moderate hepatic impairment, there is evidence that the elimination of bicalutamide is slowed, and hence, caution may be warranted in these patients as circulating levels of bicalutamide may be increased. In severe hepatic impairment, the elimination half-life of the active (R)-enantiomer of bicalutamide is increased by about 1.75-fold (76% increase; elimination half-life of 5.9 and 10.4 days for normal and impaired patients, respectively). The elimination half-life of bicalutamide is unchanged in renal impairment.
Side effects
The side effect profile of bicalutamide is highly dependent on sex; that is, on whether the person is male or female. In men, due to androgen deprivation, a variety of side effects of varying severity may occur during bicalutamide treatment, with breast pain/tenderness and gynecomastia (breast development/enlargement) being the most common. Gynecomastia occurs in up to 80% of men treated with bicalutamide monotherapy, though is of only mild-to-moderate severity in more than 90% of affected men. In addition to breast changes, physical feminization and demasculinization in general, including reduced body hair growth, decreased muscle mass and strength, feminine changes in fat mass and distribution, reduced penile length, and decreased semen/ejaculate volume, may occur in men. Other side effects that have been observed in men and that are similarly related to androgen deprivation include hot flashes, sexual dysfunction (e.g., loss of libido, erectile dysfunction), depression, fatigue, weakness, and anemia. However, most men have preserved sexual function with bicalutamide monotherapy. In females, due to the minimal biological importance of androgens in this sex, the side effects of pure antiandrogens or NSAAs are few, and bicalutamide has been found to be very well tolerated. General side effects of bicalutamide that may occur in either sex include diarrhea, constipation, abdominal pain, nausea, dry skin, itching, and rash. The drug is well-tolerated at higher dosages than 50 mg/day, with rare additional side effects.Bicalutamide has been associated with abnormal liver function tests such as elevated liver enzymes. In the Early Prostate Cancer (EPC) clinical programme of bicalutamide for early prostate cancer, the rate of abnormal liver function tests with bicalutamide monotherapy was 3.4% relative to 1.9% for placebo. Hepatic changes that have necessitated discontinuation of bicalutamide, such as marked increases in liver enzymes or hepatitis, have occurred in approximately 0.3 to 1.4% of men in clinical trials. Elevated liver enzymes with bicalutamide usually occur within the first 3 to 6 months of treatment. Monitoring of liver function during treatment is recommended, particularly in the first few months. In men of advanced age with prostate cancer, bicalutamide monotherapy has been associated with an increase in non-prostate cancer mortality, in part due to an increase in the rate of heart failure. These mortality-related effects are thought to be a consequence of androgen deprivation, rather than due to a specific drug-related toxicity of bicalutamide.There are 10 published case reports of liver toxicity associated with bicalutamide as of 2021. Death occurred in 2 of these cases. In all reported cases, the onset of toxicity was within the first 6 months of treatment. Symptoms that may indicate liver dysfunction include nausea, vomiting, abdominal pain, fatigue, anorexia, "flu-like" symptoms, dark urine, and jaundice. There are also published case reports of interstitial pneumonitis and eosinophilic lung disease associated with bicalutamide. Interstitial pneumonitis can potentially progress to pulmonary fibrosis and may be fatal. Symptoms that may indicate lung dysfunction include dyspnea (difficult breathing or shortness of breath), cough, and pharyngitis (inflammation of the pharynx, resulting in sore throat). Both hepatotoxicity and interstitial pneumonitis are said to be very rare events with bicalutamide. A few cases of photosensitivity have been reported with bicalutamide. Hypersensitivity reactions (drug allergy) like angioedema and hives have also uncommonly been reported in association with bicalutamide.Because it is an antiandrogen, bicalutamide has a theoretical risk of birth defects like ambiguous genitalia and brain feminization in male fetuses. Due to its teratogenic capacity, contraception should be used in women taking bicalutamide who are fertile and sexually active.
Comparison
The side effect profile of bicalutamide in men and women differs from that of other antiandrogens and is considered favorable in comparison. Relative to GnRH analogues and the steroidal antiandrogen (SAA) cyproterone acetate (CPA), bicalutamide monotherapy has a much lower incidence and severity of hot flashes and sexual dysfunction. In addition, unlike GnRH analogues and CPA, bicalutamide monotherapy is not associated with decreased bone mineral density or osteoporosis. Conversely, bicalutamide monotherapy is associated with much higher rates of breast tenderness, gynecomastia, and feminization in men than GnRH analogues and CPA. However, gynecomastia with bicalutamide is rarely severe and discontinuation rates due to this side effect are fairly low. These differences in side effects between bicalutamide monotherapy, GnRH analogues, and CPA are attributed to the fact that whereas GnRH analogues and CPA suppress estrogen production, bicalutamide monotherapy does not lower estrogen levels and in fact actually increases them.Bicalutamide does not share the risk of neuropsychiatric side effects like depression and fatigue as well as cardiovascular side effects like coagulation changes, blood clots, fluid retention, ischemic cardiomyopathy, and adverse serum lipid changes that CPA has been associated with. It has a much lower risk of hepatotoxicity than flutamide and CPA and of interstitial pneumonitis than nilutamide. The drug also does not share the unique risks of diarrhea with flutamide and nausea, vomiting, visual disturbances, and alcohol intolerance with nilutamide. Unlike enzalutamide, bicalutamide is not associated with seizures or related central side effects like anxiety and insomnia. However, although the risk of adverse liver changes with bicalutamide is low, enzalutamide differs from bicalutamide in having no known risk of elevated liver enzymes or hepatotoxicity. In contrast to the SAA spironolactone, bicalutamide does not have antimineralocorticoid effects, and hence is not associated with hyperkalemia, urinary frequency, dehydration, hypotension, or other related side effects. In women, unlike CPA and spironolactone, bicalutamide does not produce menstrual irregularity or amenorrhea and does not interfere with ovulation or fertility.
Overdose
A single oral dose of bicalutamide in humans that results in symptoms of overdose or that is considered to be life-threatening has not been established. Dosages of up to 600 mg/day have been well tolerated in clinical trials, and it is notable that there is a saturation of absorption with bicalutamide such that circulating levels of its active (R)-enantiomer do not further increase above a dosage of 300 mg/day. Overdose is considered unlikely to be life-threatening with bicalutamide or other first-generation NSAAs (i.e., flutamide and nilutamide). A massive overdose of nilutamide (13 grams, or 43 times the normal maximum 300 mg/day clinical dosage) in a 79-year-old man was uneventful, producing no clinical signs, symptoms, or toxicity. There is no specific antidote for bicalutamide or NSAA overdose, and treatment should be based on symptoms, if any are present.
Interactions
Bicalutamide is almost exclusively metabolized by CYP3A4. As such, its levels in the body may be altered by inhibitors and inducers of CYP3A4. (For a list of CYP3A4 inhibitors and inducers, see here.) However, in spite of the fact bicalutamide is metabolized by CYP3A4, there is no evidence of clinically significant drug interactions when bicalutamide at a dosage of 150 mg/day or less is co-administered with drugs that inhibit or induce cytochrome P450 enzyme activity.In-vitro studies suggest that bicalutamide may be able to inhibit CYP3A4 and, to a lesser extent, CYP2C9, CYP2C19, and CYP2D6. Conversely, animal studies suggest that bicalutamide may induce cytochrome P450 enzymes. In a clinical study, bicalutamide co-administered with the CYP3A4 substrate midazolam caused only a small and statistically non-significant increase in midazolam levels (+27%) presumably due to CYP3A4 inhibition. However, this was well below the increases with potent CYP3A4 inhibitors like ketoconazole (+1500%), itraconazole (+1000%), and erythromycin (+350%), and is considered to not be clinically important. There is no indication of clinically significant enzyme inhibition or induction with bicalutamide at doses of 150 mg/day or below.Because bicalutamide circulates at relatively high concentrations and is highly protein-bound, it has the potential to displace other highly protein-bound drugs like warfarin, phenytoin, theophylline, and aspirin from plasma binding proteins. This could, in turn, result in increased free concentrations of such drugs and increased effects and/or side effects, potentially necessitating dosage adjustments. Bicalutamide has specifically been found to displace coumarin anticoagulants like warfarin from their plasma binding proteins (namely albumin) in vitro, potentially resulting in an increased anticoagulant effect, and for this reason, close monitoring of prothrombin time and dosage adjustment as necessary is recommended when bicalutamide is used in combination with these drugs. However, in spite of this, no conclusive evidence of an interaction between bicalutamide and other drugs was found in clinical trials of nearly 3,000 patients.
Pharmacology
Pharmacodynamics
Antiandrogenic activity
Bicalutamide acts as a highly selective competitive silent antagonist of the AR (IC50 = 159–243 nM), the major biological target of the androgen sex hormones testosterone and DHT, and hence is an antiandrogen. The activity of bicalutamide lies in the (R)-isomer. Due to its selectivity for the AR, bicalutamide does not interact importantly with other steroid hormone receptors and hence has no clinically relevant off-target hormonal activity (e.g., progestogenic, estrogenic, glucocorticoid, antimineralocorticoid). However, it has been reported that bicalutamide has weak affinity for the progesterone receptor (PR), where it is an antagonist, and hence it could have some antiprogestogenic activity. Bicalutamide does not inhibit 5α-reductase nor is known to inhibit other enzymes involved in androgen steroidogenesis (e.g., CYP17A1). Although it does not bind to the estrogen receptors (ERs), bicalutamide can increase estrogen levels secondarily to AR blockade when used as a monotherapy in males, and hence can have some indirect estrogenic effects in males. Bicalutamide neither suppresses nor inhibits androgen production in the body (i.e., it does not act as an antigonadotropin or androgen steroidogenesis inhibitor or lower androgen levels) and hence exclusively mediates its antiandrogenic effects by antagonizing the AR. In addition to the classical nuclear AR, bicalutamide has been assessed at the membrane androgen receptors (mARs) and found to act as a potent antagonist of ZIP9 (IC50 = 66.3 nM), whereas it does not appear to interact with GPRC6A.The affinity of bicalutamide for the AR is relatively low as it is approximately 30 to 100 times lower than that of DHT, which is 2.5- to 10-fold as potent as an AR agonist as testosterone in bioassays and is the main endogenous ligand of the receptor in the prostate gland. However, typical clinical dosages of bicalutamide result in circulating levels of the drug that are thousands of times higher than those of testosterone and DHT, allowing it to powerfully prevent them from binding to and activating the receptor. This is especially true in the case of surgical or medical castration, in which testosterone levels in the circulation are approximately 95% reduced and DHT levels in the prostate gland are about 50 to 60% reduced. In women, levels of testosterone are substantially lower (20- to 40-fold) than in men, so much smaller doses of bicalutamide (e.g., 25 mg/day in the hirsutism studies) are necessary.Blockade of the AR by bicalutamide in the pituitary gland and hypothalamus results in prevention of the negative feedback of androgens on the hypothalamic–pituitary–gonadal axis (HPG axis) in males and consequent disinhibition of pituitary luteinizing hormone (LH) secretion. This, in turn, results in an increase in circulating LH levels and activation of the gonadal production of testosterone and by extension production of estradiol. Levels of testosterone have been found to increase 1.5- to 2-fold (59–97% increase) and levels of estradiol about 1.5- to 2.5-fold (65–146% increase) in men treated with 150 mg/day bicalutamide monotherapy. In addition to testosterone and estradiol, there are smaller increases in concentrations of DHT, sex hormone-binding globulin, and prolactin. Estradiol levels with bicalutamide monotherapy are similar to those in the low-normal premenopausal female range while testosterone levels generally remain in the high end of the normal male range. Testosterone concentrations do not typically exceed the normal male range due to negative feedback on the HPG axis by the increased concentrations of estradiol. Bicalutamide influences the HPG axis and increases hormone levels only in men and not also in women. This is due to the much lower levels of androgens in women and their lack of basal suppression of the HPG axis in this sex. As evidenced by its effectiveness in the treatment of prostate cancer and other androgen-dependent conditions, the antiandrogenic actions of bicalutamide considerably exceed any impact of the increased levels of testosterone it results in. However, the elevated levels of estradiol remain unopposed by bicalutamide and are responsible for the gynecomastia and feminizing side effects it causes in men. Although bicalutamide monotherapy increases gonadotropin and sex hormone levels in men, this will not occur if bicalutamide is combined with an antigonadotropin such as a GnRH analogue, estrogen, or progestogen, as these medications maintain negative feedback on the HPG axis.NSAA monotherapy, including with bicalutamide, shows a number of tolerability differences from methods of androgen deprivation therapy that incorporate surgical or medical castration. For example, the rates of hot flashes, depression, fatigue, and sexual dysfunction are all much higher with GnRH analogues than with NSAA monotherapy. It is thought that this is because GnRH analogues suppress estrogen production in addition to androgen production, resulting in estrogen deficiency. In contrast, NSAA monotherapy does not decrease estrogen levels and in fact increases them, resulting in an excess of estrogens that compensates for androgen deficiency and allows for a preservation of mood, energy, and sexual function. Neurosteroids that are produced from testosterone like 3α-androstanediol and 3β-androstanediol, which are ERβ agonists and the former a potent GABAA receptor positive allosteric modulator, may also be involved. In the specific case of sexual dysfunction, an additional possibility for the difference is that without concomitant suppression of androgen production, blockade of the AR by the bicalutamide in the brain is incomplete and insufficient to markedly influence sexual function.Under normal circumstances, bicalutamide has no capacity to activate the AR. However, in prostate cancer, mutations and overexpression of the AR can accumulate in prostate gland cells which can convert bicalutamide from an antagonist of the AR into an agonist. This can result in paradoxical stimulation of prostate cancer growth with bicalutamide and is responsible for the phenomenon of the antiandrogen withdrawal syndrome, where antiandrogen discontinuation paradoxically slows the rate of prostate cancer growth.In transgender women, breast development is a desired effect of antiandrogen or estrogen treatment. Breast development and gynecomastia induced by bicalutamide is thought to be mediated by increased activation of the ER secondary to blockade of the AR (resulting in disinhibition of the ER in breast tissue) and increased levels of estradiol. In addition to fat deposition, connective tissue growth, and ductal development, bicalutamide has been found to produce moderate lobuloalveolar development of the breasts. However, full lobuloalveolar maturation necessary for lactation and breastfeeding will not occur without progestogen treatment.Bicalutamide monotherapy seems to have minimal effect on testicular spermatogenesis, testicular ultrastructure, and certain aspects of male fertility. This seems to be because testosterone levels in the testes (where ≈95% of testosterone in males is produced) are extremely high (up to 200-fold higher than circulating levels) and only a small fraction (less than 10%) of the normal levels of testosterone in the testes are actually necessary to maintain spermatogenesis. As a result, bicalutamide appears to not be able to compete with testosterone in this sole part of the body to an extent sufficient to considerably interfere with androgen signaling and function. However, while bicalutamide does not seem to be able to adversely influence testicular spermatogenesis, it may interfere with AR-dependent sperm maturation and transport outside of the testes in the epididymides and vas deferens where androgen levels are far lower, and hence may still be able to impair male fertility. In addition, the combination of bicalutamide with other medications, such as estrogens, progestogens, and GnRH analogues, can compromise spermatogenesis due to their own adverse effects on male fertility. These medications are able to strongly suppress gonadal androgen production, which can severely impair or abolish testicular spermatogenesis, and estrogens also appear to have direct and potentially long-lasting cytotoxic effects in the testes at sufficiently high concentrations.
Other activities
Bicalutamide has been found to act as an inhibitor or inducer of certain cytochrome P450 enzymes including CYP3A4, CYP2C9, CYP2C19, and CYP2D6 in preclinical research, but no evidence of this has been found in humans treated with up to 150 mg/day. It has also been identified in vitro as a strong inhibitor of CYP27A1 (cholesterol 27-hydroxylase) and as an inhibitor of CYP46A1 (cholesterol 24-hydroxylase), but this has yet to be assessed or confirmed in vivo or in humans and the clinical significance remains unknown. Bicalutamide has been found to be a P-glycoprotein (ABCB1) inhibitor. Like other first-generation NSAAs and enzalutamide, it has been found to act as a weak non-competitive inhibitor of GABAA receptor-mediated currents in vitro (IC50 = 5.2 μM). However, unlike enzalutamide, bicalutamide has not been found to be associated with seizures or other related adverse central effects, so the clinical relevance of this finding is uncertain.
Pharmacokinetics
Though its absolute bioavailability in humans is unknown, bicalutamide is known to be extensively and well-absorbed. Its absorption is not affected by food. The absorption of bicalutamide is linear at doses up to 150 mg/day and is saturable at doses above this, with no further increases in steady-state levels of bicalutamide occurring at doses above 300 mg/day. Whereas absorption of (R)-bicalutamide is slow, with levels peaking at 31 to 39 hours after a dose, (S)-bicalutamide is much more rapidly absorbed. Steady-state concentrations of the drug are reached after 4 to 12 weeks of treatment independently of dosage, with a 10- to 20-fold progressive accumulation in levels of (R)-bicalutamide. The long time to steady-state levels is the result of bicalutamides very long elimination half-life.The tissue distribution of bicalutamide is not well-characterized. The amount of bicalutamide in semen that could potentially be transferred to a female partner during sexual intercourse is low and is not thought to be important. Based on animal studies with rats and dogs it was thought that bicalutamide could not cross the blood–brain barrier and hence could not enter the brain. As such, it was initially thought to be a peripherally selective antiandrogen. However, subsequent clinical studies found that this was not also the case for humans, indicating species differences; bicalutamide crosses into the human brain and, in accordance, produces effects and side effects consistent with central antiandrogenic action. Bicalutamide is highly plasma protein bound (96.1% for racemic bicalutamide, 99.6% for (R)-bicalutamide) and is bound mainly to albumin, with negligible binding to SHBG and corticosteroid-binding globulin.Bicalutamide is metabolized in the liver. (R)-Bicalutamide is metabolized slowly and almost exclusively via hydroxylation by CYP3A4 into (R)-hydroxybicalutamide. This metabolite is then glucuronidated by UGT1A9. In contrast to (R)-bicalutamide, (S)-bicalutamide is metabolized rapidly and mainly by glucuronidation (without hydroxylation). None of the metabolites of |
Bicalutamide | bicalutamide are known to be active and levels of the metabolites are low in plasma, where unchanged biclautamide predominates. Due to the stereoselective metabolism of bicalutamide, (R)-bicalutamide has a far longer terminal half-life than (S)-bicalutamide and its levels are about 10- to 20-fold higher in comparison following a single dose and 100-fold higher at steady-state. (R)-Bicalutamide has a relatively long elimination half-life of 5.8 days with a single dose and 7 to 10 days following repeated administration.Bicalutamide is eliminated in similar proportions in feces (43%) and urine (34%), while its metabolites are eliminated roughly equally in urine and bile. The drug is excreted to a substantial extent in unmetabolized form, and both bicalutamide and its metabolites are eliminated mainly as glucuronide conjugates. The glucuronide conjugates of bicalutamide and its metabolites are eliminated from the circulation rapidly, unlike unconjugated bicalutamide.The pharmacokinetics of bicalutamide are not affected by consumption of food, a persons age or body weight, renal impairment, or mild-to-moderate hepatic impairment. However, steady-state levels of bicalutamide are higher in Japanese individuals than in white people.
Chemistry
Bicalutamide is a racemic mixture consisting of equal proportions of enantiomers (R)-bicalutamide (dextrorotatory) and (S)-bicalutamide (levorotatory). Its systematic name (IUPAC) is (RS)-N-[4-cyano-3-(trifluoromethyl)phenyl]-3-[(4-fluorophenyl)sulfonyl]-2-hydroxy-2-methylpropanamide. The compound has a chemical formula of C18H14F4N2O4S, a molecular weight of 430.373 g/mol, and is a fine white to off-white powder.The acid dissociation constant (pKa) of bicalutamide is approximately 12. It is a highly lipophilic compound (log P = 2.92). At 37 °C (98.6 °F), or normal human body temperature, bicalutamide is practically insoluble in water (4.6 mg/L), acid (4.6 mg/L at pH 1), and alkali (3.7 mg/L at pH 8). In organic solvents, it is slightly soluble in chloroform and absolute ethanol, sparingly soluble in methanol, and freely soluble in acetone and tetrahydrofuran.Bicalutamide is a synthetic and nonsteroidal compound which was derived from flutamide. It is a bicyclic compound (has two rings) and can be classified as and has variously been referred to as an anilide (N-phenylamide) or aniline, a diarylpropionamide, and a toluidide.
Analogues
First-generation NSAAs including bicalutamide, flutamide, and nilutamide are all synthetic, nonsteroidal anilide derivatives and structural analogues of each other. Bicalutamide is a diarylpropionamide while flutamide is a monoarylpropionamide and nilutamide is a hydantoin. Bicalutamide and flutamide, though not nilutamide, can also be classified as toluidides. All three of the compounds share a common 3-trifluoromethylaniline moiety. Bicalutamide is a modification of flutamide in which a 4-fluorophenylsulfonyl moiety has been added and the nitro group on the original phenyl ring has been replaced with a cyano group. Topilutamide, also known as fluridil, is another NSAA that is closely related structurally to the first-generation NSAAs, but, in contrast to them, is not used in the treatment of prostate cancer and is instead used exclusively as a topical antiandrogen in the treatment of pattern hair loss.
The second-generation NSAAs enzalutamide and apalutamide were derived from and are analogues of the first-generation NSAAs, while another second-generation NSAA, darolutamide, is said to be structurally distinct and chemically unrelated to the other NSAAs. Enzalutamide is a modification of bicalutamide in which the inter-ring linking chain has been altered and cyclized into a 5,5-dimethyl-4-oxo-2-thioxo imidazolidine moiety. In apalutamide, the 5,5-dimethyl groups of the imidazolidine ring of enzalutamide are cyclized to form an accessory cyclobutane ring and one of its phenyl rings is replaced with a pyridine ring.
The first nonsteroidal androgens, the arylpropionamides, were discovered via structural modification of bicalutamide. Unlike bicalutamide (which is purely antiandrogenic), these compounds show tissue-selective androgenic effects and were classified as selective androgen receptor modulators (SARMs). Lead SARMs of this series included acetothiolutamide, enobosarm (ostarine; S-22), and andarine (acetamidoxolutamide or androxolutamide; S-4). They are very close to bicalutamide structurally, with the key differences being that the linker sulfone of bicalutamide has been replaced with an ether or thioether group to confer agonism of the AR and the 4-fluoro atom of the pertinent phenyl ring has been substituted with an acetamido or cyano group to eliminate reactivity at the position.
A few radiolabeled derivatives of bicalutamide have been developed for potential use as radiotracers in medical imaging. They include [18F]bicalutamide, 4-[76Br]bromobicalutamide, and [76Br]bromo-thiobicalutamide. The latter two were found to have substantially increased affinity for the AR relative to that of bicautamide. However, none of these agents have been evaluated in humans.5N-Bicalutamide, or 5-azabicalutamide, is a minor structural modification of bicalutamide which acts as a reversible covalent antagonist of the AR and has approximately 150-fold higher affinity for the AR and about 20-fold greater functional inhibition of the AR relative to bicalutamide. It is among the most potent AR antagonists to have been developed and is being researched for potential use in the treatment of antiandrogen-resistant prostate cancer.
Synthesis
A number of chemical syntheses of bicalutamide have been published in the literature. The procedure of the first published synthesis of bicalutamide can be seen below.
History
Bicalutamide as well as all of the other currently marketed NSAAs were derived from structural modification of flutamide, which itself was originally synthesized as a bacteriostatic agent in 1967 at Schering Plough Corporation and was subsequently and serendipitously found to possess antiandrogenic activity. Bicalutamide was discovered by Tucker and colleagues at Imperial Chemical Industries (ICI) in the 1980s and was selected for development from a group of over 2,000 synthesized compounds. It was first patented in 1982 and was first reported in the scientific literature in June 1987.Bicalutamide was first studied in a phase I clinical trial in 1987 and the results of the first phase II clinical trial in prostate cancer were published in 1990. The pharmaceutical division of ICI was split out into an independent company called Zeneca in 1993, and in April and May 1995, Zeneca (now AstraZeneca, after merging with Astra AB in 1999) began pre-approval marketing of bicalutamide for the treatment of prostate cancer in the U.S.. It was first launched in the U.K. in May 1995, and was subsequently approved by the U.S. FDA on 4 October 1995, for the treatment of prostate cancer at a dosage of 50 mg/day in combination with a GnRH analogue.Following its introduction for use in combination with a GnRH analogue, bicalutamide was developed as a monotherapy at a dosage of 150 mg/day for the treatment of prostate cancer, and was approved for this indication in Europe, Canada, and a number of other countries in the late 1990s and early 2000s. This application of bicalutamide was also under review by the FDA in the U.S. in 2002, but ultimately was not approved in this country. In Japan, bicalutamide is licensed at a dosage of 80 mg/day alone or in combination with a GnRH analogue for prostate cancer. The unique 80 mg dosage of bicalutamide used in Japan was selected for development in this country on the basis of observed pharmacokinetic differences with bicalutamide in Japanese men.Subsequent to negative findings of bicalutamide monotherapy for LPC in the EPC clinical programme, approval of bicalutamide for use specifically in the treatment of LPC was withdrawn in a number of countries including the U.K. (in October or November 2003) and several other European countries and Canada (in August 2003). In addition, the U.S. and Canada explicitly recommended against the use of 150 mg/day bicalutamide for this indication. The drug is effective for, remains approved for, and continues to be used in the treatment of LAPC and mPC, on the other hand.The patent protection of bicalutamide expired in the U.S. in March 2009 and the drug has subsequently been available as a generic, at greatly reduced cost.Bicalutamide was the fourth antiandrogen (and the third NSAA) to be introduced for the treatment of prostate cancer, following the SAA CPA in 1973 and the NSAAs flutamide in 1983 (1989 in the U.S.) and nilutamide in 1989 (1996 in the U.S.). It has been followed by abiraterone acetate in 2011, enzalutamide in 2012, apalutamide in 2018, and darolutamide in 2019, and may also be followed by in-development drugs such as proxalutamide and seviteronel.
Society and culture
Generic names
Bicalutamide is the generic name of the drug in English and French and its INN, USAN, USP, BAN, DCF, AAN, and JAN. It is also referred to as bicalutamidum in Latin, bicalutamida in Spanish and Portuguese, bicalutamid in German, and bikalutamid in Russian and other Slavic languages. The "bica-" prefix corresponds to the fact that bicalutamide is a bicyclic compound, while the "-lutamide" suffix is the standard suffix for NSAAs. Bicalutamide is also known by its former developmental code name ICI-176,334.
Brand names
Bicalutamide is marketed by AstraZeneca in oral tablet form under the brand names Casodex, Cosudex, Calutide, Calumid, and Kalumid in many countries. It is also marketed under the brand names Bicadex, Bical, Bicalox, Bicamide, Bicatlon, Bicusan, Binabic, Bypro, Calutol, and Ormandyl among others in various countries. The drug is sold under a large number of generic trade names such as Apo-Bicalutamide, Bicalutamide Accord, Bicalutamide Actavis, Bicalutamide Bluefish, Bicalutamide Kabi, Bicalutamide Sandoz, and Bicalutamide Teva as well. A combination formulation of bicalutamide and goserelin is marketed by AstraZeneca in Australia and New Zealand under the brand name ZolaCos-CP.
Cost and generics
Bicalutamide is off-patent and available as a generic. Unlike bicalutamide, the newer NSAA enzalutamide is still on-patent, and for this reason, is considerably more expensive in comparison.The patent protection of all three of the first-generation NSAAs has expired and flutamide and bicalutamide are both available as low-cost generics. Nilutamide, on the other hand, has always been a poor third competitor to flutamide and bicalutamide and, in relation to this fact, has not been developed as a generic and is only available as brand name Nilandron, at least in the U.S.Bicalutamide is considerably less costly than GnRH analogues, which, in spite of some having been off-patent many years, have been reported (in 2013) to typically cost US$10,000–$15,000 per year (or about US$1,000 per month) of treatment.
Sales and usage
Sales of bicalutamide (as Casodex) worldwide peaked at US$1.3 billion in 2007, and it has been described as a "billion-dollar-a-year" drug prior to losing its patent protection starting in 2007. In 2014, despite the introduction of abiraterone acetate in 2011 and enzalutamide in 2012, bicalutamide was still the most commonly prescribed drug in the treatment of metastatic castration-resistant prostate cancer (mCRPC). Moreover, in spite of being off-patent, bicalutamide was said to still generate a few hundred million dollars in sales per year for AstraZeneca. Total worldwide sales of brand name Casodex were approximately US$13.4 billion as of the end of 2018.
Between January 2007 and December 2009 (a period of three years), 1,232,143 prescriptions of bicalutamide were dispensed in the U.S., or about 400,000 prescriptions per year. During that time, bicalutamide accounted for about 87.2% of the NSAA market, while flutamide accounted for 10.5% of it and nilutamide for 2.3% of it. Approximately 96% of bicalutamide prescriptions were written for diagnosis codes that clearly indicated neoplasm. About 1,200, or 0.1% of bicalutamide prescriptions were dispensed to pediatric patients (age 0–16).
Regulation
Bicalutamide is a prescription drug. It is not specifically a controlled substance in any country and therefore is not an illegal drug. However, the manufacture, sale, distribution, and possession of prescription drugs are all still subject to legal regulation throughout the world.
Research
Bicalutamide has been studied in combination with the 5α-reductase inhibitors finasteride and dutasteride in prostate cancer. It has also been studied in combination with raloxifene, a selective estrogen receptor modulator (SERM), for the treatment of prostate cancer. Bicalutamide has been tested for the treatment of AR-positive ER/PR-negative locally advanced and metastatic breast cancer in women in a phase II study for this indication. Enzalutamide is also being investigated for this type of cancer. Bicalutamide has also been studied in a phase II clinical trial for ovarian cancer in women.Bicalutamide has been studied in the treatment of benign prostatic hyperplasia (BPH) in a 24-week trial of 15 patients at a dosage of 50 mg/day. Prostate volume decreased by 26% in patients taking bicalutamide and urinary irritative symptom scores significantly decreased. Conversely, peak urine flow rates and urine pressure flow examinations were not significantly different between bicalutamide and placebo. The decrease in prostate volume achieved with bicalutamide was comparable to that observed with the 5α-reductase inhibitor finasteride, which is approved for the treatment of BPH. Breast tenderness (93%), gynecomastia (54%), and sexual dysfunction (60%) were all reported as side effects of bicalutamide at the dosage used in the study, although no treatment discontinuations due to adverse effects occurred and sexual functioning was maintained in 75% of patients.A phase III clinical trial of bicalutamide in combination with an ethinylestradiol-containing combined oral contraceptive for the treatment of severe hirsutism in women with PCOS was completed in Italy in 2017 under supervision of the Italian Agency for Drugs (AIFA).Antiandrogens have been suggested for treating COVID-19 in men and as of May 2020 high-dose bicalutamide is in a phase II clinical trial for this purpose.
Veterinary use
Bicalutamide may be used to treat hyperandrogenism and associated benign prostatic hyperplasia secondary to hyperadrenocorticism (caused by excessive adrenal androgens) in male ferrets. However, it has not been formally assessed in controlled studies for this purpose.
See also
Comparison of bicalutamide with other antiandrogens
References
Further reading
External links
"Bicalutamide". Drug Information Portal. U.S. National Library of Medicine. |
Perindopril | Perindopril is a medication used to treat high blood pressure, heart failure, or stable coronary artery disease.As a long-acting ACE inhibitor, it works by relaxing blood vessels and decreasing blood volume. As a prodrug, perindopril is hydrolyzed in the liver to its active metabolite, perindoprilat. It was patented in 1980 and approved for medical use in 1988.Perindopril is taken in the form of perindopril arginine (trade names include Coversyl, Coversum) or perindopril erbumine (Aceon). Both forms are therapeutically equivalent and interchangeable, but the dose prescribed to achieve the same effect differs between the two forms. It is also often combined with another medication, sometimes in the same tablet (see #Combinations below).
Medical uses
Perindopril shares the indications of ACE inhibitors as a class, including essential hypertension, stable coronary artery disease (reduction of risk of cardiac events in patients with a history of myocardial infarction and/or revascularization), treatment of symptomatic coronary artery disease or heart failure, and diabetic nephropathy.
Combination therapy
With indapamide
In combination with indapamide, perindopril has been shown to significantly reduce the progression of chronic kidney disease and renal complications in patients with type 2 diabetes. In addition, the Perindopril pROtection aGainst REcurrent Stroke Study (PROGRESS) found that whilst perindopril monotherapy demonstrated no significant benefit in reducing recurrent strokes when compared to placebo, the addition of low dose indapamide to perindopril therapy was associated with larger reductions in both blood pressure lowering and recurrent stroke risk in patients with pre-existing cerebrovascular disease, irrespective of their blood pressure. There is evidence to support the use of perindopril and indapamide combination over perindopril monotherapy to prevent strokes and improve mortality in patients with a history of stroke, transient ischaemic attack or other cardiovascular disease.
With amlodipine
The Anglo-Scandinavian Cardiac Outcomes Trial-Blood Pressure Lowering Arm (ASCOT-BLA) was a 2005 landmark trial that compared the effects of the established therapy of the combination of atenolol and bendroflumethiazide to the new drug combination of amlodipine and perindopril (trade names Viacoram, AceryCal etc.). The study of more than 19 000 patients world-wide was terminated earlier than anticipated because it clearly demonstrated a statistically significant improvement in mortality and cardiovascular outcomes with the newer treatment. The combination of amlodipine and perindopril remains in the current treatment guidelines for hypertension and the outcomes of the ASCOT-BLA trial paved the way for further research into combination therapy and newer agents.
Contraindications
Children
Pregnancy
Lactation
Situations where a patient has a history of hypersensitivity
Kidney failure
Precautions
Assess kidney function before and during treatment where appropriate.
Renovascular hypertension
Surgery/anesthesia
An analysis on the PROGRESS trial showed that perindopril has key benefits in reducing cardiovascular events by 30% in patients with chronic kidney disease defined as a CrCl <60ml/min. A 2016 and 2017 meta-analysis review looking at ACE inhibitors demonstrated a reduction in cardiovascular events but also slowed the decline of renal failure by 39% when compared to placebo. These studies included patients with moderate to severe kidney disease and those on dialysis.
Its renoprotective benefits of decreasing blood pressure and removing filtration pressure is highlighted in a 2016 review. ACE inhibitor can result in an initial increase of serum creatinine, but mostly returns to baseline in a few weeks in majority of patients. It has been suggested that increased monitoring, especially in advanced kidney failure, will minimise any related risk and improve long-term benefits.
Use cautiously in patients with sodium or volume depletion due to potential excessive hypotensive effects of renin-angiotensin blockade causing symptomatic hypotension. Careful monitoring or short-term dose reduction of diuretics prior to commencing perindopril is recommended to prevent this potential effect. A diuretic may later be given in combination if necessary; potassium-sparing diuretics are not recommended in combination with perindopril due to the risk of hyperkalaemia.
Combination with neuroleptics or imipramine-type drugs may increase the blood pressure lowering effect. Serum lithium concentrations may rise during lithium therapy.
Side effects
Side effects are mild, usually at the start of treatment; they include:
Cough
Fatigue
Weakness/Asthenia
Headache
Disturbances of mood and/or sleepLess often
Taste impairment
Epigastric discomfort
Nausea
Abdominal pain
RashReversible increases in blood urea and creatinine may be observed. Proteinuria has occurred in some patients. Rarely, angioneurotic edema and decreases in hemoglobin, red cells, and platelets have been reported.
Composition
Each tablet contains 2, 4, or 8 mg of the tert-butylamine salt of perindopril. Perindopril is also available under the trade name Coversyl Plus, containing 4 mg of perindopril combined with 1.25 mg indapamide, a thiazide-like diuretic.
In Australia, each tablet contains 2.5, 5, or 10 mg of perindopril arginine. Perindopril is also available under the trade name Coversyl Plus, containing 5 mg of perindopril arginine combined with 1.25 mg indapamide and Coversyl Plus LD, containing 2.5 mg of perindopril arginine combined with 0.625 mg indapamide.
The efficacy and tolerability of a fixed-dose combination of 4 mg perindopril and 5 mg amlodipine, a calcium channel antagonist, has been confirmed in a prospective, observational multicenter trial of 1,250 hypertensive patients. A preparation of the two drugs is available commercially as Coveram.
Society and culture
Trade names
Perindopril is available under the following brand names among others:
Marketing
On 9 July 2014, the European Commission imposed fines of €427,700,000 on Laboratoires Servier and 5 companies which produce generics due to Serviers abuse of their dominant market position, in breach of European Union Competition law. Serviers strategy had included acquiring the principal source of generic production of Perindopril and entering into several pay-for-delay agreements with potential generic competitors.
References
Further reading
External links
Official website
Media related to Perindopril at Wikimedia Commons |
Aztreonam | Aztreonam, sold under the brand name Azactam among others, is an antibiotic used primarily to treat infections caused by gram-negative bacteria such as Pseudomonas aeruginosa. This may include bone infections, endometritis, intra abdominal infections, pneumonia, urinary tract infections, and sepsis. It is given by intravenous or intramuscular injection or by inhalation.Common side effects when given by injection include pain at the site of injection, vomiting, and rash. Common side effects when inhaled include wheezing, cough, and vomiting. Serious side effects include Clostridium difficile infection and allergic reactions including anaphylaxis. Those who are allergic to other β-lactam have a low rate of allergy to aztreonam. Use in pregnancy appears to be safe. It is in the monobactam family of medications. Aztreonam inhibits cell wall synthesis by blocking peptidoglycan crosslinking to cause bacterial death.Aztreonam was approved for medical use in the United States in 1986. It was removed from the World Health Organizations List of Essential Medicines in 2019. It is available as a generic medication. It is a manufactured version of a chemical from the bacterium Chromobacterium violaceum.
Medical uses
Nebulized forms of aztreonam are used to treat infections that are complications of cystic fibrosis and are approved for such use in Europe and the US; they are also used off-label for non-CF bronchiectasis, ventilator-associated pneumonia, chronic obstructive pulmonary disease, mycobacterial disease, and to treat infections in people who have received lung transplants.Aztreonam has strong activity against susceptible Gram-negative bacteria, including Pseudomonas aeruginosa. It is resistant to some beta-lactamases, but is inactivated by extended-spectrum beta-lactamases.
It has no useful activity against Gram-positive bacteria or anaerobes. It is known to be effective against a wide range of bacteria including Citrobacter, Enterobacter, E. coli, Haemophilus, Klebsiella, Proteus, and Serratia species. The following represents minimum inhibitory concentration (MIC) susceptibility data for a few medically significant microorganisms.
Staphylococcus aureus 8 - >128 μg/ml
Staphylococcus epidermidis 8 - 32 μg/ml
Streptococcus pyogenes 8 - ≥128 μg/mlSynergism between aztreonam and arbekacin or tobramycin against P. aeruginosa has been suggested.
Spectrum of activity
Acinetobacter anitratus, Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis are generally susceptible to aztreonam, while some staphylococci, Staphylococcus aureus, Staphylococcus haemolyticus and Xanthomonas maltophilia are resistant to it. Furthermore, Aeromonas hydrophila, Citrobacter koseri (Citrobacter diversus), Pantoea agglomerans (Enterobacter agglomerans), Haemophilus spp. and Streptococcus pyogenes have developed resistance to aztreonam to varying degrees.Aztreonam can be safely used in patients with a penicillin or cephalosporin allergy (except for patients with a ceftazidime allergy as ceftazidime and aztreonam share a similar side chain). It is also frequently used as an alternative to aminoglycosides because is not ototoxic or nephrotoxic.Aztreonam use has been recently reconsidered for human infections sustained by metallo-beta-lactamase (MBL)-producing Gram-negative bacteria. In these circumstances aztreonam is combined with avibactam (ceftazidime/avibactam). The combination of aztreonam and avibactam has demonstrated to be active against 80% of MBL isolates reaching a clinical infection resolution in 80% of MBL-infected patients.
Administration
Aztreonam is poorly absorbed when given orally, so it must be administered as an intravenous or intramuscular injection (trade name Azactam), or inhaled (trade name Cayston) using an ultrasonic nebulizer. In the United States, the Food and Drug Administration (FDA) approved the inhalation form on 22 February 2010, for the suppression of P. aeruginosa infections in patients with cystic fibrosis. It received conditional approval for administration in Canada and the European Union in September 2009, and has been fully approved in Australia.
Side effects
Reported side effects include injection site reactions, rash, and rarely toxic epidermal necrolysis. Gastrointestinal side effects generally include diarrhea and nausea and vomiting. There may be drug-induced eosinophilia. Because of the unfused beta-lactam ring there is somewhat lower cross-reactivity between aztreonam and many other beta-lactam antibiotics, and it may be safe to administer aztreonam to many patients with hypersensitivity (allergies) to penicillins and nearly all cephalosporins. There is a much lower risk of cross-sensitivity between aztreonam and other beta-lactam antibiotics than within other beta-lactam antibiotics. However, there is a higher chance of cross-sensitivity if a person is specifically allergic to ceftazidime, a cephalosporin. Aztreonam exhibits cross-sensitivity with ceftazidime due to a similar side chain.
Mechanism of action
Aztreonam is similar in action to penicillin. It inhibits synthesis of the bacterial cell wall, by blocking peptidoglycan crosslinking. It has a very high affinity for penicillin-binding protein-3 and mild affinity for penicillin-binding protein-1a. Aztreonam binds the penicillin-binding proteins of Gram-positive and anaerobic bacteria very poorly and is largely ineffective against them. Aztreonam is bactericidal, but less so than some of the cephalosporins.
References
External links
"Aztreonam". Drug Information Portal. U.S. National Library of Medicine. |
Isosorbide dinitrate | Isosorbide dinitrate (ISDN) is a medication used for heart failure, esophageal spasms, and to treat and prevent chest pain from not enough blood flow to the heart. It has been found to be particularly useful in heart failure due to systolic dysfunction together with hydralazine. It is taken by mouth or under the tongue.Common side effects include headache, lightheadedness with standing, and blurred vision. Severe side effects include low blood pressure. It is unclear if use in pregnancy is safe for the baby. It should not be used together with medications within the sildenafil family. ISDN is in the nitrate family of medications and works by dilating blood vessels.Isosorbide dinitrate was first written about in 1939. It is on the World Health Organizations List of Essential Medicines. ISDN is available as a generic medication. A long-acting form exists.
Medical uses
It is used for angina, in addition to other medications for congestive heart failure, and for esophageal spasms. It is available as an oral tablet both in extended release and slow release. The onset of action for Isosorbide Dinitrate is thirty minutes and the onset of action for oral extended release is 12–24 hours.
Long-acting nitrates can be more useful as they are generally more effective and stable in the short term.
Side effects
After long-term use for treating chronic conditions, tolerance may develop in patients, reducing its effectiveness. The mechanisms of nitrate tolerance have been thoroughly investigated in the last 30 years and several hypotheses have been proposed. These include:
Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); fainting; fast or slow heartbeat; nausea; new or worsening chest pain; vomiting.
Impaired biotransformation of ISDN to its active principle NO (or a NO-related species)
Neurohormonal activation, causing sympathetic activation and release of vasoconstrictors such as endothelin and angiotensin II which counteract the vasodilation induced by ISDN
Plasma volume expansion
The oxidative stress hypothesis (proposed by Munzel et al. in 1995)The last hypothesis might represent a unifying hypothesis, and an ISDN-induced inappropriate production of oxygen free radicals might induce a number of abnormalities which include the ones described above.
Furthermore, nitrate tolerance is shown to be associated with vascular abnormalities which have the potential to worsen patients prognosis: these include endothelial and autonomic dysfunction.
In the short run, ISDN can cause severe headaches, necessitating analgesic (very rarely up to morphine) administration for relief of pain, as well as severe hypotension, and, in certain cases, bradycardia. This makes some physicians nervous and should prompt caution when starting nitrate administration.
Mechanism of action
Similar to other nitrites and organic nitrates, isosorbide dinitrate is converted to nitric oxide (NO), an active intermediate compound which activates the enzyme guanylate cyclase (atrial natriuretic peptide receptor A). This stimulates the synthesis of cyclic guanosine 3,5-monophosphate (cGMP) which then activates a series of protein kinase-dependent phosphorylations in the smooth muscle cells, eventually resulting in the dephosphorylation of the myosin light chain of the smooth muscle fiber. The subsequent sequestration of calcium ions results in the relaxation of the smooth muscle cells and vasodilation.
Society and culture
Isosorbide dinitrate is sold in the US under the brand names Dilatrate-SR by Schwarz and Isordil by Valeant, according to FDA Orange Book. In the United Kingdom, Argentina, and Hong Kong, a trade name of it is Isoket. It is also a component of BiDil.
References
External links
"Isosorbide cinitrate". Drug Information Portal. U.S. National Library of Medicine. |
Dactinomycin | Dactinomycin, also known as actinomycin D, is a chemotherapy medication used to treat a number of types of cancer. This includes Wilms tumor, rhabdomyosarcoma, Ewings sarcoma, trophoblastic neoplasm, testicular cancer, and certain types of ovarian cancer. It is given by injection into a vein.Most people develop side effects. Common side effects include bone marrow suppression, vomiting, mouth ulcers, hair loss, liver problems, infections, and muscle pains. Other serious side effects include future cancers, allergic reactions, and tissue death at the site of injection. Use in pregnancy may harm the baby. Dactinomycin is in the cytotoxic antibiotic family of medications. It is believed to work by blocking the creation of RNA.Dactinomycin was approved for medical use in the United States in 1964. It is on the World Health Organizations List of Essential Medicines.
Medical use
Actinomycin is a clear, yellowish liquid administered intravenously and most commonly used in treatment of a variety of cancers, including:
Gestational trophoblastic neoplasia
Wilms tumor
Rhabdomyosarcoma
Ewings sarcoma
Malignant hydatidiform moleSometimes it will be combined with other drugs in chemotherapy regimens, like the VAC regimen (with vincristine and cyclophosphamide) for treating rhabdomyosarcoma and Ewings sarcoma.
It is also used as a radiosensitizer in adjunct to radiotherapies, since it can increase the radiosensitivity of tumor cells by inhibiting repair of sublethal radiation damage and delay the onset of the compensatory hyperplasia that occurs following irradiation.
Side effects
Common adverse drug reaction includes bone marrow suppression, fatigue, hair loss, mouth ulcer, loss of appetite and diarrhea. Actinomycin is a vesicant, if extravasation occurs.
Mechanism
In cell biology, actinomycin D is shown to have the ability to inhibit transcription. Actinomycin D does this by binding DNA at the transcription initiation complex and preventing elongation of RNA chain by RNA polymerase.
History
Actinomycin D was the first antibiotic shown to have anti-cancer activity. It was first isolated by Selman Waksman and his co-worker H. Boyd Woodruff in 1940. It was approved by the U.S. Food and Drug Administration (FDA) on December 10, 1964, and launched by Merck Sharp and Dohme under the trade name Cosmegen.
Research use
Because actinomycin can bind DNA duplexes, it can also interfere with DNA replication, although other chemicals such as hydroxyurea are better suited for use in the laboratory as inhibitors of DNA synthesis.
Actinomycin D and its fluorescent derivative, 7-aminoactinomycin D (7-AAD), are used as stains in microscopy and flow cytometry applications. The affinity of these stains/compounds for GC-rich regions of DNA strands makes them excellent markers for DNA. 7-AAD binds to single stranded DNA; therefore it is a useful tool in determining apoptosis and distinguishing between dead cells and live ones.
References
External links
"Dactinomycin". Drug Information Portal. U.S. National Library of Medicine. |
Bamlanivimab/etesevimab | Bamlanivimab/etesevimab is a combination of two monoclonal antibodies, bamlanivimab and etesevimab, administered together via intravenous infusion as a treatment for COVID-19. Both types of antibody target the surface spike protein of SARS‑CoV‑2.Bamlanivimab and etesevimab, administered together, are authorized in the United States for the treatment of mild-to-moderate COVID-19 in people aged twelve years of age and older weighing at least 40 kilograms (88 lb) with positive results of direct SARS-CoV-2 viral testing, and who are at high risk for progression to severe COVID-19, including hospitalization or death. They are also authorized, when administered together, for use after exposure to the SARS-CoV-2 virus for post-exposure prophylaxis (PEP) for COVID-19 and are not authorized for pre-exposure prophylaxis to prevent COVID-19 before being exposed to the SARS-CoV-2 virus.In January 2022, the U.S. Food and Drug Administration (FDA) revised the authorizations for two monoclonal antibody treatments – bamlanivimab/etesevimab (administered together) and casirivimab/imdevimab – to limit their use to only when the recipients are likely to have been infected with or exposed to a variant that is susceptible to these treatments. Because data show these treatments are highly unlikely to be active against the omicron variant, which is circulating at a very high frequency throughout the United States, these treatments are not authorized for use in any U.S. states, territories, and jurisdictions at this time.
Contents
Etesevimab
Etesevimab is a monoclonal antibody against the surface spike protein of SARS‑CoV‑2.Eli Lilly licensed etesevimab from Junshi Biosciences.
Bamlanivimab
Bamlanivimab is an IgG1 monoclonal antibody (mAb) directed against the spike protein of SARS‑CoV‑2. The aim is to block viral attachment and entry into human cells, thus neutralizing the virus, and help preventing and treating COVID-19.
Trials
The data supporting the emergency use authorization (EUA) for bamlanivimab and etesevimab are based on a randomized, double-blind, placebo-controlled clinical trial in 1,035 non-hospitalized participants with mild to moderate COVID-19 symptoms who were at high risk for progressing to severe COVID-19. Of these participants, 518 received a single infusion of bamlanivimab 2,800 milligrams and etesevimab 2,800 milligrams together, and 517 received placebo. The primary endpoint was COVID-19 related hospitalizations or death by any cause during 29 days of follow-up. Hospitalization or death occurred in 36 (7%) participants who received placebo compared to 11 (2%) participants treated with bamlanivimab 2,800 milligrams and etesevimab 2,800 milligrams administered together, a 70% reduction. All ten deaths (2%) occurred in the placebo group. Thus, all-cause death was significantly lower in the bamlanivimab 2,800-milligram and etesevimab 2,800-milligram group than the placebo group.
Economics
On 26 February 2021, the United States government agreed to purchase 100,000 doses of the drug for $210 million, at $2,100 per dose.
Research
COVID-19
In February 2021, the FDA issued an emergency use authorization (EUA) for bamlanivimab and etesevimab administered together for the treatment of mild to moderate COVID-19 in people twelve years of age or older weighing at least 40 kilograms (88 lb) who test positive for SARS‑CoV‑2 and who are at high risk for progressing to severe COVID-19. The authorized use includes treatment for those who are 65 years of age or older or who have certain chronic medical conditions. While bamlanivimab and etesevimab administered together resulted in a lower risk of resistant viruses developing during treatment compared with bamlanivimab administered alone, both treatments are available under an EUA and are expected to benefit people at high risk of disease progression. On 16 April 2021, the FDA revoked the emergency use authorization (EUA) that allowed for the investigational monoclonal antibody therapy bamlanivimab, when administered alone, to be used for the treatment of mild-to-moderate COVID-19 in adults and certain pediatric patients. The EUA was issued to Eli Lilly and Co.In February 2021, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) started rolling reviews of data on the use of the monoclonal antibodies casirivimab/imdevimab, bamlanivimab/etesevimab, and bamlanivimab for the treatment of COVID-19. In March 2021, the CHMP concluded that bamlanivimab and etesevimab can be used together to treat confirmed COVID-19 in people who do not require supplemental oxygen and who are at high risk of their COVID-19 disease becoming severe. The CHMP also looked at the use of bamlanivimab alone and concluded that, despite uncertainties around the benefits of monotherapy, it can be considered a treatment option. In October 2021, the CHMP ended the rolling review of bamlanivimab/etesevimab.
References
This article incorporates public domain material from the United States Department of Health and Human Services.
External links
"Bamlanivimab". Drug Information Portal. U.S. National Library of Medicine.
"Etesevimab". Drug Information Portal. U.S. National Library of Medicine.
Emergency Use Authorization (EUA) review for bamlanivimab
Emergency Use Authorization (EUA) for bamlanivimab/etesevimab
Frequently Asked Questions on the Emergency Use Authorization for bamlanivimab and etesevimab |
Besifloxacin | Besifloxacin (INN/USAN) is a fourth-generation fluoroquinolone antibiotic. The marketed compound is besifloxacin hydrochloride.
It was developed by SSP Co. Ltd., Japan, and designated SS734. SSP licensed U.S. and European rights to SS734 for ophthalmic use to InSite Vision Incorporated (OTC Pink: INSV) in 2000. InSite Vision developed an eye drop formulation (ISV-403) and conducted preliminary clinical trials before selling the product and all rights to Bausch & Lomb in 2003.The eye drop was approved by the United States Food and Drug Administration (FDA) on May 29, 2009, and marketed under the trade name Besivance.
Pharmacodynamics
Besifloxacin is a fluoroquinolone that has a broad spectrum in vitro activity against a wide range of Gram-positive and Gram-negative ocular pathogens: e.g., Corynebacterium pseudodiphtheriticum, Moraxella lacunata, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus hominis, Streptococcus mitis, Streptococcus oralis, Streptococcus pneumoniae and Streptococcus salivarius.
Besifloxacin has been found to inhibit production of pro-inflammatory cytokines in vitro.
The mechanism of action of besifloxacin involves inhibition of two enzymes which are essential for the synthesis and replication of bacterial DNA: the bacterial DNA gyrase and topoisomerase IV. Clinical trials indicated that Besifloxacin was 91% effective at eliminating the causative bacteria after five days, compared to 60% in the placebo group. This did not, however necessarily correlate with condition resolution, as bacterial presence is only a part of conjunctivitis.
Medical use
Besifloxacin is indicated in the treatment of bacterial conjunctivitis caused by sensitive bacteria, as well as in the prevention of infectious complications in patients undergoing laser therapy for the treatment of cataracts. It has been approved for use in children, adults, and the elderly, with clinically proven efficacy and safety from age one and older.Besifloxacin is available as a 0.6% ophthalmological suspension, and dosing is 3 times a day, 4 to 12 hours apart for 7 days, regardless of age or condition.
Adverse effects
During the treatment, the most frequently reported ocular adverse reaction was the appearance of conjunctival redness (approximately 2% of patients). Other possible adverse reactions, reported in subjects treated with besifloxacin were: blurred vision, eye pain, eye irritation, eye pruritus and headache.
== References == |
Cefadroxil | Cefadroxil (formerly trademarked as Duricef) is a broad-spectrum antibiotic of the cephalosporin type, effective in Gram-positive and Gram-negative bacterial infections. It is a bactericidal antibiotic.
It was patented in 1967 and approved for medical use in 1978.
Medical use
Cefadroxil is a first-generation cephalosporin antibacterial drug that is the para-hydroxy derivative of cephalexin, and is used similarly in the treatment of mild to moderate susceptible infections such as the bacterium Streptococcus pyogenes, causing the disease popularly called strep throat or streptococcal tonsillitis, urinary tract infection, reproductive tract infection, and skin infections.
Cefadroxil is used as an antibiotic prophylaxis before dental procedures, for patients allergic to penicillins.
Spectrum of bacterial resistance and susceptibility
Cefadroxil has a broad spectrum of activity and has been effective in treating bacteria responsible for causing tonsillitis, and infections of the skin and urinary tract. Cefadroxil covers similar organisms to Cephalexin given that it is a derivative drug. The following represents MIC susceptibility data for a few medically significant microorganisms.
Escherichia coli: 8 μg/ml
Staphylococcus aureus: 1 – 2 μg/ml
Streptococcus pneumoniae: ≤1 – >16 μg/ml
Side effects
The most common side effects of cefadroxil are diarrhea (which, less commonly, may be bloody), nausea, upset stomach, and vomiting. Other side effects includerashes, hives, and itching.
Pharmacokinetics
Cefadroxil is almost completely absorbed from the gastrointestinal tract. After doses of 500 mg and 1 g by mouth, peak plasma concentrations of about 16 and 30 micrograms/ml, respectively, are obtained after 1.5 to 2.0 hours. Although peak concentrations are similar to those of cefalexin, plasma concentrations are more sustained. Dosage with food does not appear to affect the absorption of cefadroxil. About 20% of cefadroxil is reported to be bound to plasma proteins. Its plasma half-life is about 1.5 hours and is prolonged in patients with renal impairment.
Cefadroxil is widely distributed to body tissues and fluids. It crosses the placenta and appears in breast milk. More than 90% of a dose of cefadroxil may be excreted unchanged in the urine within 24 hours by glomerular filtration and tubular secretion; peak urinary concentrations of 1.8 mg/ml have been reported after a dose of 500 mg. Cefadroxil is removed by haemodialysis.
Dosage
Cefadroxil is given by mouth, and doses are expressed in terms of the anhydrous substance; 1.04 g of cefadroxil monohydrate is equivalent to about 1 g of anhydrous cefadroxil.
Veterinary use
It can be used for treating infected wounds on animals. Usually in powder form mixed with water, it has a color and smell similar to Tang. Given orally to animals, the amount is dependent on their weight and severity of infection.
== References == |
Cromoglicic acid | Cromoglicic acid (INN)—also referred to as cromolyn (USAN), cromoglycate (former BAN), or cromoglicate—is traditionally described as a mast cell stabilizer, and is commonly marketed as the sodium salt sodium cromoglicate or cromolyn sodium. This drug prevents the release of inflammatory chemicals such as histamine from mast cells.
Cromoglicic acid has been the non-corticosteroid treatment of choice in the treatment of asthma, for which it has largely been replaced by leukotriene receptor antagonists because of their convenience (and perceived safety). Cromoglicic acid requires administration four times daily, and does not provide additive benefit in combination with inhaled corticosteroids.
History
Cromolyn sodium was discovered in 1965 by Roger Altounyan, a pharmacologist who had asthma. It is considered a breakthrough drug in management of asthma, as the patients can be freed from steroids in many cases; however, it is mainly effective as a prophylaxis for allergic and exercise-induced asthma, not as a treatment for acute attacks. Altounyan was investigating certain plants and herbs which have bronchodilating properties. One such plant was khella (Ammi visnaga) which had been used as a muscle relaxant since ancient times in Egypt. Altounyan deliberately inhaled derivatives of the active ingredient khellin to determine if they could block his asthma attacks. After several years of trial he isolated an effective and safe asthma-preventing compound called cromolyn sodium.
Preparations
Cromoglicic acid is available in multiple forms:
as a nasal spray (Rynacrom (UK), Lomusol (France), Nasalcrom (the only over-the-counter form, US), Prevalin (non-direct version, NL)) to treat allergic rhinitis.
in a nebulizer solution for aerosol administration to treat asthma.
as an inhaler (Intal, Fisons Pharmaceuticals, UK) for preventive management of asthma. The maker of Intal, King Pharmaceuticals, has discontinued manufacturing the inhaled form, cromolyn sodium inhalation aerosol, due to issues involving CFC-free propellant. As stocks are depleted, this inhaler preparation will no longer be available to patients. In the EU it is manufactured without CFCs by Sanofi, although it must be imported from Canada or Mexico for USA residents.
as eye drops (Opticrom and Optrex Allergy (UK), Crolom, Cromolyn (Canada)) for allergic conjunctivitis
in an oral form (Gastrocrom, Nalcrom) to treat mastocytosis, mast cell activation syndrome, dermatographic urticaria and ulcerative colitis. Another oral product, Intercron (sodium cromoglicate in distilled water, from Zambon France), is used for food allergies.
Mechanism of action
"Cromolyn works because it prevents the release of mediators that would normally attract inflammatory cells and because it stabilizes the inflammatory cells. MCT mast cells found in the mucosa are stabilised." Nedocromil is another mast cell stabilizer that also works in controlling asthma.
The underlying mechanism of action is not fully understood; for while cromoglicate stabilizes mast cells, this mechanism is probably not why it works in asthma. Pharmaceutical companies have produced 20 related compounds that are equally or more potent at stabilising mast cells and none of them have shown any anti-asthmatic effect. It is more likely that these work by inhibiting the response of sensory C fibers to the irritant capsaicin, inhibiting local axon reflexes involved in asthma, and may inhibit the release of preformed T cell cytokines and mediators involved in asthma. (see review by Garland, 1991)
It is known to somewhat inhibit chloride channels (37% ± 7%) and thus may inhibit the:
exaggerated neuronal reflexes triggered by stimulation of irritant receptors on sensory nerve endings (e.g. exercise-induced asthma)
release of preformed cytokines from several type of inflammatory cells (T cells, eosinophils) in allergen-induced asthmaNote: Another chemical (NPPB: 5-nitro-2(3-phenyl) propylamino-benzoic acid) was shown, in the same study, to be a more effective chloride channel blocker.
Finally it may act by inhibiting calcium influx.
Cromoglicate is classified as a chromone.
Cromolyn is also being tested as a drug to treat insulin-induced lipoatrophy and Alzheimers disease in combination with Ibuprofen. Cromolyn is also known to bind S100P protein and disrupt the interaction with RAGE.
Synthesis
== References == |
Ospemifene | Ospemifene (brand names Osphena and Senshio produced by Shionogi) is an oral medication indicated for the treatment of dyspareunia – pain during sexual intercourse – encountered by some women, more often in those who are post-menopausal. Ospemifene is a selective estrogen receptor modulator (SERM) acting similarly to an estrogen on the vaginal epithelium, building vaginal wall thickness which in turn reduces the pain associated with dyspareunia. Dyspareunia is most commonly caused by "vulvar and vaginal atrophy."The medication was approved by the FDA in February 2013 and by the European Commission for marketing in the EU in January 2015.
Medical uses
Ospemifene is used to treat dyspareunia. In the US it is indicated for the treatment of moderate to severe dyspareunia, a symptom of vulvar and vaginal atrophy (VVA), due to menopause. In the EU it is indicated for the treatment of moderate to severe symptomatic VVA in post-menopausal women who are not candidates for local vaginal oestrogen therapy.
Contraindications
Women with "undiagnosed abnormal genital bleeding; known or suspected estrogen-dependent neoplasia; active or history of deep vein thrombosis; pulmonary embolism; arterial thromboembolic disease; and are or may become pregnant" or "with known or suspected breast cancer or those with extreme hepatic impairment" should not take ospemifene. This is not a full list of contraindications.
Side effects
Side effects associated with ospemifene include vaginal discharge, hot flashes, and diaphoresis. More serious adverse effects are similar to those of estrogens and estrogen receptor modulators. These include, but are not limited to, thromboembolism, allergic reactions, fatigue, and headache, and others could occur. There are other additional adverse effects.
Ospemifene is a selective estrogen receptor modulator. As such, many of the effects produced by estrogens are produced by ospemifene. The boxed warning of the medication indicates ospemifene may thicken the endometrium, which could lead to unusual bleeding and endometrial cancer. For women taking estrogens, concurrently taking a type of drug called a progestin has been shown to decrease the occurrence of endometrial hyperplasia. In theory, progestins may be expected to attenuate ospemifenes effects on endometrial thickening. However clinical trials confirming this have not been conducted. Like estrogens, ospemifene also may increase the risk for cardiovascular events, including "stroke, coronary heart disease, venous thromboembolism," and others. The risk of thrombotic and hemorrhagic strokes is given as 0.72 and 1.45 per 1,000 women, while that of deep vein thrombosis is estimated to be 1.45 per 1,000 women. The risks of these adverse events in women taking ospemifene are lower than those in women taking estrogen alone in the form of oral conjugated estrogens. Studies have not documented the relative risk compared with women taking estrogen/progestin therapy.
Pharmacology
Pharmacodynamics
Ospemifene is "an estrogen agonist/antagonist that makes vaginal tissue thicker and less fragile resulting in a reduction in the amount of pain women experience with sexual intercourse." This medication should be used for the shortest amount of time possible due to associated adverse effects. Ospemifene might not have an adverse influence on coagulation, in contrast to estrogens and other SERMs like tamoxifen and raloxifene.A binding assay was also performed to measure the affinity of ospemifene for the estrogen receptor (ERα and ERβ). The study showed that ospemifene bound ERα and ERβ with similar affinity. Ospemifene bound the estrogen receptors with a lower affinity than estradiol. Ospemifene was shown to be an antagonist of "ERE-mediated transactivation on MCF-7 cells," which the authors concluded indicates "anti-estrogenic activity in breast cancer cells."
Pharmacokinetics
The pharmacokinetics of ospemifene were dose-dependent over a dose range of 10 to 800 mg/day.
History
Approval process
Hormos Medical Ltd., which is a part of QuatRx Pharmaceuticals, filed a patent on January 19, 2005, for a solid dosage form of ospemifene. In March 2010, QuatRX Pharmaceuticals licensed ospemifene to Shionogi & Co., Ltd. for clinical development and marketing. A New Drug Application (NDA) was submitted to the FDA on April 26, 2012. Amendments to the NDA were submitted in June, July, August, October, and November 2012, and January and February 2013. It was ultimately approved by the FDA on February 26, 2013. Ospemifene (under the brand name Senshio) was subsequently approved by the European Commission for marketing in the EU in January 2015.
Preclinial and clinical trials
Preclinical trials were performed in ovariectomized rats to model menopause. Oral ospemifene was compared with raloxifene (another SERM), its metabolites 4-hydroxy ospemifene and 4-hydroxy ospemifene, estradiol, and ospemifene administered as an intravaginal suppository. Estradiol was used as a positive control and raloxifene was used because it is in the same drug class as ospemifene. Multiple doses of oral ospemifene were tested. 10 mg/kg/day of Ospemifene was found to cause a greater increase in vaginal weight and vaginal epithelial height than 10 mg/kg/day of raloxifene. Vaginal weight had a 1.46x increase after a two-week treatment of 10 mg/kg/day of ospemifene. The number of progesterone receptors was increased in the vaginal stroma and epithelium, which indicates that ospemifene has "estrogenic activity."Two 12-week phase 3 clinical trials were performed for ospemifene. One evaluated the effects of Ospemifene on vaginal tissue thickness, composition and vaginal pH. The other evaluated the effects of Ospemifene on vaginal tissue and on symptoms of dyspareunia. Between the two trials, 4 signs and symptoms were measured. These included three tissue-related signs, two of which represented histological changes in the vaginal tissue (change in percent parabasal cells and change in percent superficial cells) and the third was "change in vaginal pH". Dyspareunia was evaluated in one of the trials. It was defined as "change in most bothersome symptom" of discomfort during sexual activity and further limited to symptoms of either vaginal dryness or vaginal pain." Ospemifene produced more changes in vaginal tissue and greater reduction in dyspareunia symptoms than placebo. A dose-response also was observed in the trial; ospemifene 60 mg had greater efficacy than ospemifene 30 mg. Safety was also evaluated in these phase 3 trials. There was a 5.2% increase in the incidence of hot flushes, 1.6% increase in urinary tract infections, and 0.5% increase in the incidence of headache with ospemifene over placebo. One of the phase 3 trials was a randomized, double-blind placebo-controlled trial in 826 post-menopausal women. The trial patients were required to have one or more symptom of vulvovaginal atrophy (VVA) that was moderate or severe in nature with fewer than 5% of cells that were superficial when examined by a vaginal smear and a vaginal pH of at least 5.0. This trial did not quantify relief of dyspareunia as a study outcome measure. The other phase 3 trial was conducted in 605 women aged 40 to 80, who were diagnosed with VVA, and whose worst symptom was dyspareunia.
Society and culture
Economics
In the first half of the 2013 fiscal year, Osphena generated 0.1 B yen in revenue, which is probably roughly equivalent to $974,944 U.S. dollars. When Osphena was put onto the market, it was predicted to earn $495 million in 2017.
References
External links
"Ospemifene". Drug Information Portal. U.S. National Library of Medicine. |
Repaglinide | Repaglinide is an antidiabetic drug in the class of medications known as meglitinides, and was invented in 1983. Repaglinide is an oral medication used in addition to diet and exercise for blood sugar control in type 2 diabetes mellitus. The mechanism of action of repaglinide involves promoting insulin release from β-islet cells of the pancreas; like other antidiabetic drugs, a main side effect concern is hypoglycemia. It is sold by Novo Nordisk under the name of Prandin in the United States, GlucoNorm in Canada, Surepost in Japan, Repaglinide in Egypt by EIPICO, and NovoNorm elsewhere. In Japan it is produced by Dainippon Sumitomo Pharma.
Medical uses
Repaglinide is an oral medication used in addition to diet and exercise for blood sugar control in type 2 diabetes mellitus.
Contraindications
Repaglinide is contraindicated in people with:
Diabetic ketoacidosis, with or without coma
Type 1 diabetes
Co-administration with gemfibrozil
Known hypersensitivity to drug or inactive ingredients
Adverse events
Common adverse events include:Metabolic
Hypoglycemia (31%)Respiratory
Upper respiratory infection (16%)
Sinusitis (6%)
Rhinitis (3%)Gastrointestinal
Nausea (5%)
Diarrhea (5%)
Constipation (3%)
Vomiting (3%)Musculoskeletal
Arthralgia (6%)
Back Pain (5%)Other
Headache (11%)
Paresthesia (3%)Serious adverse events include:
Cardiac ischemia (2%)
Angina (1.8%)
Deaths due to cardiovascular events (0.5%)
Special populations
Pregnancy category C: safety in pregnant women has not been established. Data is limited, and there is only one case report that notes no complications with the use of repaglinide during pregnancy.Caution should be taken in people with liver disease and decreased kidney function when using this medication.
Drug interactions
Repaglinide is a major substrate of CYP3A4 and should not be administered concomitantly with gemfibrozil, clarithromycin or azole antifungals such as itraconazole or ketoconazole. Administration of both repaglinide and one or more of these drugs results in an increase in plasma concentration of repaglinide and may lead to hypoglycemia. Co-administration of repaglinide and clopidogrel (a CYP2C8 inhibitor) may lead to a significant decrease in blood glucose levels due to a drug-drug interaction. In fact, using these drugs together for even one day can cause repaglinide levels to increase over 5-fold...and may lead to significant hypoglycemia.
Repaglinide should not be combined with sulfonylurea, because they have the same mechanism of action.
Pharmacology
Mechanism of action
Repaglinide lowers blood glucose by stimulating the release of insulin from the beta islet cells of the pancreas. It achieves this by closing ATP-dependent potassium channels in the membrane of the beta cells. This depolarizes the beta cells, opening the cells calcium channels, and the resulting calcium influx induces insulin secretion.
Pharmacokinetics
Absorption: repaglinide has a 56% bioavailability when absorbed from the gastrointestinal tract. Bioavailability is reduced when taken with food; the maximum concentration decreases by 20%.
Distribution: The protein binding of repalglinide to albumin is greater than 98%.
Metabolism: repaglinide is primarily metabolized by the liver - specifically CYP450 2C8 and 3A4 - and to a lesser extent via glucuronidation. Metabolites of repaglinide are inactive and do not display glucose-lowering effects.
Excretion: repaglinide is 90% excreted in the feces and 8% in the urine. 0.1% is cleared unchanged in the urine. Less than 2% is unchanged in the feces.
History
Precursor drugs to repaglinide were invented in late 1983 by scientists at Dr Karl Thomae GmbH, a German drug manufacturer located at Biberach an der Riß in southern Germany which was acquired by Boehringer Ingelheim in 1990. The drug that became repaglinide was later licensed by Boehringer to Novo Nordisk, which filed an Investigational New Drug application for the compound with the Food and Drug Administration (FDA) in April 1992. Novo Nordisk filed its New Drug Application (NDA) for Prandin in July 1997 and it was quickly approved, gaining FDA approval in December 1997. The drug was the first of the meglitinide class. It was branded Prandin because its quick onset and short duration of action concentrates its effect around meal time (the prandium was the Roman meal which is comparable to the modern lunch).
Intellectual property
After several attempts to file for U.S. patent protection, a filing was made in March 1990 which eventually became U.S. Patents 5,216,167 (June 1993), 5,312,924 (May 1994) and 6,143,769 (November 2000). After filing its NDA for repaglinide in 1997, Novo Nordisk applied for patent extension under the Hatch-Waxman Act. This process, called patent term restoration, allows drug patents to be extended based on the time that a drug spent in clinical trials and in the approval process. Previously it had been decided by the U.S. Patent and Trademark Office that the expiration date of U.S. Patents 5,216,167 and 5,312,924 would be 5 September 2006. In February 2001 Prandins patent life was extended to 14 March 2009 in response to Novo Nordisks patent term restoration application, with U.S. Patent 5,216,167 having been reissued as RE37035.Prior to the end of repaglinides patent term, Novo Nordisk obtained a new patent, U.S. Patent 6,677,358 (January 2004), covering the combination therapy of repaglinide together with the generic anti-diabetic drug metformin. This new patent was due to expire June 2018. In January 2011, a federal court ruled Novo Nordisks new patent invalid on the grounds of obviousness, and unenforceable on the grounds of inequitable conduct on the part of Novo Nordisks patent attorneys.
References
External links
"Repaglinide". Drug Information Portal. U.S. National Library of Medicine. |
Remifentanil | Remifentanil is a potent, short-acting synthetic opioid analgesic drug. It is given to patients during surgery to relieve pain and as an adjunct to an anaesthetic. Remifentanil is used for sedation as well as combined with other medications for use in general anesthesia. The use of remifentanil has made possible the use of high-dose opioid and low-dose hypnotic anesthesia, due to synergism between remifentanil and various hypnotic drugs and volatile anesthetics.
Clinical use
Remifentanil is used as an opioid analgesic that has a rapid onset and rapid recovery time. It has been used effectively during craniotomies, spinal surgery, cardiac surgery, and gastric bypass surgery. While opiates function similarly, with respect to analgesia, the pharmacokinetics of remifentanil allows for quicker post-operative recovery.
Administration
It is administered in the form remifentanil hydrochloride and in adults is given as an intravenous infusion in doses ranging from 0.1 microgram per kilogram per minute to 0.5 (µg/kg)/min. Children may require higher infusion rates (up to 1.0 (µg/kg)/min). The clinically useful infusion rates are 0.025–0.1 (µg/kg)/min for sedation (rates adjusted to age of patient, severity of their illness and invasiveness of surgical procedure). Small amounts of other sedative medications are usually co-administered with remifentanil to produce sedation. Clinically useful infusion rates in general anesthesia vary but are usually 0.1–1 (µg/kg)/min.Remifentanil can be administered as part of an anesthesia technique called TIVA (total intravenous anesthesia) using computer controlled infusion pumps in a process called target controlled infusion (TCI). A target plasma concentration is entered as ng/ml into the pump, which calculates its infusion rate according to patient factors like age and weight. Induction levels of 40 ng/ml are commonly used, but it generally varies between 3–8 ng/ml. For certain surgical procedures that produce particularly strong stimuli a level of up to 15 ng/ml might be needed. The relatively short context-sensitive half-life of remifentanil allows the desired blood plasma level to be achieved quickly, and also for the same reason, recovery occurs quickly. This allows remifentanil to be used in unique circumstances such as cesarean section.Remifentanils short context-sensitive half-life makes it ideal for intense pain of short duration. As such, it has been used for analgesia in labor successfully; however, it is not as effective as epidural analgesia.In combination with propofol, remifentanil is used for anesthesia of patients undergoing electroconvulsive therapy.
Metabolism
Remifentanil is considered a metabolic soft drug, one that is rapidly metabolized to an inactive form. Unlike other synthetic opioids which are hepatically metabolized, remifentanil has an ester linkage which undergoes rapid hydrolysis by non-specific tissue and plasma esterases. This means that accumulation does not occur with remifentanil and its context-sensitive half-life remains at 4 minutes after a 4-hour infusion.
Remifentanil is metabolized to a compound (remifentanil acid) which has 1/4600th the potency of the parent compound.Due to its quick metabolism and short effects, remifentanil has opened up new possibilities in anesthesia. When remifentanil is used together with a hypnotic (i.e. one that produces sleep) it can be used in relative high doses. This is because remifentanil will be rapidly eliminated from the blood plasma on termination of the remifentanil infusion, hence the effects of the drug will quickly dissipate even after very long infusions. Owing to synergism between remifentanil and hypnotic drugs (such as propofol) the dose of the hypnotic can be substantially reduced. This leads often to more hemodynamic stability during surgery and a quicker post-operative recovery time.
Side-effects
Remifentanil is a specific μ-receptor agonist. Hence, it causes a reduction in sympathetic nervous system tone, respiratory depression and analgesia. The drugs effects include a dose-dependent decrease in heart rate and arterial pressure and respiratory rate and tidal volume. Muscle rigidity is sometimes noted.
The most common side effects reported by patients receiving this medication are a sense of extreme "dizziness" (often short lived, a common side effect of other fast-acting synthetic phenylpiperidine narcotics such as fentanyl and alfentanil) and intense itching (pruritus), often around the face. These side effects are often controlled by either altering the administered dose (decreasing or in some cases, increasing the dose) or by administering other sedatives that allow the patient to tolerate or lose awareness of the side effect.
Because pruritus is due to excessive serum histamine levels, antihistamines such as diphenhydramine (Benadryl) are often co-administered. This is done with care, however, as excessive sedation may occur.
Nausea can occur as a side effect of remifentanil, however, it is usually transient in nature due to the drugs short half-life which rapidly removes it from the patients circulation once the infusion is terminated.
Potency
Comparing its analgesia-sedation effect in ventilated patients, remifentanil may be superior to morphine but not to fentanyl.
Circumventing naltrexone
Remifentanil has been used with some success to circumvent naltrexone in patients who are in need of pain management.
Abuse potential
Remifentanil, being a μ-receptor agonist, functions like other μ-receptor agonists, such as morphine and codeine; it can cause euphoria and has the potential for abuse. However, due to its rapid metabolism and short-acting half-life the likelihood of abuse is quite low. Nevertheless, there have been some documentations of remifentanil abuse.
Development and marketing
Prior to the development of remifentanil, most short-acting hypnotics and amnestics faced issues with prolonged use, where accumulation would result in unfavorable lingering effects during post-operative recovery. Remifentanil was designed to serve as a strong anesthetic with an ultra-short and predictable duration that would not have accumulation issues.Remifentanil was patented by Glaxo Wellcome Inc. and was FDA approved on July 12, 1996. Its patent ended on the 10th of September 2017.
Pricing for Ultiva
1 mg vial - US$30.19
2 mg vial - US$57.20
5 mg vial - US$118.15
Regulation
In Hong Kong, remifentanil is regulated under Schedule 1 of Hong Kongs Chapter 134 Dangerous Drugs Ordinance. It can only be used legally by health professionals and for university research purposes. The substance can be given by pharmacists under a prescription. Anyone who supplies the substance without prescription can be fined $10000 (HKD). The penalty for trafficking or manufacturing the substance is a $5,000,000 (HKD) fine and life imprisonment. Possession of the substance for consumption without license from the Department of Health is illegal with a $1,000,000 (HKD) fine and/or 7 years of jail time.
Remifentanil is a Schedule II narcotic controlled substance in the United States with a DEA ACSCN of 9739 and a 2013 annual aggregate manufacturing quota of 3750 grams, unchanged from the prior year.
References
External links
"Remifentanil". Drug Information Portal. U.S. National Library of Medicine.
"Remifentanil Hydrochloride". Drug Information Portal. U.S. National Library of Medicine. |
Oxycodone | Oxycodone, sold under the brand names Roxicodone and OxyContin (which is the extended release form) among others, is a semi-synthetic opioid medication used for treatment of moderate to severe pain. It is highly addictive and a common drug of abuse. It is usually taken by mouth, and is available in immediate-release and controlled-release formulations. Onset of pain relief typically begins within fifteen minutes and lasts for up to six hours with the immediate-release formulation. In the United Kingdom, it is available by injection. Combination products are also available with paracetamol (acetaminophen), ibuprofen, naloxone, naltrexone, and aspirin.Common side effects include euphoria, constipation, nausea, vomiting, loss of appetite, drowsiness, dizziness, itching, dry mouth, and sweating. Severe side effects may include addiction and dependence, substance abuse, irritability, depression or mania, delirium, hallucinations, hypoventilation, gastroparesis, bradycardia, and hypotension. Those allergic to codeine may also be allergic to oxycodone. Use of oxycodone in early pregnancy appears relatively safe. Opioid withdrawal may occur if rapidly stopped. Oxycodone acts by activating the μ-opioid receptor. When taken by mouth, it has roughly 1.5 times the effect of the equivalent amount of morphine.Oxycodone was first made in Germany in 1916 from thebaine. It is on the World Health Organizations List of Essential Medicines. It is available as a generic medication. In 2020, it was the 54th most commonly prescribed medication in the United States, with more than 12 million prescriptions. A number of abuse-deterrent formulations are available, such as in combination with naloxone or naltrexone.
Medical uses
Oxycodone is used for managing moderate to severe acute or chronic pain when other treatments are not sufficient. It may improve quality of life in certain types of pain. It is unclear if use in chronic pain results in improved quality of life or ongoing pain relief.Oxycodone is available as a controlled-release tablet, intended to be taken every 12 hours. A July 1996 study independent of Purdue Pharma, the drugs originator, found the controlled-release formulation had a variable duration of action ranging from 10 to 12 hours. A 2006 review found that controlled-release oxycodone is comparable to immediate-release oxycodone, morphine, and hydromorphone in management of moderate to severe cancer pain, with fewer side effects than morphine. The author concluded that the controlled-release form is a valid alternative to morphine and a first-line treatment for cancer pain. In 2014, the European Association for Palliative Care recommended oxycodone by mouth as a second-line alternative to morphine by mouth for cancer pain.In the U.S., extended-release oxycodone is approved for use in children as young as eleven years old. The approved uses are for the relief of cancer pain, trauma pain, or pain due to major surgery, in children already treated with opioids, who can tolerate at least 20 mg per day of oxycodone; this provides an alternative to Duragesic (fentanyl), the only other extended-release opioid analgesic approved for children.
Available forms
Oxycodone is available in a variety of formulations for by mouth or under the tongue:
Immediate-release oxycodone (OxyFast, OxyIR, OxyNorm, Roxicodone)
Controlled-release oxycodone (OxyContin, Xtampza ER) – 10-12 hour duration
Oxycodone tamper-resistant (OxyContin OTR)
Immediate-release oxycodone with paracetamol (acetaminophen) (Percocet, Endocet, Roxicet, Tylox)
Immediate-release oxycodone with aspirin (Endodan, Oxycodan, Percodan, Roxiprin)
Immediate-release oxycodone with ibuprofen (Combunox)
Controlled-release oxycodone with naloxone (Targin, Targiniq, Targinact) – 10-12 hour duration
Controlled-release oxycodone with naltrexone (Troxyca) – 10-12 hour duration
In the US, oxycodone is only approved for use by mouth, available as tablets and oral solutions. Parenteral formulations of oxycodone (brand name OxyNorm) are also available in other parts of the world, however, and are widely used in the European Union. In Spain, the Netherlands and the United Kingdom, oxycodone is approved for intravenous (IV) and intramuscular (IM) use. When first introduced in Germany during World War I, both IV and IM administrations of oxycodone were commonly used for postoperative pain management of Central Powers soldiers.
Side effects
Most common side effects of oxycodone include reduced sensitivity to pain, delayed gastric emptying, euphoria, anxiolysis, feelings of relaxation, and respiratory depression. Common side effects of oxycodone include constipation (23%), nausea (23%), vomiting (12%), somnolence (23%), dizziness (13%), itching (13%), dry mouth (6%), and sweating (5%). Less common side effects (experienced by less than 5% of patients) include loss of appetite, nervousness, abdominal pain, diarrhea, urinary retention, dyspnea, and hiccups. Most side effects generally become less intense over time, although issues related to constipation are likely to continue for the duration of use. Oxycodone in combination with naloxone in managed-release tablets, has been formulated to both deter abuse and reduce "opioid-induced constipation".
Dependence and withdrawal
The risk of experiencing severe withdrawal symptoms is high if a patient has become physically dependent and discontinues oxycodone abruptly. Medically, when the drug has been taken regularly over an extended period, it is withdrawn gradually rather than abruptly. People who regularly use oxycodone recreationally or at higher than prescribed doses are at even higher risk of severe withdrawal symptoms. The symptoms of oxycodone withdrawal, as with other opioids, may include "anxiety, panic attack, nausea, insomnia, muscle pain, muscle weakness, fevers, and other flu-like symptoms".Withdrawal symptoms have also been reported in newborns whose mothers had been either injecting or orally taking oxycodone during pregnancy.
Hormone levels
As with other opioids, chronic use of oxycodone (particularly with higher doses) often causes concurrent hypogonadism (low sex hormone levels).
Overdose
In high doses, overdoses, or in some persons not tolerant to opioids, oxycodone can cause shallow breathing, slowed heart rate, cold/clammy skin, pauses in breathing, low blood pressure, constricted pupils, circulatory collapse, respiratory arrest, and death.In 2011, it was the leading cause of drug-related deaths in the U.S. However, from 2012 onwards, heroin and fentanyl have become more common causes of drug-related deaths.Oxycodone overdose has also been described to cause spinal cord infarction in high doses and ischemic damage to the brain, due to prolonged hypoxia from suppressed breathing.
Interactions
Oxycodone is metabolized by the enzymes CYP3A4 and CYP2D6. Therefore, its clearance can be altered by inhibitors and inducers of these enzymes, increasing and decreasing half-life, respectively. (For lists of CYP3A4 and CYP2D6 inhibitors and inducers, see here and here, respectively.) Natural genetic variation in these enzymes can also influence the clearance of oxycodone, which may be related to the wide inter-individual variability in its half-life and potency.Ritonavir or lopinavir/ritonavir greatly increase plasma concentrations of oxycodone in healthy human volunteers due to inhibition of CYP3A4 and CYP2D6. Rifampicin greatly reduces plasma concentrations of oxycodone due to strong induction of CYP3A4. There is also a case report of fosphenytoin, a CYP3A4 inducer, dramatically reducing the analgesic effects of oxycodone in a chronic pain patient. Dosage or medication adjustments may be necessary in each case.
Pharmacology
Pharmacodynamics
Oxycodone, a semi-synthetic opioid, is a highly selective full agonist of the μ-opioid receptor (MOR). This is the main biological target of the endogenous opioid neuropeptide β-endorphin. Oxycodone has low affinity for the δ-opioid receptor (DOR) and the κ-opioid receptor (KOR), where it is an agonist similarly. After oxycodone binds to the MOR, a G protein-complex is released, which inhibits the release of neurotransmitters by the cell by decreasing the amount of cAMP produced, closing calcium channels, and opening potassium channels. Opioids like oxycodone are thought to produce their analgesic effects via activation of the MOR in the midbrain periaqueductal gray (PAG) and rostral ventromedial medulla (RVM). Conversely, they are thought to produce reward and addiction via activation of the MOR in the mesolimbic reward pathway, including in the ventral tegmental area, nucleus accumbens, and ventral pallidum. Tolerance to the analgesic and rewarding effects of opioids is complex and occurs due to receptor-level tolerance (e.g., MOR downregulation), cellular-level tolerance (e.g., cAMP upregulation), and system-level tolerance (e.g., neural adaptation due to induction of ΔFosB expression).Taken orally, 20 mg of immediate-release oxycodone is considered to be equivalent in analgesic effect to 30 mg of morphine, while extended release oxycodone is considered to be twice as potent as oral morphine.Similarly to most other opioids, oxycodone increases prolactin secretion, but its influence on testosterone levels is unknown. Unlike morphine, oxycodone lacks immunosuppressive activity (measured by natural killer cell activity and interleukin 2 production in vitro); the clinical relevance of this has not been clarified.
Active metabolites
A few of the metabolites of oxycodone have also been found to be active as MOR agonists, some of which notably have much higher affinity for (as well as higher efficacy at) the MOR in comparison. Oxymorphone possesses 3- to 5-fold higher affinity for the MOR than does oxycodone, while noroxycodone and noroxymorphone possess one-third of and 3-fold higher affinity for the MOR, respectively, and MOR activation is 5- to 10-fold less with noroxycodone but 2-fold higher with noroxymorphone relative to oxycodone. Noroxycodone, noroxymorphone, and oxymorphone also have longer biological half-lives than oxycodone.
However, despite the greater in vitro activity of some of its metabolites, it has been determined that oxycodone itself is responsible for 83.0% and 94.8% of its analgesic effect following oral and intravenous administration, respectively. Oxymorphone plays only a minor role, being responsible for 15.8% and 4.5% of the analgesic effect of oxycodone after oral and intravenous administration, respectively. Although the CYP2D6 genotype and the route of administration result in differential rates of oxymorphone formation, the unchanged parent compound remains the major contributor to the overall analgesic effect of oxycodone. In contrast to oxycodone and oxymorphone, noroxycodone and noroxymorphone, while also potent MOR agonists, poorly cross the blood–brain barrier into the central nervous system, and for this reason are only minimally analgesic in comparison.
κ-opioid receptor
In 1997, a group of Australian researchers proposed (based on a study in rats) that oxycodone acts on KORs, unlike morphine, which acts upon MORs. Further research by this group indicated the drug appears to be a high-affinity κ2b-opioid receptor agonist. However, this conclusion has been disputed, primarily on the basis that oxycodone produces effects that are typical of MOR agonists. In 2006, research by a Japanese group suggested the effect of oxycodone is mediated by different receptors in different situations. Specifically in diabetic mice, the KOR appears to be involved in the antinociceptive effects of oxycodone, while in nondiabetic mice, the μ1-opioid receptor seems to be primarily responsible for these effects.
Pharmacokinetics
Instant-release absorption profile
Oxycodone can be administered orally, intranasally, via intravenous, intramuscular, or subcutaneous injection, or rectally. The bioavailability of oral administration of oxycodone averages within a range of 60 to 87%, with rectal administration yielding the same results; intranasal varies between individuals with a mean of 46%.After a dose of conventional (immediate-release) oral oxycodone, the onset of action is 10 to 30 minutes, and peak plasma levels of the drug are attained within roughly 30 to 60 minutes; in contrast, after a dose of OxyContin (an oral controlled-release formulation), peak plasma levels of oxycodone occur in about three hours. The duration of instant-release oxycodone is 3 to 6 hours, although this can be variable depending on the individual.
Distribution
Oxycodone has a volume of distribution of 2.6L/kg, in the blood it is distributed to skeletal muscle, liver, intestinal tract, lungs, spleen, and brain. At equilibrium the unbound concentration in the brain is threefold higher than the unbound concentration in blood Conventional oral preparations start to reduce pain within 10 to 15 minutes on an empty stomach; in contrast, OxyContin starts to reduce pain within one hour.
Metabolism
The metabolism of oxycodone in humans occurs in the liver mainly via the cytochrome P450 system and is extensive (about 95%) and complex, with many minor pathways and resulting metabolites. Around 10% (range 8–14%) of a dose of oxycodone is excreted essentially unchanged (unconjugated or conjugated) in the urine. The major metabolites of oxycodone are noroxycodone (70%), noroxymorphone ("relatively high concentrations"), and oxymorphone (5%). The immediate metabolism of oxycodone in humans is as follows:
N-Demethylation to noroxycodone predominantly via CYP3A4
O-Demethylation to oxymorphone predominantly via CYP2D6
6-Ketoreduction to 6α- and 6β-oxycodol
N-Oxidation to oxycodone-N-oxideIn humans, N-demethylation of oxycodone to noroxycodone by CYP3A4 is the major metabolic pathway, accounting for 45% ± 21% of a dose of oxycodone, while O-demethylation of oxycodone into oxymorphone by CYP2D6 and 6-ketoreduction of oxycodone into 6-oxycodols represent relatively minor metabolic pathways, accounting for 11% ± 6% and 8% ± 6% of a dose of oxycodone, respectively.Several of the immediate metabolites of oxycodone are subsequently conjugated with glucuronic acid and excreted in the urine. 6α-Oxycodol and 6β-oxycodol are further metabolized by N-demethylation to nor-6α-oxycodol and nor-6β-oxycodol, respectively, and by N-oxidation to 6α-oxycodol-N-oxide and 6β-oxycodol-N-oxide (which can subsequently be glucuronidated as well). Oxymorphone is also further metabolized, as follows:
3-Glucuronidation to oxymorphone-3-glucuronide predominantly via UGT2B7
6-Ketoreduction to 6α-oxymorphol and 6β-oxymorphol
N-Demethylation to noroxymorphoneThe first pathway of the above three accounts for 40% of the metabolism of oxymorphone, making oxymorphone-3-glucuronide the main metabolite of oxymorphone, while the latter two pathways account for less than 10% of the metabolism of oxymorphone. After N-demethylation of oxymorphone, noroxymorphone is further glucuronidated to noroxymorphone-3-glucuronide.Because oxycodone is metabolized by the cytochrome P450 system in the liver, its pharmacokinetics can be influenced by genetic polymorphisms and drug interactions concerning this system, as well as by liver function. Some people are fast metabolizers of oxycodone, while others are slow metabolizers, resulting in polymorphism-dependent alterations in relative analgesia and toxicity. While higher CYP2D6 activity increases the effects of oxycodone (owing to increased conversion into oxymorphone), higher CYP3A4 activity has the opposite effect and decreases the effects of oxycodone (owing to increased metabolism into noroxycodone and noroxymorphone). The dose of oxycodone must be reduced in patients with reduced liver function.
Elimination
The clearance of oxycodone is 0.8 L/min. Oxycodone and its metabolites are mainly excreted in urine. Therefore, oxycodone accumulates in patients with kidney impairment. Oxycodone is eliminated in the urine 10% as unchanged oxycodone, 45% ± 21% as N-demethylated metabolites (noroxycodone, noroxymorphone, noroxycodols), 11 ± 6% as O-demethylated metabolites (oxymorphone, oxymorphols), and 8% ± 6% as 6-keto-reduced metabolites (oxycodols).
Duration of action
Oxycodone has a half-life of 4.5 hours. It is available as a generic medication. The manufacturer of OxyContin, a controlled-release preparation of oxycodone, Purdue Pharma, claimed in their 1992 patent application that the duration of action of OxyContin is 12 hours in "90% of patients". It has never performed any clinical studies in which OxyContin was given at more frequent intervals. In a separate filing, Purdue claims that controlled-release oxycodone "provides pain relief in said patient for at least 12 hours after administration". However, in 2016 an investigation by the Los Angeles Times found that "the drug weans off hours early in many people", inducing symptoms of opiate withdrawal and intense cravings for OxyContin. One doctor, Lawrence Robbins, told journalists that over 70% of his patients would report that OxyContin would only provide 4–7 hours of relief. Doctors in the 1990s often would switch their patients to a dosing schedule of once every eight hours when they complained that the duration of action for OxyContin was too short to be taken only twice a day.Purdue strongly discouraged the practice: Purdues medical director Robert Reder wrote to one doctor in 1995 that "OxyContin has been developed for [12-hour] dosing...I request that you not use a [8-hourly] dosing regimen." Purdue repeatedly released memos to its sales representatives ordering them to remind doctors not to deviate from a 12-hour dosing schedule. One such memo read, "There is no Q8 dosing with OxyContin... [8-hour dosing] needs to be nipped in the bud. NOW!!" The journalists who covered the investigation argued that Purdue Pharma has insisted on a 12-hour duration of action for nearly all patients, despite evidence to the contrary, to protect the reputation of OxyContin as a 12-hour drug and the willingness of health insurance and managed care companies to cover OxyContin despite its high cost relative to generic opiates such as morphine.Purdue sales representatives were instructed to encourage doctors to write prescriptions for larger 12-hour doses instead of more frequent dosing. An August 1996 memo to Purdue sales representatives in Tennessee entitled "$$$$$$$$$$$$$ Its Bonus Time in the Neighborhood!" reminded the representatives that their commissions would dramatically increase if they were successful in convincing doctors to prescribe larger doses. Los Angeles Times journalists argue using interviews from opioid addiction experts that such high doses of OxyContin spaced 12 hours apart create a combination of agony during opiate withdrawal (lower lows) and a schedule of reinforcement that relieves this agony, fostering addiction.
Chemistry
Oxycodones chemical name is derived from codeine. The chemical structures are very similar, differing only in that
Oxycodone has a hydroxy group at carbon-14 (codeine has just a hydrogen in its place)
Oxycodone has a 7,8-dihydro feature. Codeine has a double bond between those two carbons; and
Oxycodone has a carbonyl group (as in ketones) in place of the hydroxyl group of codeine.It is also similar to hydrocodone, differing only in that it has a hydroxyl group at carbon-14.
Biosynthesis
In terms of biosynthesis, oxycodone has been found naturally in nectar extracts from the orchid family Epipactis helleborine; together along with another opioid: 3-{2-{3-{3-benzyloxypropyl}-3-indol, 7,8-didehydro- 4,5-epoxy-3,6-d-morphinan.Thodey et al., 2014 introduces a microbial compound manufacturing system for compounds including oxycodone. The Thodey platform produces both natural and semisynthetic opioids including this one. This system uses Saccharomyces cerevisiae with transgenes from Papaver somniferum (the opium poppy) and Pseudomonas putida to turn a thebaine input into other opiates and opioids.
Detection in biological fluids
Oxycodone and/or its major metabolites may be measured in blood or urine to monitor for clearance, non-medical use, confirm a diagnosis of poisoning, or assist in a medicolegal death investigation. Many commercial opiate screening tests cross-react appreciably with oxycodone and its metabolites, but chromatographic techniques can easily distinguish oxycodone from other opiates.
History
Martin Freund and (Jakob) Edmund Speyer of the University of Frankfurt in Germany published the first synthesis of oxycodone from thebaine in 1916. When Freund died, in 1920, Speyer wrote his obituary. Speyer, born to a Jewish family in Frankfurt am Main in 1878, became a victim of the Holocaust. He died on 5 May 1942, the second day of deportations from the Lodz Ghetto; his death was noted in the ghettos chronicle.The first clinical use of the drug was documented in 1917, the year after it was first developed. It was first introduced to the U.S. market in May 1939. In early 1928, Merck introduced a combination product containing scopolamine, oxycodone, and ephedrine under the German initials for the ingredients SEE, which was later renamed Scophedal (SCOpolamine, ePHEDrine, and eukodAL) in 1942. It was last manufactured in 1987, but can be compounded. This combination is essentially an oxycodone analogue of the morphine-based "twilight sleep", with ephedrine added to reduce circulatory and respiratory effects. The drug became known as the "Miracle Drug of the 1930s" in Continental Europe and elsewhere and it was the Wehrmachts choice for a battlefield analgesic for a time. The drug was expressly designed to provide what the patent application and package insert referred to as "very deep analgesia and profound and intense euphoria" as well as tranquillisation and anterograde amnesia useful for surgery and battlefield wounding cases. Oxycodone was allegedly chosen over other common opiates for this product because it had been shown to produce less sedation at equianalgesic doses compared to morphine, hydromorphone (Dilaudid), and hydrocodone (Dicodid).During Operation Himmler, Skophedal was also reportedly injected in massive overdose into the prisoners dressed in Polish Army uniforms in the staged incident on 1 September 1939 which opened the Second World War.The personal notes of Adolf Hitlers physician, Theodor Morell, indicate Hitler received repeated injections of "Eukodal" (oxycodone) and Scophedal, as well as Dolantin (pethidine) codeine, and morphine less frequently; oxycodone could not be obtained after late January 1945.In the early 1970s, the U.S. government classified oxycodone as a schedule II drug.Purdue Pharma, a privately held company based in Stamford, Connecticut, developed the prescription painkiller OxyContin. Upon its release in 1995, OxyContin was hailed as a medical breakthrough, a long-lasting narcotic that could help patients with moderate to severe pain. The drug became a blockbuster, and has reportedly generated some US$35 billion in revenue for Purdue.
Opioid epidemic
Oxycodone, like other opioid analgesics, tends to induce feelings of euphoria, relaxation and reduced anxiety in those who are occasional users. These effects make it one of the most commonly abused pharmaceutical drugs in the United States. Diverted oxycodone may be taken orally or ingested through insufflation; used intravenously, or the heated vapors inhaled.
United States
Oxycodone is the most widely recreationally used opioid in America. In the United States, more than 12 million people use opioid drugs recreationally. The U.S. Department of Health and Human Services estimates that about 11 million people in the U.S. consume oxycodone in a non-medical way annually.Opioids were responsible for 49,000 of the 72,000 drug overdose deaths in the U.S. in 2017. In 2007, about 42,800 emergency room visits occurred due to "episodes" involving oxycodone. In 2008, recreational use of oxycodone and hydrocodone was involved in 14,800 deaths. Some of the cases were due to overdoses of the acetaminophen component, resulting in fatal liver damage.In September 2013, the FDA released new labeling guidelines for long acting and extended release opioids requiring manufacturers to remove moderate pain as indication for use, instead stating the drug is for "pain severe enough to require daily, around-the-clock, long term opioid treatment". The updated labeling will not restrict physicians from prescribing opioids for moderate, as needed use.Reformulated OxyContin is causing some recreational users to change to heroin, which is cheaper and easier to obtain.
Lawsuits
In October 2017, The New Yorker published a story on Mortimer Sackler and Purdue Pharma regarding their ties to the production and manipulation of the oxycodone markets. The article links Raymond and Arthur Sacklers business practices with the rise of direct pharmaceutical marketing and eventually to the rise of addiction to oxycodone in the United States. The article implies that the Sackler family bears some responsibility for the opioid epidemic in the United States. In 2019, The New York Times ran a piece confirming that |
Oxycodone | Richard Sackler, the son of Raymond Sackler, told company officials in 2008 to "measure our performance by Rxs by strength, giving higher measures to higher strengths". This was verified with documents tied to a lawsuit – which was filed by the Massachusetts attorney general, Maura Healey – claiming that Purdue Pharma and members of the Sackler family knew that high doses of OxyContin over long periods would increase the risk of serious side effects, including addiction. Despite Purdue Pharmas proposal for a US$12 billion settlement of the lawsuit, the attorneys general of 23 states, including Massachusetts, rejected the settlement offer in September 2019.
Australia
The non-medical use of oxycodone existed from the early 1970s, but by 2015, 91% of a national sample of injecting drug users in Australia had reported using oxycodone, and 27% had injected it in the last six months.
Canada
Opioid-related deaths in Ontario had increased by 242% from 1969 to 2014. By 2009 in Ontario there were more deaths from oxycodone overdose than from cocaine overdose. Deaths from opioid pain relievers had increased from 13.7 deaths per million residents in 1991 to 27.2 deaths per million residents in 2004. The non-medical use of oxycodone in Canada became a problem. Areas where oxycodone is most problematic are Atlantic Canada and Ontario, where its non-medical use is prevalent in rural towns, and in many smaller to medium-sized cities. Oxycodone is also widely available across Western Canada, but methamphetamine and heroin are more serious problems in the larger cities, while oxycodone is more common in rural towns. Oxycodone is diverted through doctor shopping, prescription forgery, pharmacy theft, and overprescribing.The recent formulations of oxycodone, particularly Purdue Pharmas crush-, chew-, injection- and dissolve-resistant OxyNEO which replaced the banned OxyContin product in Canada in early 2012, have led to a decline in the recreational use of this opiate but have increased the recreational use of the more potent drug fentanyl. According to a Canadian Centre on Substance Abuse study quoted in Macleans magazine, there were at least 655 fentanyl-related deaths in Canada in a five-year period.In Alberta, the Blood Tribe police claimed that from the fall of 2014 through January 2015, oxycodone pills or a lethal fake variation referred to as Oxy 80s containing fentanyl made in illegal labs by members of organized crime were responsible for ten deaths on the Blood Reserve, which is located southwest of Lethbridge, Alberta. Province-wide, approximately 120 Albertans died from fentanyl-related overdoses in 2014.
United Kingdom
Prescriptions of Oxycodone rose in Scotland by 430% between 2002 and 2008, prompting fears of usage problems that would mirror those of the United States. The first known death due to overdose in the UK occurred in 2002.
Preventive measures
In August 2010, Purdue Pharma reformulated their long-acting oxycodone line, marketed as OxyContin, using a polymer, Intac, to make the pills more difficult to crush or dissolve in water to reduce non-medical use of OxyContin. The FDA approved relabeling the reformulated version as abuse-resistant in April 2013.Pfizer manufactures a preparation of short-acting oxycodone, marketed as Oxecta, which contains inactive ingredients, referred to as tamper-resistant Aversion Technology. It does not deter oral recreational use. Approved by the FDA in the U.S. in June 2011, the new formulation makes crushing, chewing, snorting, or injecting the opioid impractical because of a change in its chemical properties.
Legal status
Oxycodone is subject to international conventions on narcotic drugs. In addition, oxycodone is subject to national laws that differ by country. The 1931 Convention for Limiting the Manufacture and Regulating the Distribution of Narcotic Drugs of the League of Nations included oxycodone. The 1961 Single Convention on Narcotic Drugs of the United Nations, which replaced the 1931 convention, categorized oxycodone in Schedule I. Global restrictions on Schedule I drugs include "limit[ing] exclusively to medical and scientific purposes the production, manufacture, export, import, distribution of, trade in, use and possession of" these drugs; "requir[ing] medical prescriptions for the supply or dispensation of [these] drugs to individuals"; and "prevent[ing] the accumulation" of quantities of these drugs "in excess of those required for the normal conduct of business".
Australia
Oxycodone is in Schedule I (derived from the Single Convention on Narcotic Drugs) of the Commonwealths Narcotic Drugs Act 1967. In addition, it is in Schedule 8 of the Australian Standard for the Uniform Scheduling of Drugs and Poisons ("Poisons Standard"), meaning it is a "controlled drug... which should be available for use but require[s] restriction of manufacture, supply, distribution, possession and use to reduce abuse, misuse and physical or psychological dependence".
Canada
Oxycodone is a controlled substance under Schedule I of the Controlled Drugs and Substances Act (CDSA).
Canadian legislative changes
In February 2012, Ontario passed legislation to allow the expansion of an already existing drug-tracking system for publicly funded drugs to include those that are privately insured. This database will function to identify and monitor patients attempts to seek prescriptions from multiple doctors or retrieve them from multiple pharmacies. Other provinces have proposed similar legislation, while some, such as Nova Scotia, have legislation already in effect for monitoring prescription drug use. These changes have coincided with other changes in Ontarios legislation to target the misuse of painkillers and high addiction rates to drugs such as oxycodone. As of 29 February 2012, Ontario passed legislation delisting oxycodone from the provinces public drug benefit program. This was a first for any province to delist a drug based on addictive properties. The new law prohibits prescriptions for OxyNeo except to certain patients under the Exceptional Access Program including palliative care and in other extenuating circumstances. Patients already prescribed oxycodone will receive coverage for an additional year for OxyNeo, and after that, it will be disallowed unless designated under the exceptional access program.Much of the legislative activity has stemmed from Purdue Pharmas decision in 2011 to begin a modification of Oxycontins composition to make it more difficult to crush for snorting or injecting. The new formulation, OxyNeo, is intended to be preventive in this regard and retain its effectiveness as a painkiller. Since introducing its Narcotics Safety and Awareness Act, Ontario has committed to focusing on drug addiction, particularly in the monitoring and identification of problem opioid prescriptions, as well as the education of patients, doctors, and pharmacists. This Act, introduced in 2010, commits to the establishment of a unified database to fulfil this intention. Both the public and medical community have received the legislation positively, though concerns about the ramifications of legal changes have been expressed. Because laws are largely provincially regulated, many speculate a national strategy is needed to prevent smuggling across provincial borders from jurisdictions with looser restrictions.In 2015, Purdue Pharmas abuse-resistant OxyNEO and six generic versions of OxyContin had been on the Canada-wide approved list for prescriptions since 2012. In June 2015, then federal Minister of Health Rona Ambrose announced that within three years all oxycodone products sold in Canada would need to be tamper-resistant. Some experts warned that the generic product manufacturers may not have the technology to achieve that goal, possibly giving Purdue Pharma a monopoly on this opiate.
Canadian lawsuits
Several class-action suits across Canada have been launched against the Purdue group of companies and affiliates. Claimants argue the pharmaceutical manufacturers did not meet a standard of care and were negligent in doing so. These lawsuits reference earlier judgments in the United States, which held that Purdue was liable for wrongful marketing practices and misbranding. Since 2007, the Purdue companies have paid over CAN$650 million in settling litigation or facing criminal fines.
Germany
The drug is in Appendix III of the Narcotics Act (Betäubungsmittelgesetz or BtMG). The law allows only physicians, dentists, and veterinarians to prescribe oxycodone and the federal government to regulate the prescriptions (e.g., by requiring reporting).
Hong Kong
Oxycodone is regulated under Part I of Schedule 1 of Hong Kongs Chapter 134 Dangerous Drugs Ordinance.
Japan
Oxycodone is a restricted drug in Japan. Its import and export are strictly restricted to specially designated organizations having a prior permit to import it. In a high-profile case an American who was a top Toyota executive living in Tokyo, who claimed to be unaware of the law, was arrested for importing oxycodone into Japan.
Singapore
Oxycodone is listed as a Class A drug in the Misuse of Drugs Act of Singapore, which means offences concerning the drug attract the most severe level of punishment. A conviction for unauthorized manufacture of the drug attracts a minimum sentence of 10 years of imprisonment and corporal punishment of 5 strokes of the cane, and a maximum sentence of life imprisonment or 30 years of imprisonment and 15 strokes of the cane. The minimum and maximum penalties for unauthorized trafficking in the drug are respectively 5 years of imprisonment and 5 strokes of the cane, and 20 years of imprisonment and 15 strokes of the cane.
United Kingdom
Oxycodone is a Class A drug under the Misuse of Drugs Act 1971. For Class A drugs, which are "considered to be the most likely to cause harm", possession without a prescription is punishable by up to seven years in prison, an unlimited fine, or both. Dealing of the drug illegally is punishable by up to life imprisonment, an unlimited fine, or both. In addition, oxycodone is a Schedule 2 drug per the Misuse of Drugs Regulations 2001 which "provide certain exemptions from the provisions of the Misuse of Drugs Act 1971".
United States
Under the Controlled Substances Act, oxycodone is a Schedule II controlled substance whether by itself or part of a multi-ingredient medication. The DEA lists oxycodone both for sale and for use in manufacturing other opioids as ACSCN 9143 and in 2013 approved the following annual aggregate manufacturing quotas: 131.5 metric tons for sale, down from 153.75 in 2012, and 10.25 metric tons for conversion, unchanged from the previous year. In 2020, oxycodone possession was decriminalized in the U.S. state of Oregon.
Economics
The International Narcotics Control Board estimated 11.5 short tons (10.4 t) of oxycodone were manufactured worldwide in 1998; by 2007 this figure had grown to 75.2 short tons (68.2 t). United States accounted for 82% of consumption in 2007 at 51.6 short tons (46.8 t). Canada, Germany, Australia, and France combined accounted for 13% of consumption in 2007. In 2010, 1.3 short tons (1.2 t) of oxycodone were illegally manufactured using a fake pill imprint. This accounted for 0.8% of consumption. These illicit tablets were later seized by the U.S. Drug Enforcement Administration, according to the International Narcotics Control Board. The board also reported 122.5 short tons (111.1 t) manufactured in 2010. This number had decreased from a record high of 135.9 short tons (123.3 t) in 2009.
Names
Expanded expressions for the compound oxycodone in the academic literature include "dihydrohydroxycodeinone", "Eucodal", "Eukodal", "14-hydroxydihydrocodeinone", and "Nucodan". In a UNESCO convention, the translations of "oxycodone" are oxycodon (Dutch), oxycodone (French), oxicodona (Spanish), الأوكسيكودون (Arabic), 羟考酮 (Chinese), and оксикодон (Russian). The word "oxycodone" should not be confused with "oxandrolone", "oxazepam", "oxybutynin", "oxytocin", or "Roxanol".Other brand names include Longtec and Shortec.
See also
Sackler family
Medical-industrial complex
References
Further reading
Coluzzi F, Mattia C (July–August 2005). "Oxycodone. Pharmacological profile and clinical data in chronic pain management" (PDF). Minerva Anestesiologica. 71 (7–8): 451–460. PMID 16012419. Archived from the original (PDF) on 9 March 2006.
External links
"Oxycodone". Drug Information Portal. U.S. National Library of Medicine.
"Oxycodone hydrochloride". Drug Information Portal. U.S. National Library of Medicine. |
Revefenacin | Revefenacin, sold under the brand name Yupelri, is a medication for the treatment of chronic obstructive pulmonary disease (COPD). It was approved for use in the United States in 2018. It was developed by Theravance Biopharma and is marketed by Mylan. Revefenacin is formulated as a solution that is nebulized and inhaled.Revefenacin is a bronchodilator that exerts its effect as a long-acting muscarinic antagonist.
References
External links
"Revefenacin". Drug Information Portal. U.S. National Library of Medicine. |
Cefepime | Cefepime is a fourth-generation cephalosporin antibiotic. Cefepime has an extended spectrum of activity against Gram-positive and Gram-negative bacteria, with greater activity against both types of organism than third-generation agents. A 2007 meta-analysis suggested when data of trials were combined, mortality was increased in people treated with cefepime compared with other β-lactam antibiotics. In response, the U.S. Food and Drug Administration (FDA) performed their own meta-analysis which found no mortality difference.Cefepime was patented in 1982 by Bristol-Myers Squibb and approved for medical use in 1994. It is available as a generic drug and sold under a variety of trade names worldwide.It was removed from the World Health Organizations List of Essential Medicines in 2019.
Medical use
Cefepime is usually reserved to treat moderate to severe nosocomial pneumonia, infections caused by multiple drug-resistant microorganisms (e.g. Pseudomonas aeruginosa) and empirical treatment of febrile neutropenia.Cefepime has good activity against important pathogens including Pseudomonas aeruginosa, Staphylococcus aureus, and multiple drug-resistant Streptococcus pneumoniae. A particular strength is its activity against Enterobacteriaceae. Whereas other cephalosporins are degraded by many plasmid- and chromosome-mediated beta-lactamases, cefepime is stable and is a front-line agent when infection with Enterobacteriaceae is known or suspected.
Spectrum of bacterial susceptibility
Cefepime is a broad-spectrum cephalosporin antibiotic and has been used to treat bacteria responsible for causing pneumonia and infections of the skin and urinary tract. Some of these bacteria include Pseudomonas, Escherichia, and Streptococcus species. The following represents MIC susceptibility data for a few medically significant microorganisms:
Escherichia coli: ≤0.007 – 128 μg/ml
Pseudomonas aeruginosa: 0.06 – >256 μg/ml
Streptococcus pneumoniae: ≤0.007 – >8 μg/ml
Chemistry
The combination of the syn-configuration of the methoxy imino moiety and the aminothiazole moiety confers extra stability to β-lactamase enzymes produced by many bacteria. The N-methyl pyrrolidine moiety increases penetration into Gram-negative bacteria. These factors increase the activity of cefepime against otherwise resistant organisms including Pseudomonas aeruginosa and Staphylococcus aureus.
Trade names
Following expiration of the Bristol-Myers Squibb patent, cefepime became available as a generic and is now marketed by numerous companies worldwide under tradenames including Neopime (Neomed), Maxipime, Cepimax, Cepimex, and Axepim.
References
External links
"Cefepime". Drug Information Portal. U.S. National Library of Medicine. |
Metirosine | Metirosine (INN and BAN; α-Methyltyrosine, Metyrosine USAN, AMPT) is an antihypertensive drug. It inhibits the enzyme tyrosine hydroxylase and, therefore, catecholamine synthesis, which, as a consequence, depletes the levels of the catecholamines dopamine, adrenaline and noradrenaline in the body.
It is available as a generic medication.
Clinical use
Metirosine has been shown to suppress catecholamine synthesis and alleviate symptoms related to catecholamine excess, including hypertension, headache, tachycardia, constipation, and tremor. Metirosine is primarily used to reduce these symptoms in patients with pheochromocytoma. It is contraindicated for the treatment of essential hypertension.
Metirosine is used as an off-label treatment for DiGeorge syndrome.Metirosine is used in scientific research to investigate the effects of catecholamine depletion on behavior. There is evidence that catecholamine depletion causes an increase in sleepiness that is more pronounced than sleep deprivation, and that the fatigue lingers after the drug is discontinued. Negative mood is also a reported side effect of catecholamine depletion, although this is reported less consistently than sleepiness.
See also
p-Chlorophenylalanine
References
External links
"Metyrosine". Drug Information Portal. U.S. National Library of Medicine. |
Levothyroxine | Levothyroxine, also known as L-thyroxine, is a manufactured form of the thyroid hormone thyroxine (T4). It is used to treat thyroid hormone deficiency (hypothyroidism), including and a severe form known as myxedema coma. It may also be used to treat and prevent certain types of thyroid tumors. It is not indicated for weight loss. Levothyroxine is taken by mouth or given by intravenous injection. Maximum effect from a specific dose can take up to six weeks to occur.Side effects from excessive doses include weight loss, trouble tolerating heat, sweating, anxiety, trouble sleeping, tremor, and fast heart rate. Use is not recommended in people who have had a recent heart attack. Use during pregnancy has been found to be safe. Dosing should be based on regular measurements of thyroid-stimulating hormone (TSH) and T4 levels in the blood. Much of the effect of levothyroxine is following its conversion to triiodothyronine (T3).Levothyroxine was first made in 1927. It is on the World Health Organizations List of Essential Medicines. Levothyroxine is available as a generic medication. In 2020, it was the second most commonly prescribed medication in the United States, with more than 98 million prescriptions.
Medical use
Levothyroxine is typically used to treat hypothyroidism, and is the treatment of choice for people with hypothyroidism who often require lifelong thyroid hormone therapy.It may also be used to treat goiter via its ability to lower thyroid-stimulating hormone (TSH), which is considered goiter-inducing. Levothyroxine is also used as interventional therapy in people with nodular thyroid disease or thyroid cancer to suppress TSH secretion. A subset of people with hypothyroidism treated with an appropriate dose of levothyroxine will describe continuing symptoms despite TSH levels in the normal range. In these people, further laboratory and clinical evaluation is warranted, as they may have another cause for their symptoms. Furthermore, reviewing their medications and possible dietary supplements is important, as several medications can affect thyroid hormone levels.Levothyroxine is also used to treat subclinical hypothyroidism, which is defined by an elevated TSH level and a normal-range free T4 level without symptoms. Such people may be asymptomatic and whether they should be treated is controversial. One benefit of treating this population with levothyroxine therapy is preventing development of hypothyroidism. As such, treatment should be taken into account for patients with initial TSH levels above 10 mIU/L, people with elevated thyroid peroxidase antibody titers, people with symptoms of hypothyroidism and TSH levels of 5–10 mIU/L, and women who are pregnant or want to become pregnant. Oral dosing for patients with subclinical hypothyroidism is 1 μg/kg/day.It is also used to treat myxedema coma, which is a severe form of hypothyroidism characterized by mental status changes and hypothermia. As it is a medical emergency with a high mortality rate, it should be treated in the intensive-care unit with thyroid hormone replacement and aggressive management of individual organ system complications.
Dosages vary according to the age groups and the individual condition of the person, body weight, and compliance to the medication and diet. Other predictors of the required dosage are sex, body mass index, deiodinase activity (SPINA-GD), and etiology of hypothyroidism. Annual or semiannual clinical evaluations and TSH monitoring are appropriate after dosing has been established. Levothyroxine is taken on an empty stomach about half an hour to an hour before meals. As such, thyroid replacement therapy is usually taken 30 minutes prior to eating in the morning. For patients with trouble taking levothyroxine in the morning, bedtime dosing is effective, as well. A study in 2015 showed greater efficacy of levothyroxine when taken at bedtime. Doses of levothyroxine that normalize serum TSH may not normalize abnormal levels of LDL cholesterol and total cholesterol.Poor compliance in taking the medicine is the most common cause of elevated TSH levels in people receiving appropriate doses of levothyroxine.
50 and older
For older people (over 50 years old) and people with known or suspected ischemic heart disease, levothyroxine therapy should not be initiated at the full replacement dose. Since thyroid hormone increases the hearts oxygen demand by increasing heart rate and contractility, starting at higher doses may cause an acute coronary syndrome or an abnormal heart rhythm.
Pregnancy and breastfeeding
Hypothyroidism is common among pregnant women. A nationwide cohort study showed that 1.39% of all pregnant women in 2010 in Denmark received a prescription of levothyroxine during pregnancy. According to the U.S. Food and Drug Administration pregnancy categories, levothyroxine has been assigned category A. Given that no increased risk of congenital abnormalities has been demonstrated in pregnant women taking levothyroxine, therapy should be continued during pregnancy. Furthermore, therapy should be immediately administered to women diagnosed with hypothyroidism during pregnancy, as hypothyroidism is associated with a higher rate of complications, such as spontaneous abortion, preeclampsia, and premature birth.Thyroid hormone requirements increase during and last throughout pregnancy. As such, pregnant women are recommended to increase to nine doses of levothyroxine each week, rather than the usual seven, as soon as their pregnancy is confirmed. Repeat thyroid function tests should be done five weeks after the dosage is increased.While a minimal amount of thyroid hormones is found in breast milk, the amount does not influence infant plasma thyroid levels. Furthermore, levothyroxine was not found to cause any adverse events to the infant or mother during breastfeeding. As adequate concentrations of thyroid hormone are required to maintain normal lactation, appropriate levothyroxine doses should be administered during breastfeeding.
Children
Levothyroxine is safe and effective for children with hypothyroidism; the goal of treatment for children with hypothyroidism is to reach and preserve normal intellectual and physical development.
Contraindications
Levothyroxine is contraindicated in people with hypersensitivity to levothyroxine sodium or any component of the formulation, people with acute myocardial infarction, and people with thyrotoxicosis of any etiology. Levothyroxine is also contraindicated for people with uncorrected adrenal insufficiency, as thyroid hormones may cause an acute adrenal crisis by increasing the metabolic clearance of glucocorticoids. For oral tablets, the inability to swallow capsules is an additional contraindication.
Side effects
Adverse events are generally caused by incorrect dosing. Long-term suppression of TSH values below normal values frequently cause cardiac side effects and contribute to decreases in bone mineral density (low TSH levels are also well known to contribute to osteoporosis).Too high a dose of levothyroxine causes hyperthyroidism. Overdose can result in heart palpitations, abdominal pain, nausea, anxiousness, confusion, agitation, insomnia, weight loss, and increased appetite. Allergic reactions to the drug are characterized by symptoms such as difficulty breathing, shortness of breath, or swelling of the face and tongue. Acute overdose may cause fever, hypoglycemia, heart failure, coma, and unrecognized adrenal insufficiency.
Acute massive overdose may be life-threatening; treatment should be symptomatic and supportive. Massive overdose can be associated with increased sympathetic activity, thus may require treatment with beta-blockers.The effects of overdosing appear 6 hours to 11 days after ingestion.
Interactions
Many foods and other substances can interfere with absorption of thyroxine. Substances that reduce absorption are aluminium- and magnesium-containing antacids, simethicone, sucralfate, cholestyramine, colestipol, and polystyrene sulfonate. Sevelamer with calcium carbonate may decrease the bioavailability of levothyroxine. Grapefruit juice may delay the absorption of levothyroxine, but based on a study of 10 healthy people aged 20–30 (eight men, two women), it may not have a significant effect on bioavailability in young adults. A study of eight women suggested that coffee may interfere with the intestinal absorption of levothyroxine, though at a level less than eating bran. Certain other substances can cause adverse effects that may be severe. Combination of levothyroxine with ketamine may cause hypertension and tachycardia; and tricyclic and tetracyclic antidepressants increase its toxicity. Lithium, though, can cause hyperthyroidism (but most often hypothyroidism) by affecting iodine metabolism of the thyroid itself, thus inhibiting synthetic levothyroxine, as well. Soy, walnuts, fiber, calcium supplements, and iron supplements can also adversely affect absorption. A study found that cows milk reduces levothyroxine absorption.To minimize interactions, a manufacturer of levothyroxine recommends after taking it, waiting 30 minutes to one hour before eating or drinking anything that is not water. They further recommend to take it in the morning on an empty stomach.
Mechanism of action
Levothyroxine is a synthetic form of thyroxine (T4), an endogenous hormone secreted by the thyroid gland, which is converted to its active metabolite, L-triiodothyronine (T3). T4 and T3 bind to thyroid receptor proteins in the cell nucleus and cause metabolic effects through the control of DNA transcription and protein synthesis. Like its naturally secreted counterpart, levothyroxine is a chiral compound in the L-form.
Pharmacokinetics
Absorption of orally administered levothyroxine from the gastrointestinal tract ranges from 40 to 80%, with the majority of the drug absorbed from the jejunum and upper ileum. Levothyroxine absorption is increased by fasting and decreased in certain malabsorption syndromes, by certain foods, and with age. The bioavailability of the drug is decreased by dietary fiber.Greater than 99% of circulating thyroid hormones are bound to plasma proteins including thyroxine-binding globulin, transthyretin (previously called thyroxine-binding prealbumin), and albumin. Only free hormone is metabolically active.The primary pathway of thyroid hormone metabolism is through sequential deiodination. The liver is the main site of T4 deiodination, and along with the kidneys, are responsible for about 80% of circulating T3. In addition to deiodination, thyroid hormones are also excreted through the kidneys and metabolized through conjugation and glucuronidation and excreted directly into the bile and the gut, where they undergo enterohepatic recirculation.Half-life elimination is 6–7 days for people with normal lab results; 9–10 days for people with hypothyroidism; 3–4 days for people with hyperthyroidism. Thyroid hormones are primarily eliminated by the kidneys (about 80%), with urinary excretion decreasing with age. The remaining 20% of T4 is eliminated in the stool.
History
Thyroxine was first isolated in pure form in 1914, at the Mayo Clinic by Edward Calvin Kendall from extracts of hog thyroid glands. The hormone was synthesized in 1927 by British chemists Charles Robert Harington and George Barger.
Society and culture
Economics
As of 2011, levothyroxine was the second-most commonly prescribed medication in the U.S., with 23.8 million prescriptions filled each year.In 2016, it became the most commonly prescribed medication in the U.S., with more than 114 million prescriptions.
Available forms
Levothyroxine for systemic administration is available as an oral tablet, an intramuscular injection, and as a solution for intravenous infusion. Furthermore, it is available as both brand-name and generic products. While the FDA approved the use of generic levothyroxine for brand-name levothyroxine in 2004, the decision was met with disagreement by several medical associations. The American Association of Clinical Endocrinologists (AACE), the Endocrine Society, and the American Thyroid Association did not agree with the FDA that brand-name and generic formulations of levothyroxine were bioequivalent. As such, people were recommended to be started and kept on either brand-name or generic levothyroxine formulations and not changed back and forth from one to the other. For people who do switch products, their TSH and free T4 levels should be tested after six weeks to check that they are within normal range.Common brand names include Eltroxin, Euthyrox, Eutirox, Letrox, Levaxin, Lévothyrox, Levoxyl, L-thyroxine, Thyrax, and Thyrax Duotab in Europe; Thyrox and Thyronorm in South Asia; Unithroid, Eutirox, Synthroid, and Tirosint in North and South America; and Thyrin and Thyrolar in Bangladesh. Numerous generic versions also are available.The related drug dextrothyroxine (D-thyroxine) was used in the past as a treatment for hypercholesterolemia (elevated cholesterol levels), but was withdrawn due to cardiac side effects. Once weekly thyroxine (OWT) preparations are also available for clinical use. A recent meta-analysis published by Dutta et al. involving data from 4 studies (294 patients) showed that OWT is associated with less efficient control of hypothyroidism, risks of supraphysiologic elevation of thyroid hormone levels along with transient echocardiographic changes in some patients following 2-4 h of thyroxine intake. Hence it is not surprising that OWT therapy has not become popular and is very sparingly used across the globe.
References
External links
"Levothyroxine". Drug Information Portal. U.S. National Library of Medicine.
"Levothyroxine sodium". Drug Information Portal. U.S. National Library of Medicine.
"Real-world Evidence from a Narrow Therapeutic Index Product (Levothyroxine) Reflects the Therapeutic Equivalence of Generic Drug Products". U.S. Food and Drug Administration (FDA). 19 November 2020. |
Tazarotene | Tazarotene, sold under the brand name Tazorac, among others, is a third-generation prescription topical retinoid. It is primarily used for the treatment of plaque psoriasis and acne. Tazarotene is also used as a therapeutic for photoaged and photodamaged skin. Tazarotene is a member of the acetylenic class of retinoids.
Medical uses
Tazarotene is most commonly used topically to treat acne vulgaris and psoriasis. Like other topical retinoids, such as tretinoin and adapalene, tazarotene can be combined with benzoyl peroxide or an oral antibiotic, such as clindamycin or dapsone, for the treatment of acne. This results in increased efficacy compared to tazarotene monotherapy. For psoriasis, a combination therapy of tazarotene and a mid- to high-potency corticosteroid is more effective than either treatment alone.Tazarotene can also be used for the treatment of photodamaged skin. It can reduce the clinical and histological signs of photodamaged skin. The therapy is more effective when used with the daily application of sunscreen.
Pregnancy
Before 2015, tazarotene was considered a Category X drug (meaning its use was contraindicated during pregnancy) according to Food and Drug Administration (FDA) guidelines, despite demonstrating similar plasma retinoid levels as adapalene and tretinoin, which were classified as Category C drugs. Under the FDAs updated Pregnancy and Lactation Labeling Rule which eliminated the lettered pregnancy categories and came into effect in 2015, tazarotene was determined to be contraindicated in pregnancy. Because of the lack of pregnancy outcomes data for the drug, the determination was based on the teratogenic effects observed in rat and rabbit studies.
Contraindications
Tazarotene is contraindicated for use in patients who are known to be or suspected of being pregnant. Tazarotene is a known teratogen. It is also contraindicated in patients with a known hypersensitivity to any ingredient in the specific pharmaceutical formulation.
Adverse effects
Adverse effects for tazarotene include skin irritation, such as redness, itchiness, and burning. In patients with psoriasis, these adverse effects can be mitigated by a combined treatment with either mometasone furoate or fluocinonide. These effects tend to be mild to moderate, and increase in intensity as tazarotene concentration increases.
Pharmacology
Mechanism of action
Tazarotene is selective for two types of retinoic acid receptors, RAR-γ and RAR-β. Like all retinoids, it affects the ability of keratinocytes in the epidermis to proliferate and differentiate. It does so by upregulating filaggrin expression and downregulating the expression of keratinocyte transglutaminase, ornithine decarboxylase, involucrin, epidermal growth factor receptor, and various keratins.
Pharmacokinetics
More than 99% of tazarotenic acid, the active metabolite of tazarotene, in the blood binds to plasma proteins (the most predominant being albumin). The volume of distribution (VD) for tazarotene is 26.1 L/kg and the VD for tazarotenic acid is 1.97 L/kg. Tazarotene is excreted from the body via feces and urine equally, and it has an elimination half-life of 16 to 18 hours.
Synthesis
Acetylenic retinoid prodrug converted to the active metabolite, tazarotenic acid, with selective affinity for retinoic acid receptors RARβ and RARγ.
The formation of the ring system involves first alkylation of the anion from thiophenol with dimethylallyl bromide (1) to give the thioether (2). Friedel-Crafts cyclization of the olefin with the equivalent of PPA then gives the thiopyran (3). Acylation with acetyl chloride in the presence of aluminium chloride gives the methyl ketone (4). Reaction of the enolate of that ketone with diethyl chlorophosphate gives the enol phosphate 5 as a transient intermediate. This eliminates diethyl phosphite in the presence of excess base to give the corresponding acetylene 6. The anion from the reaction of the acetylene with base is then used to displace chlorine from Ethyl 6-chloronicotinate (7). This reaction affords the coupling product tazarotene (8).
== References == |
Clevidipine | Clevidipine (INN, trade name Cleviprex) is a dihydropyridine calcium channel blocker indicated for the reduction of blood pressure when oral therapy is not feasible or not desirable. Clevidipine is used IV only and practitioners titrate this drug to lower blood pressure. It has a half-life of approximately one minute. It is rapidly inactivated by esterases.
It was approved by the United States Food and Drug Administration on August 1, 2008.
Basic chemical and pharmacological properties
Clevidipine is a dihydropyridine L-type calcium channel blocker, highly selective for vascular, as opposed to myocardial, smooth muscle and, therefore, has little or no effect on myocardial contractility or cardiac conduction. It reduces mean arterial blood pressure by decreasing systemic vascular resistance. Clevidipine does not reduce cardiac filling pressure (pre-load), confirming lack of effects on the venous capacitance vessels. No increase in myocardial lactate production in coronary sinus blood has been seen, confirming the absence of myocardial ischemia due to coronary steal.
Clevidipine is rapidly metabolized by esterases in the blood and extravascular tissues. Therefore, its elimination is unlikely to be affected by hepatic (liver) or renal (kidney) dysfunction. Clevidipine does not accumulate in the body, and its clearance is independent of body weight.
The initial phase half-life is approximately 1 minute and the terminal half-life is approximately 15 minutes. Clevidipine will still be rapidly metabolized in pseudocholinesterase-deficient patients.
Clevidipine is formulated as a lipid emulsion in 20% soybean oil (Intralipid) and contains approximately 0.2 g of fat per mL (2.0 kcal/ml). Clevidipine also contains glycerin (22.5 mg/mL), purified egg yolk phospholipids (12 mg/mL), and sodium hydroxide to adjust pH. Clevidipine has a pH of 6.0–8.0
In the perioperative patient population Clevidipine produces a 4–5% reduction in systolic blood pressure within 2–4 minutes after starting a 1–2 mg/hour IV infusion.
In studies up to 72 hours of continuous infusion, there was no evidence of tolerance.
In most patients, full recovery of blood pressure is achieved in 5–15 minutes after the infusion is stopped.
Stereochemistry
Clevidipine contains a stereocenter and consists of two enantiomers. This is a racemate, ie a 1: 1 mixture of ( R ) – and the ( S ) - form:
Dosage and administration
Aseptic technique should be used when handling Cleviprex since it contains phospholipids and can support microbial growth.
Cleviprex is administered intravenously and should be titrated to achieve the desired blood pressure reduction. Blood pressure and heart rate should be monitored continually during infusion.
Cleviprex is a single use product that should not be diluted and should not be administered in the same line as other medications. Once the stopper is punctured, Cleviprex should be used within 12 hours and any unused portion remaining in the vial should be discarded. Change IV lines in accordance with hospital protocol.
An IV infusion at 1–2 mg/hour is recommended for initiation and should be titrated by doubling the dose every 90 seconds. As the blood pressure approaches goal, the infusion rate should be increased in smaller increments and titrated less frequently. The maximum infusion rate for Cleviprex is 32 mg/hour. Most patients in clinical trials were treated with doses of 16 mg/hour or less.
Because of lipid load restrictions, no more than 1000 mL (or an average of 21 mg/hour) of Cleviprex infusion is recommended per 24 hours. In clinical studies, no significant changes occurred in serum triglyceride levels in the Cleviprex treated patients. There is little experience with infusion durations beyond 72 hours at any dose. The infusion can be reduced or discontinued to achieve desired blood pressure while appropriate oral therapy is established.
Safety information
Cleviprex is intended for intravenous use. Titrate drug depending on the response of the individual patient to achieve the desired blood pressure reduction. Monitor blood pressure and heart rate continually during infusion, and then until vital signs are stable. Patients who receive prolonged Cleviprex infusions and are not transitioned to other antihypertensive therapies should be monitored for the possibility of rebound hypertension for at least 8 hours after the infusion is stopped.
In clinical trials, the safety profile of clevidipine was generally similar to sodium nitroprusside, nitroglycerin, or nicardipine in patients undergoing cardiac surgery.Cleviprex is contraindicated in patients with allergies to soybeans, soy products, eggs, or egg products; defective lipid metabolism such as pathologic hyperlipemia (rare genetic disorders characterized by abnormal triglyceride metabolism), lipoid nephrosis, or acute pancreatitis if it is accompanied by hyperlipidemia; and in patients with severe aortic stenosis.
Hypotension and reflex tachycardia are potential consequences of rapid upward titration of Cleviprex. In clinical trials, a similar increase in heart rate was observed in both Cleviprex and comparator arms. Dihydropyridine calcium channel blockers can produce negative inotropic effects and exacerbate heart failure. Heart failure patients should be monitored carefully. Cleviprex gives no protection against the effects of abrupt beta-blocker withdrawal.
Most common adverse reactions (>2%) are headache, nausea, and vomiting.
Cleviprex should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Maintain aseptic technique while handling Cleviprex. Cleviprex contains phospholipids and can support microbial growth. Do not use if contamination is suspected. Once the stopper is punctured, use or discard within 12 hours.
Drug interactions
No clinical drug interaction studies were conducted. Cleviprex does not have the potential for blocking or inducing any CYP enzymes.
Storage
Cleviprex is available in ready-to-use 50- and 100-mL glass vials at a concentration of 0.5 mg/mL of clevidipine butyrate. Vials should be refrigerated at 2-8oC (36-46 °F). Cleviprex can be stored to controlled room temperature for up to 2 months. Cleviprex is photosensitive and storage in cartons protects against photodegradation. Protection from light during administration is not required.
Phase III clinical trial results
Cleviprex has been evaluated in 6 Phase III clinical studies including the perioperative and emergency department/intensive care settings. These include ESCAPE-1, ESCAPE-2, ECLIPSE, and VELOCITY trials.
ESCAPE-1 was a double-blind, randomized, placebo-controlled efficacy trial of 105 cardiac surgery patients. In ESCAPE-1, Cleviprex had a significantly lower rate of treatment failure when compared with placebo (7.5% vs 82.7%) and a 92.5% rate of success in lowering systolic blood pressure (SBP) by ≥15%. The median time to reduce SBP ≥15% from baseline was 6 minutes.
ESCAPE-2 was a double-blind, randomized, placebo-controlled efficacy trials of 110 cardiac surgery patients. In ESCAPE-2, Cleviprex had a significantly lower rate of treatment failure when compared with placebo (8.2% vs 79.6%) and a 91.8% treatment success rate. The median time to reduce SBP ≥15% from baseline was 5.3 minutes.
The ECLIPSE trials consisted of three safety trials in which 1506 patients were randomized to receive Cleviprex, nitroglycerin, sodium nitroprusside, or nicardipine, for the treatment of hypertension associated with cardiac surgery. The incidence of death, stroke, myocardial infarction (heart attack), and renal dysfunction at 30 days did not differ significantly between the pooled Cleviprex and comparator treatment arms.
VELOCITY was an open-label trial of 126 patients with severe hypertension (BP > 180/115 mmHg) in the emergency department and intensive care unit. In VELOCITY, 104 out of 117 patients (88.9%) achieved a target SBP mean decrease of 21.1% at 30 minutes.
References
Further reading
External links
"Cleviprex Prescribing Information" (PDF). cleviprex.com. Archived from the original (PDF) on 2016-03-09.
"The Medicines Companys Cleviprex(TM) Receives FDA Approval". Press release. The Medicines Company. Retrieved 4 August 2008. |
Meclofenamic acid | Meclofenamic acid (used as meclofenamate sodium, brand name Meclomen) is a drug used for joint, muscular pain, arthritis and dysmenorrhea.
It is a member of the anthranilic acid derivatives (or fenamate) class of nonsteroidal anti-inflammatory drugs (NSAIDs) and was approved by the US FDA in 1980. Like other members of the class, it is a cyclooxygenase (COX) inhibitor, preventing the formation of prostaglandins.Scientists led by Claude Winder from Parke-Davis invented meclofenamate sodium in 1964, along with fellow members of the class, mefenamic acid in 1961 and flufenamic acid in 1963.: 718 Patents on the drug expired in 1985: 295 and several generics were introduced in the US, but as of July 2015 only Mylan still sold it.It is not widely used in humans as it has a high rate (30-60%) rate of gastrointestinal side effects.: 310
Adverse effects
In October 2020, the U.S. Food and Drug Administration (FDA) required the drug label to be updated for all nonsteroidal anti-inflammatory medications to describe the risk of kidney problems in unborn babies that result in low amniotic fluid. They recommend avoiding NSAIDs in pregnant women at 20 weeks or later in pregnancy.
Use in horses
Meclofenamic acid is sold under the trade name "Arquel" for use in horses, and is administered as an oral granule form at a dose of 2.2 mg/kg/day. It has a relatively slow onset of action, taking 36–48 hours for full effect, and is most useful for treatment of chronic musculoskeletal disease. It has been found to be beneficial for the treatment of navicular syndrome, laminitis, and osteoarthritis, in some cases having a more profound effect than the commonly used NSAID phenylbutazone. However, due to cost, it is not routinely used in practice. Toxicity due to excessive dosage is similar to that of phenylbutazone, including depression, anorexia, weight loss, edema, diarrhea, oral ulceration, and decreased hematocrit.
== References == |
Alli | Alli is a surname and a unisex given name. Notable people with the name include:
Surname
Antero Alli (born 1952), astrologer
Darogha Ubbas Alli (19th century), Indian engineer and photographer
Dele Alli (born 1996), professional footballer
Waheed Alli, Baron Alli (born 1964), British media entrepreneur and politician and notable gay Muslim
Yusuf Alli (born 1960), retired Nigerian long jumper
Given name
Male
Alli Abrew (born 1974), American football player
Alli Austria (born 1990), Filipino basketball player
Alli Muhammad (born 1968), African-American doctor
Alli NDri (born 1984), Ivorian footballer
Female
Alli Lahtinen (1926–1976), Finnish politician
Alli Mauzey, American actress
Alli Nissinen (1866–1926), Finnish educator
Alli Owens (born 1988), American racing driver
Alli Paasikivi (1879–1960), First Lady of Finland (1946–1956)
Alli Webb, American author
Fictional characters
Alli Bhandari, in the Canadian television drama Degrassi: The Next Generation, played by Melinda Shankar
See also
Ali (disambiguation)
"Alli", a brand name for the medication Orlistat
Alli (film), a 1964 Indian Tamil-language film
Alli, Iran, a village
Allie (disambiguation)
Ally (disambiguation)
Alliance of Independent Authors (ALLi) |
Diltiazem | Diltiazem, sold under the brand name Cardizem among others, is a calcium channel blocker medication used to treat high blood pressure, angina, and certain heart arrhythmias. It may also be used in hyperthyroidism if beta blockers cannot be used. It is taken by mouth or injection into a vein. When given by injection, effects typically begin within a few minutes and last a few hours.Common side effects include swelling, dizziness, headaches, and low blood pressure. Other severe side effects include an overly slow heart beat, heart failure, liver problems, and allergic reactions. Use is not recommended during pregnancy. It is unclear if use when breastfeeding is safe.Diltiazem works by relaxing the smooth muscle in the walls of arteries, resulting in them opening and allowing blood to flow more easily. Additionally, it acts on the heart to prolong the period until it can beat again. It does this by blocking the entry of calcium into the cells of the heart and blood vessels. It is a class IV antiarrhythmic.Diltiazem was approved for medical use in the United States in 1982. It is available as a generic medication. In 2019, it was the 72nd most commonly prescribed medication in the United States, with more than 10 million prescriptions. An extended release formulation is also available.
Medical uses
Diltiazem is indicated for:
Stable angina (exercise-induced) – diltiazem increases coronary blood flow and decreases myocardial oxygen consumption, secondary to decreased peripheral resistance, heart rate, and contractility.
Variant angina – it is effective owing to its direct effects on coronary dilation.
Unstable angina (preinfarction, crescendo) – diltiazem may be particularly effective if the underlying mechanism is vasospasm.
Myocardial bridge
DysmenorrheaFor supraventricular tachycardias (PSVT), diltiazem appears to be as effective as verapamil in treating re-entrant supraventricular tachycardia.Atrial fibrillation or atrial flutter is another indication. The initial bolus should be 0.25 mg/kg, intravenous (IV).
Because of its vasodilatory effects, diltiazem is useful for treating hypertension. Calcium channel blockers are well tolerated, and especially effective in treating low-renin hypertension.It is used as topical application for Anal Fissures as it promotes healing of fissures due to its vasodilatory property.
Contraindications and precautions
In congestive heart failure, patients with reduced ventricular function may not be able to counteract the inotropic and chronotropic effects of diltiazem, the result being an even higher compromise of function.
With SA node or AV conduction disturbances, the use of diltiazem should be avoided in patients with SA or AV nodal abnormalities, because of its negative chronotropic and dromotropic effects.
Low blood pressure patients, with systolic blood pressures below 90 mm Hg, should not be treated with diltiazem.
Diltiazem may paradoxically increase ventricular rate in patients with Wolff-Parkinson-White syndrome because of accessory conduction pathways.Diltiazem is relatively contraindicated in the presence of sick sinus syndrome, atrioventricular node conduction disturbances, bradycardia, impaired left ventricle function, peripheral artery occlusive disease, and chronic obstructive pulmonary disease.
Side effects
A reflex sympathetic response, caused by the peripheral dilation of vessels and the resulting drop in blood pressure, works to counteract the negative inotropic, chronotropic and dromotropic effects of diltiazem. Undesirable effects include hypotension, bradycardia, dizziness, flushing, fatigue, headaches and edema. Rare side effects are congestive heart failure, myocardial infarction, and hepatotoxicity.Diltiazem is one of the most common drugs that cause drug-induced lupus, along with hydralazine, procainamide, isoniazid, minocycline.
Drug interactions
Because of its inhibition of hepatic cytochromes CYP3A4, CYP2C9 and CYP2D6, there are a number of drug interactions. Some of the more important interactions are listed below.
Beta-blockers
Intravenous diltiazem should be used with caution with beta-blockers because, while the combination is most potent at reducing heart rate, there are rare instances of dysrhythmia and AV node block.
Quinidine
Quinidine should not be used concurrently with calcium channel blockers because of reduced clearance of both drugs and potential pharmacodynamic effects at the SA and AV nodes.
Fentanyl
Concurrent use of fentanyl with diltiazem, or any other CYP3A4 inhibitors, as these medications decrease the breakdown of fentanyl and thus increase its effects.
Mechanism
Diltiazem, also known as (2S,3S)-3-acetoxy-5-[2-(dimethylamino)ethyl]-2,3-dihydro-2-(4-methoxyphenyl)-1,5-benzothiazepin-4(5H)-one hydrochlorid has a vasodilating activity attributed to the (2S,3S)-isomer.
Diltiazem is a potent vasodilator, increasing blood flow and variably decreasing the heart rate via strong depression of A-V node conduction. It binds to the alpha-1 subunit of L-type calcium channels in a fashion somewhat similar to verapamil, another nondihydropyridine (non-DHP) calcium channel blocker. Chemically, it is based upon a 1,4-thiazepine ring, making it a benzothiazepine-type calcium channel blocker.It is a potent and mild vasodilator of coronary and peripheral vessels, respectively, which reduces peripheral resistance and afterload, though not as potent as the dihydropyridine (DHP) calcium channel blockers. This results in minimal reflexive sympathetic changes.Diltiazem has negative inotropic, chronotropic, and dromotropic effects. This means diltiazem causes a decrease in heart muscle contractility – how strong the beat is, lowering of heart rate – due to slowing of the sinoatrial node, and a slowing of conduction through the atrioventricular node – increasing the time needed for each beat. Each of these effects results in reduced oxygen consumption by the heart, reducing angina, typically unstable angina, symptoms. These effects also reduce blood pressure by causing less blood to be pumped out.
Research
Diltiazem is prescribed off-label by doctors in the US for prophylaxis of cluster headaches. Some research on diltiazem and other calcium channel antagonists in the treatment and prophylaxis of migraine is ongoing.Recent research has shown diltiazem may reduce cocaine cravings in drug-addicted rats. This is believed to be due to the effects of calcium blockers on dopaminergic and glutamatergic signaling in the brain. Diltiazem also enhances the analgesic effect of morphine in animal tests, without increasing respiratory depression, and reduces the development of tolerance.Diltiazem is also being used in the treatment of anal fissures. It can be taken orally or applied topically with increased effectiveness. When applied topically, it is made into a cream form using either vaseline or Phlojel. Phlojel absorbs the diltiazem into the problem area better than the vaseline base. It has good short-term success rates.
References
External links
"Diltiazem". Drug Information Portal. U.S. National Library of Medicine. |
Secnidazole | Secnidazole (trade names Flagentyl, Sindose, Secnil, Solosec) is a nitroimidazole anti-infective. Effectiveness in the treatment of dientamoebiasis has been reported. It has also been tested against Atopobium vaginae.In the United States, secnidazole is approved for the treatment of bacterial vaginosis and trichomoniasis in adult women.
References
== Further reading == |
Trimethoprim/sulfamethoxazole | Trimethoprim/sulfamethoxazole, sold under the brand name Bactrim among others, is a fixed-dose combination antibiotic medication used to treat a variety of bacterial infections. It consists of one part trimethoprim to five parts sulfamethoxazole. It is used to treat urinary tract infections, methicillin-resistant Staphylococcus aureus (MRSA) skin infections, travelers diarrhea, respiratory tract infections, and cholera, among others. It is used both to treat and prevent pneumocystis pneumonia and toxoplasmosis in people with HIV/AIDS and other causes of immunosuppression. It can be given by mouth or intravenously.Trimethoprim/sulfamethoxazole is on the World Health Organizations List of Essential Medicines and is also available as a generic medication. In 2019, it was the 100th most commonly prescribed medication in the United States, with more than 6 million prescriptions.
Medical uses
Pneumocystis jirovecii pneumonia
Trimethoprim/sulfamethoxazole (TMP/SMX) is the medicine most commonly used to prevent Pneumocystis jirovecii pneumonia (PCP) People who get Pneumocystis pneumonia have a medical condition that weakens their immune system, like HIV/AIDS, or take medicines (such as corticosteroids) that reduce the bodys ability to fight bacterial and viral infections. People with HIV/AIDS are less likely to get Pneumocystis pneumonia as a result of antiretroviral therapy (ART). However, Pneumocystis pneumonia is still a substantial public health problem. Most of what is scientifically known about Pneumocystis pneumonia and its treatment comes from studying people with HIV/AIDS.
Susceptibility
Organisms against which trimethoprim/sulfamethoxazole can be effective include:
The only notable nonsusceptible organisms are Pseudomonas aeruginosa, the mycoplasmae and Francisella tularensis (the causative organism of tularaemia).
Pregnancy and breast feeding
Its use during pregnancy is contraindicated, although it has been placed in Australian pregnancy category C. Its use during the first trimester (during organogenesis) and 12 weeks prior to pregnancy has been associated with an increased risk of congenital malformations, especially malformations associated with maternal folic acid deficiency (which is most likely related to the mechanism of action of co-trimoxazole) such as neural tube defects such as spina bifida, cardiovascular malformations (e.g. Ebsteins anomaly), urinary tract defects, oral clefts, and club foot in epidemiological studies. Its use later on during pregnancy also increases the risk of preterm labour (odds ratio: 1.51) and low birth weight (odds ratio: 1.67). Animal studies have yielded similarly discouraging results.It appears to be safe for use during breastfeeding as long as the baby is healthy.
Babies
Its use in those less than 2 months of age is not recommended due to the risk of adverse side effects.
Adverse effects
Common side effects include nausea, vomiting, rash, and diarrhea. Severe allergic reactions and Clostridium difficile infection may occasionally occur. Its use in pregnancy is not recommended. It appears to be safe for use during breastfeeding as long as the baby is healthy. Trimethoprim/sulfamethoxazole generally results in bacterial death. It works by blocking the making and use of folate by the microorganisms.
Contraindications
Contraindications include the following:
Interactions
Its use is advised against in people being concomitantly treated with:
Overdose
Likely signs of toxicity include:
The recommended treatment for overdose includes:
Administration of activated charcoal
Stomach pumping
General supportive measures
Haemodialysis, which is moderately effective in clearing co-trimoxazole from the plasma.
Calcium folinate treatment in cases of blood dyscrasias
Forcing oral fluidsAlkalinisation of the urine may reduce the toxicity of sulfamethoxazole, but it may increase the toxic effects of trimethoprim.
Pharmacology
The synergy between trimethoprim and sulfamethoxazole was first described in the late 1960s. Trimethoprim and sulfamethoxazole have a greater effect when given together than when given separately, because they inhibit successive steps in the folate synthesis pathway. They are given in a one-to-five ratio in their tablet formulations so that when they enter the body their concentration in the blood and tissues is roughly one-to-twenty — the exact ratio required for a peak synergistic effect between the two.Sulfamethoxazole, a sulfonamide, induces its therapeutic effects by interfering with the de novo (that is, from within the cell) synthesis of folate inside microbial organisms such as protozoa, fungi and bacteria. It does this by competing with p-aminobenzoic acid (PABA) in the biosynthesis of dihydrofolate.Trimethoprim serves as a competitive inhibitor of dihydrofolate reductase (DHFR), hence inhibiting the de novo synthesis of tetrahydrofolate, the biologically active form of folate.Tetrahydrofolate is crucial in the synthesis of purines, thymidine, and methionine which are needed for the production of DNA and proteins during bacterial replication. Thus the net effect of each of these drugs is a bacteriostatic halt in replication. When combined, TMP and SMX are bactericidal.
The effects of trimethoprim causes a backlog of dihydrofolate (DHF) and this backlog can work against the inhibitory effect the drug has on tetrahydrofolate biosynthesis. This is where the sulfamethoxazole comes in; its role is in depleting the excess DHF by preventing it from being synthesised in the first place.Co-trimoxazole was claimed to be more effective than either of its components individually in treating bacterial infections, although this was later disputed. Because it has a higher incidence of adverse effects, including allergic responses, its use has been restricted in many countries to very specific circumstances where its improved efficacy has been demonstrated. It may be effective in a variety of upper and lower respiratory tract infections, kidney and urinary tract infections, gastrointestinal tract infections, skin and wound infections, sepsis, and other infections caused by sensitive organisms. Co-trimoxazole decreases the risk of recurrence of retinochoroiditis. The global problem of advancing antimicrobial resistance has led to a renewed interest in the use of co-trimoxazole more recently.
Society and culture
Legal status
Trade names
Trimethoprim/sulfamethoxazole may be abbreviated as SXT, SMZ-TMP, TMP-SMX, TMP-SMZ, or TMP-sulfa.Co-trimoxazole (British Approved Name (BAN)) is manufactured and sold by many different companies. The following list of brand names is incomplete:
Economics
Trimethoprim/sulfamethoxazole is relatively inexpensive as of 2019.
References
External links
"Sulfamethoxazole mixture with trimethoprim". Drug Information Portal. U.S. National Library of Medicine. |
Risankizumab | Risankizumab, sold under the brand name Skyrizi, is a humanized monoclonal antibody targeting interleukin 23A (IL-23A). Risankizumab is part of a collaboration between Boehringer Ingelheim and AbbVie. Risankizumab has been approved in the European Union, the United States, and Canada for the treatment of moderate to severe plaque psoriasis in adults who are candidates for systemic therapy, and moderate to severe Crohns disease in the United States. In Japan, it is approved for treating plaque psoriasis, generalized pustular psoriasis, erythrodermic psoriasis and psoriatic arthritis in adults who have an inadequate response to conventional therapies.
Clinical trials
Psoriasis
In a phase I clinical trial, thirty-nine patients received single-dose risankizumab, eighteen of which received the drug intravenously, thirteen subcutaneously, and eight received the placebo drug. There were several instances that adverse effects occurred but in the same frequency for the placebo and the experimental groups. Four serious adverse events occurred in the risankizumab treated patients, all of which were judged not treatment related. Risankizumab was associated with clinical improvement in individuals treated with the drug, from week 2 and maintained for up to 66 weeks after treatment. At week 12 of treatment, 75%, 90%, and 100% decreases in the Psoriasis Area and Severity Index (PASI) were achieved by 87%, 58%, and 16% of risankizumab treated patients, regardless of dose, respectively, versus individuals receiving placebo. Significant correlation between treatment-associated molecular changes and PASI improvement was observed in the risankizumab treated patients.The efficacy, safety and tolerability was further investigated in a phase III program comprising four clinical trials which compared risankizumab to ustekinumab, adalimumab and placebo in the indication of plaque psoriasis. The results of these trials confirmed the efficacy and tolerability of risankizumab.
History
Risankizumab was approved by the U.S. Food and Drug Administration (FDA) for treatment of moderate-to-severe plaque psoriasis in April 2019.The FDA approved risankizumab based on evidence primarily from five clinical trials (Trial 1/NCT0202684370, Trial 2/NCT02684357, Trial 3/NCT02672852, Trial 4/ NCT02694523 and Trial 5/NCT02054481) of 1606 patients with moderate to severe plaque psoriasis. The trials were conducted in Asia, Canada, Europe, Mexico, South America, and the United States.
References
External links
"Risankizumab". Drug Information Portal. U.S. National Library of Medicine. |
Fluorouracil | Fluorouracil (5-FU), sold under the brand name Adrucil among others, is a cytotoxic chemotherapy medication used to treat cancer. By intravenous injection it is used for treatment of colorectal cancer, oesophageal cancer, stomach cancer, pancreatic cancer, breast cancer, and cervical cancer. As a cream it is used for actinic keratosis, basal cell carcinoma, and skin warts.Side effects of use by injection are common. They may include inflammation of the mouth, loss of appetite, low blood cell counts, hair loss, and inflammation of the skin. When used as a cream, irritation at the site of application usually occurs. Use of either form in pregnancy may harm the baby. Fluorouracil is in the antimetabolite and pyrimidine analog families of medications. How it works is not entirely clear but believed to involve blocking the action of thymidylate synthase and thus stopping the production of DNA.Fluorouracil was patented in 1956 and came into medical use in 1962. It is on the World Health Organizations List of Essential Medicines.
Medical uses
Fluorouracil has been given systemically for anal, breast, colorectal, oesophageal, stomach, pancreatic and skin cancers (especially head and neck cancers). It has also been given topically (on the skin) for actinic keratoses, skin cancers and Bowens disease and as eye drops for treatment of ocular surface squamous neoplasia. Other uses include ocular injections into a previously created trabeculectomy bleb to inhibit healing and cause scarring of tissue, thus allowing adequate aqueous humor flow to reduce intraocular pressure.
Contraindications
Fluorouracil is contraindicated in patients who are severely debilitated and in patients with bone marrow suppression due to either radiotherapy or chemotherapy. It is likewise contraindicated in pregnant or breastfeeding women. It should also be avoided in patients who do not have malignant illnesses.
Adverse effects
Adverse effects by frequency include:
During systemic use
Common (> 1% frequency):
Uncommon (0.1–1% frequency):
Rare (< 0.1% frequency):
Anaphylaxis
Allergic reactions
Fever without signs of infectionDiarrhea is severe and may be dose-limiting and is exacerbated by co-treatment with calcium folinate. Neutropenia tends to peak about 9–14 days after beginning treatment. Thrombocytopenia tends to peak about 7–17 days after the beginning of treatment and tends to recover about 10 days after its peak. Cardiotoxicity is a fairly common side effect, usually manifesting as angina or symptoms associated with coronary artery spasm, but about 0.55% of those receiving the drug will develop life-threatening cardiotoxicity. Life-threatening cardiotoxicity includes: arrhythmias, ventricular tachycardia and cardiac arrest, secondary to transmural ischaemia.
During topical use
Common (> 1% frequency):
Uncommon (0.1–1% frequency):
hyper- or hypopigmentation
Scarring
Neurological damage
The United States package insert warns that acute cerebellar syndrome has been observed following injection of fluorouracil and may persist after cessation of treatment. Symptoms include ataxia, nystagmus, and dysmetria.
Potential overdose
There is very little difference between the minimum effective dose and maximum tolerated dose of 5-FU, and the drug exhibits marked individual pharmacokinetic variability. Therefore, an identical dose of 5-FU may result in a therapeutic response with acceptable toxicity in some patients and unacceptable and possibly life-threatening toxicity in others. Both overdosing and underdosing are of concern with 5-FU, although several studies have shown that the majority of colorectal cancer patients treated with 5-FU are underdosed based on todays dosing standard, body surface area (BSA). The limitations of BSA-based dosing prevent oncologists from being able to accurately titer the dosage of 5-FU for the majority of individual patients, which results in sub-optimal treatment efficacy or excessive toxicity.Numerous studies have found significant relationships between concentrations of 5-FU in blood plasma and both desirable or undesirable effects on patients. Studies have also shown that dosing based on the concentration of 5-FU in plasma can greatly increase desirable outcomes while minimizing negative side effects of 5-FU therapy. One such test that has been shown to successfully monitor 5-FU plasma levels and which "may contribute to improved efficacy and safety of commonly used 5-FU-based chemotherapies" is the My5-FU test.
Interactions
Its use should be avoided in patients receiving drugs known to modulate dihydropyrimidine dehydrogenase (such as the antiviral drug sorivudine). It may also increase the INR and prothrombin times in patients on warfarin. Fluorouracils efficacy is decreased when used alongside allopurinol, which can be used to decrease fluorouracil induced stomatitis through use of allopurinol mouthwash.
Pharmacology
Pharmacogenetics
The dihydropyrimidine dehydrogenase (DPD) enzyme is responsible for the detoxifying metabolism of fluoropyrimidines, a class of drugs that includes 5-fluorouracil, capecitabine, and tegafur. Genetic variations within the DPD gene (DPYD) can lead to reduced or absent DPD activity, and individuals who are heterozygous or homozygous for these variations may have partial or complete DPD deficiency; an estimated 0.2% of individuals have complete DPD deficiency. Those with partial or complete DPD deficiency have a significantly increased risk of severe or even fatal drug toxicities when treated with fluoropyrimidines; examples of toxicities include myelosuppression, neurotoxicity and hand-foot syndrome.
Mechanism of action
5-FU acts in several ways, but principally as a thymidylate synthase (TS) inhibitor. Interrupting the action of this enzyme blocks synthesis of the pyrimidine thymidylate (dTMP), which is a nucleotide required for DNA replication. Thymidylate synthase methylates deoxyuridine monophosphate (dUMP) to form thymidine monophosphate (dTMP). Administration of 5-FU causes a scarcity in dTMP, so rapidly dividing cancerous cells undergo cell death via thymineless death. Calcium folinate provides an exogenous source of reduced folinates and hence stabilises the 5-FU-TS complex, hence enhancing 5-FUs cytotoxicity.
History
In 1954, Abraham Cantarow and Karl Paschkis found liver tumors absorbed radioactive uracil more readily than did normal liver cells. Charles Heidelberger, who had earlier found that fluorine in fluoroacetic acid inhibited a vital enzyme, asked Robert Duschinsky and Robert Schnitzer at Hoffmann-La Roche to synthesize fluorouracil. Some credit Heidelberger and Duschinsky with the discovery that 5-fluorouracil markedly inhibited tumors in mice. The original 1957 report in Nature has Heidelberger as lead author, along with N. K. Chaudhuri, Peter Danneberg, Dorothy Mooren, Louis Griesbach, Robert Duschinsky, R. J. Schnitzer, E. Pleven, and J. Scheiner.
In 1958, Anthony R. Curreri, Fred J. Ansfield, Forde A. McIver, Harry A. Waisman, and Charles Heidelberger reported the first clinical findings of 5-FUs activity in cancer in humans.
Natural analogues
In 2003, scientists isolated 5-fluorouracil derivatives, closely related compounds, from the marine sponge, Phakellia fusca collected around the Yongxing Island of the Xisha Islands in the South China Sea. This is significant because fluorine-containing organic compounds are rare in nature, and also because manmade anticancer drugs are not frequently found to have analogues in nature.
Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles.
Names
The name "fluorouracil" is the INN, USAN, USP name, and BAN. The form "5-fluorouracil" is often used; it shows that there is a fluorine atom on the 5th carbon of a uracil ring.
References
Further reading
Dean L (2016). "Fluorouracil Therapy and DPYD Genotype". In Pratt VM, McLeod HL, Rubinstein WS, et al. (eds.). Medical Genetics Summaries. National Center for Biotechnology Information (NCBI). PMID 28520376. Bookshelf ID: NBK395610.
Latchman, Jessica; Guastella, Ann; Tofthagen, Cindy (1 October 2014). "5-Fluorouracil Toxicity and Dihydropyrimidine Dehydrogenase Enzyme: Implications for Practice". Clinical Journal of Oncology Nursing. 18 (5): 581–585. doi:10.1188/14.CJON.581-585. PMC 5469441. PMID 25253112.
External links
"Fluorouracil". Drug Information Portal. U.S. National Library of Medicine.
"Fluorouracil Topical". MedlinePlus. |
Glutamine | Glutamine (symbol Gln or Q) is an α-amino acid that is used in the biosynthesis of proteins. Its side chain is similar to that of glutamic acid, except the carboxylic acid group is replaced by an amide. It is classified as a charge-neutral, polar amino acid. It is non-essential and conditionally essential in humans, meaning the body can usually synthesize sufficient amounts of it, but in some instances of stress, the bodys demand for glutamine increases, and glutamine must be obtained from the diet. It is encoded by the codons CAA and CAG.
In human blood, glutamine is the most abundant free amino acid.The dietary sources of glutamine include especially the protein-rich foods like beef, chicken, fish, dairy products, eggs, vegetables like beans, beets, cabbage, spinach, carrots, parsley, vegetable juices and also in wheat, papaya, Brussels sprouts, celery, kale and fermented foods like miso.
Functions
Glutamine plays a role in a variety of biochemical functions:
Protein synthesis, as any other of the 20 proteinogenic amino acids
Lipid synthesis, especially by cancer cells.
Regulation of acid-base balance in the kidney by producing ammonium
Cellular energy, as a source, next to glucose
Nitrogen donation for many anabolic processes, including the synthesis of purines
Carbon donation, as a source, refilling the citric acid cycle
Nontoxic transporter of ammonia in the blood circulation.
Integrity of healthy intestinal mucosa, though small randomized trials have shown no benefit in Crohn’s disease.
Roles in metabolism and cancer
Cancer cells rely on glutamine metabolism as carbon and nitrogen sources. Glutamine level in the blood serum is the highest among other amino acids and is essential for many cellular functions.
Studies have indicated the importance of glutamine in certain tumors. For example, the inhibition of glutamine metabolism was reported to prevent growth of several tumors such as breast, liver, kidney and T-cell lymphoblastic leukemia.
Precursor
Glutamine maintains redox balance by participating in glutathione synthesis and contributing to anabolic processes such as lipid synthesis by reductive carboxylation.Glutamine also preserves nitrogen availability for synthesis of nucleotides and non-essential amino acids. One of the most important functions of glutamine is its ability to be converted into α-KG, which helps to maintain the flow of the tricarboxylic acid cycle, generating ATPs.
Production
Glutamine is produced industrially using mutants of Brevibacterium flavum, which gives ca. 40 g/L in 2 days using glucose as a carbon source.
Glutamine is synthesized by the enzyme glutamine synthetase from glutamate and ammonia. The most relevant glutamine-producing tissue is the muscle mass, accounting for about 90% of all glutamine synthesized. Glutamine is also released, in small amounts, by the lungs and brain. Although the liver is capable of relevant glutamine synthesis, its role in glutamine metabolism is more regulatory than producing, since the liver takes up large amounts of glutamine derived from the gut.
Consumers
The most eager consumers of glutamine are the cells of intestines, the kidney cells for the acid-base balance, activated immune cells, and many cancer cells.
Uses
Nutrition
Glutamine is the most abundant naturally occurring, nonessential amino acid in the human body, and one of the few amino acids that can directly cross the blood–brain barrier. Humans obtain glutamine through catabolism of proteins in foods they eat. In states where tissue is being built or repaired, like growth of babies, or healing from wounds or severe illness, glutamine becomes conditionally essential.
Sickle cell disease
In 2017, the U.S. Food and Drug Administration (FDA) approved L-glutamine oral powder, marketed as Endari, to reduce severe complications of sickle cell disease in people aged five years and older with the disorder.The safety and efficacy of L-glutamine oral powder were studied in a randomized trial of subjects ages five to 58 years old with sickle cell disease who had two or more painful crises within the 12 months prior to enrollment in the trial. Subjects were assigned randomly to treatment with L-glutamine oral powder or placebo, and the effect of treatment was evaluated over 48 weeks. Subjects who were treated with L-glutamine oral powder experienced fewer hospital visits for pain treated with a parenterally administered narcotic or ketorolac (sickle cell crises), on average, compared to subjects who received a placebo (median 3 vs. median 4), fewer hospitalizations for sickle cell pain (median 2 vs. median 3), and fewer days in the hospital (median 6.5 days vs. median 11 days). Subjects who received L-glutamine oral powder also had fewer occurrences of acute chest syndrome (a life-threatening complication of sickle cell disease) compared with patients who received a placebo (8.6 percent vs. 23.1 percent).Common side effects of L-glutamine oral powder include constipation, nausea, headache, abdominal pain, cough, pain in the extremities, back pain and chest pain.L-glutamine oral powder received orphan drug designation. The FDA granted the approval of Endari to Emmaus Medical Inc.
Medical food
Glutamine is marketed as medical food and is prescribed when a medical professional believes a person in their care needs supplementary glutamine due to metabolic demands beyond what can be met by endogenous synthesis or diet.
Safety
Glutamine is safe in adults and in preterm infants. Although glutamine is metabolized to glutamate and ammonia, both of which have neurological effects, their concentrations are not increased much, and no adverse neurological effects were detected. The observed safe level for supplemental L-glutamine in normal healthy adults is 14 g/day.Adverse effects of glutamine have been prescribed for people receiving home parenteral nutrition and those with liver-function abnormalities.
Although glutamine has no effect on the proliferation of tumor cells, it is still possible that glutamine supplementation may be detrimental in some cancer types.Ceasing glutamine supplementation in people adapted to very high consumption may initiate a withdrawal effect, raising the risk of health problems such as infections or impaired integrity of the intestine.
Structure
Glutamine can exist in either of two enantiomeric forms, L-glutamine and D-glutamine. The L-form is found in nature. Glutamine contains an α-amino group which is in the protonated −NH3+ form under biological conditions and a carboxylic acid group which is in the deprotonated −COO− form, known as carboxylate, under physiological conditions.
Research
Glutamine mouthwash may be useful to prevent oral mucositis in people undergoing chemotherapy but intravenous glutamine does not appear useful to prevent mucositis in the GI tract.Glutamine supplementation was thought to have potential to reduce complications in people who are critically ill or who have had abdominal surgery but this was based on poor quality clinical trials. Supplementation does not appear to be useful in adults or children with Crohns disease or inflammatory bowel disease, but clinical studies as of 2016 were underpowered. Supplementation does not appear to have an effect in infants with significant problems of the stomach or intestines.Some athletes use L-glutamine as supplement. Studies support the positive effects of the chronic oral administration of the supplement on the injury and inflammation induced by intense aerobic and exhaustive exercise, but the effects on muscle recovery from weight training are unclear.
See also
Isoglutamine
References
External links
Glutamine spectra acquired through mass spectroscopy
"Glutamine". Drug Information Portal. U.S. National Library of Medicine. |
Bisacodyl | Bisacodyl (INN) is an organic compound that is used as a stimulant laxative drug. It works directly on the colon to produce a bowel movement. It is typically prescribed for relief of episodic and chronic constipation and for the management of neurogenic bowel dysfunction, as well as part of bowel preparation before medical examinations, such as for a colonoscopy.Bisacodyl is a derivative of triphenylmethane. It was first used as a laxative in 1953 because of its structural similarity to phenolphthalein.It is on the World Health Organizations List of Essential Medicines.
Available forms
Bisacodyl is marketed under the trade names Dulcolax/Durolax, Muxol, Fleet, Nourilax, Alophen, Correctol, and Carters Little Pills (formerly Carters Little Liver Pills), as well as being available generically. It is usually sold as 5 mg tablets, 10 mg suppositories, or 5 mg pediatric suppositories. It is also available as a 1.25 US fluid ounces (37 ml) pre-packaged enema containing a 10 mg delivered dose of liquid bisacodyl.
Administration
When bisacodyl is administered orally, it is usually taken at breakfast. Oral administration is known to produce no action for more than eight hours and then to work suddenly and relatively quickly. This is especially true if more than 10 mg is taken at one time. Normally, the dosage is 5 or 10 mg, but up to 30 mg can be taken for complete cleansing of the bowel before a procedure.
When administered rectally in suppository form, it is usually effective in 15 to 60 minutes. For optimal use, if used as a suppository, it is recommended that bisacodyl be given after breakfast to synchronize with the gastrocolic reflex. Two suppositories can be inserted at once if a very strong, purgative, enema-like result is needed. A few hours after the initial evacuation, there can be a secondary action which will continue as long as there is unexpelled bisacodyl present in the rectum.
As a commercially prepared micro-enema, it is usually effective in 5 to 20 minutes.
Mechanism of action
Bisacodyl works by stimulating enteric neurons to cause peristalsis, i.e., colonic contractions. It is also a contact laxative; it increases fluid and salt secretion. The action of bisacodyl on the small intestine is negligible; stimulant laxatives mainly promote evacuation of the colon.
See also
Diphenyl-2-pyridylmethane
Cyclofenil
References
External links
|Bisacodyl,00.html Bisacodyl at Drugdigest.org
Bisacodyl Consumer Drug Information
Dulcolax Laxative
Dulcoflex Tablet Uses in Hindi |
Umbralisib | Umbralisib, sold under the brand name Ukoniq, is a medication for the treatment of marginal zone lymphoma (MZL) and follicular lymphoma (FL). It is taken by mouth.Umbralisib is a kinase inhibitor including PI3K-delta and casein kinase CK1-epsilon.The most common side effects include increased creatinine, diarrhea-colitis, fatigue, nausea, neutropenia, transaminase elevation, musculoskeletal pain, anemia, thrombocytopenia, upper respiratory tract infection, vomiting, abdominal pain, decreased appetite, and rash.Umbralisib was granted accelerated approval for medical use in the United States in February 2021. However, due to concerns for increased long term side effects leading to inferior overall survival which led to increased FDA scrutiny in the form of an ODAC review, it has been withdrawn from the US market.
Medical uses
On April 15, 2022, TG Therapeutics announced the voluntary withdrawal of Ukoniq (umbralisib) from sale for its approved use in the treatment of marginal zone lymphoma and follicular lymphoma. Furthermore, the company withdrew the pending Biologics License Application (BLA) and supplemental New Drug Application (sNDA) for the treatment of chronic lymphocytic leukemia (CLL) and small lymphocytic leukemia (SLL) which utilized umbralisib in tandem with ublituximab, known as the "U2" regimen. The decision was based on the most recent overall survival (OS) data from the Phase 3 trial, Unity-CLL, that illustrated and increasing imbalance in OS.
Umbralisib was indicated for adults with relapsed or refractory marginal zone lymphoma (MZL) who have received at least one prior anti-CD20-based regimen; and adults with relapsed or refractory follicular lymphoma (FL) who have received at least three prior lines of systemic therapy.
Adverse effects
The prescribing information provides warnings and precautions for adverse reactions including infections, neutropenia, diarrhea and non-infectious colitis, hepatotoxicity, and severe cutaneous reactions.
History
It has undergone clinical studies for chronic lymphocytic leukemia (CLL). Three year data (including follicular lymphoma and DLBCL) was announced June 2016. It is in combination trials for various leukemias and lymphomas, such as mantle cell lymphoma (MCL) and other lymphomas.Umbralisib was granted breakthrough therapy designation by the U.S. Food and Drug Administration (FDA) for use in people with marginal zone lymphoma (MZL), a type of cancer with no specifically approved therapies.FDA approval was based on two single-arm cohorts of an open-label, multi-center, multi-cohort trial, UTX-TGR-205 (NCT02793583), in 69 participants with marginal zone lymphoma (MZL) who received at least one prior therapy, including an anti-CD20 containing regimen, and in 117 participants with follicular lymphoma (FL) after at least two prior systemic therapies. The application for umbralisib was granted priority review for the marginal zone lymphoma (MZL) indication and orphan drug designation for the treatment of MZL and follicular lymphoma (FL).
Society and culture
Legal status
In June 2022, due to safety concerns, the U.S. Food and Drug Administration (FDA) withdrew its approval for Ukoniq (umbralisib).Updated findings from the UNITY-CLL clinical trial show a possible increased risk of death in people receiving Ukoniq. As a result, the FDA determined the risks of treatment with Ukoniq outweigh its benefits. Based upon this determination, the drugs manufacturer, TG Therapeutics, announced it was voluntarily withdrawing Ukoniq from the market for the approved uses in MZL and FL.
References
External links
"Umbralisib". Drug Information Portal. U.S. National Library of Medicine.
"Umbralisib". NCI Drug Dictionary. National Cancer Institute. |
Nitisinone | Nitisinone, sold under the brand name Nityr and Orfadin among others, is a medication used to slow the effects of hereditary tyrosinemia type 1 (HT-1).
Uses
Nitisinone is used to treat hereditary tyrosinemia type 1 (HT-1) in patients from all ages, in combination with dietary restriction of tyrosine and phenylalanine.Since its first use for this indication in 1991, it has replaced liver transplantation as the first-line treatment for this ultra rare condition.
Adverse effects
The most common adverse reactions (>1%) for nitisinone are elevated tyrosine levels, thrombocytopenia, leukopenia, conjunctivitis, corneal opacity, keratitis, photophobia, eye pain, blepharitis, cataracts, granulocytopenia, epistaxis, pruritus, exfoliative dermatitis, dry skin, maculopapular rash and alopecia.has several negative side effects; these include but are not limited to: bloated abdomen, dark urine, abdominal pain, feeling of tiredness or weakness, headache, light-colored stools, loss of appetite, weight loss, vomiting, and yellow-colored eyes or skin.
Mechanism of action
The mechanism of action of nitisinone involves inhibition of 4-Hydroxyphenylpyruvate dioxygenase (HPPD). This is a treatment for patients with Tyrosinemia type 1 as it prevents the formation of 4-Maleylacetoacetic acid and fumarylacetoacetic acid, which have the potential to be converted to succinyl acetone, a toxin that damages the liver and kidneys. This causes the symptoms of Tyrosinemia type 1 experienced by untreated patients.Alkaptonuria is caused when an enzyme called homogentisic dioxygenase (HGD) is faulty, leading to a buildup of homogenisate. Alkaptonuria patients treated with nitisinone produce far less HGA than those not treated (95% less in the urine), because nitisinone inhibits HPPD, resulting in less homogenisate accumulation. Clinical trials are ongoing to test whether nitisinone can prevent ochronosis experienced by older alkaptonuria patients.
History
Nitisinone was discovered as part of a program to develop a class of herbicides called HPPD inhibitors. It is a member of the benzoylcyclohexane-1,3-dione family of herbicides, which are chemically derived from a natural phytotoxin, leptospermone, obtained from the Australian bottlebrush plant (Callistemon citrinus). HPPD is essential in plants and animals for catabolism, or breaking apart, of tyrosine. In plants, preventing this process leads to destruction of chlorophyll and the death of the plant. In toxicology studies of the herbicide, it was discovered that it had activity against HPPD in rats and humans.In Type I tyrosinemia, a different enzyme involved in the breakdown of tyrosine, fumarylacetoacetate hydrolase is mutated and doesnt work, leading to very harmful products building up in the body. Fumarylacetoacetate hydrolase acts on tyrosine after HPPD does, so scientists working on making herbicides in the class of HPPD inhibitors hypothesized that inhibiting HPPD and controlling tyrosine in the diet could treat this disease. A series of small clinical trials attempted with one of their compounds, nitisinone, were conducted and were successful, leading to nitisinone being brought to market as an orphan drug Swedish Orphan International, which was later acquired by Swedish Orphan Biovitrum (Sobi). In 201, Cycle Pharmaceuticals launched Nityr in the United States through Cycle Vita.
Research
Nitisinone is being studied as a treatment for alkaptonuria.
References
External links
"Nitisinone". Drug Information Portal. U.S. National Library of Medicine. |
Methylscopolamine bromide | Methylscopolamine or methscopolamine, usually provided as the bromide or nitrate salt, is an oral medication used along with other medications to treat peptic ulcers by reducing stomach acid secretion. Proton pump inhibitors and antihistamine medications have made this use obsolete. It can also be used for stomach or intestinal spasms, to reduce salivation, and to treat motion sickness. Methscopolamine is also commonly used as a drying agent, to dry up post-nasal drip, in cold, irritable bowel syndrome and allergy medicationsMethscopolamine, a methylated derivative of scopolamine, is a muscarinic antagonist structurally similar to the neurotransmitter acetylcholine. Its mechanism of action involves blocking the muscarinic acetylcholine receptors.
It was patented in 1902 and approved for medical use in 1947. Methscopolamine is an FDA-approved analog to hyoscine butylbromide.
Brand names
Brand names include Extendryl, AlleRx, Rescon, Pamine.
== References == |
Trilaciclib | Trilaciclib, sold under the brand name Cosela, is a medication used to reduce the frequency of chemotherapy-induced bone marrow suppression.The most common side effects include fatigue; low levels of calcium, potassium and phosphate; increased levels of an enzyme called aspartate aminotransferase; headache; and infection in the lungs (pneumonia).Trilaciclib may help protect bone marrow cells from damage caused by chemotherapy by inhibiting cyclin-dependent kinase 4/6, a type of enzyme. Trilaciclib is the first therapy in its class and was approved for medical use in the United States in February 2021.Chemotherapy drugs are designed to kill cancer cells but can damage normal tissues as well. The bone marrow is particularly susceptible to chemotherapy damage. The bone marrow makes red blood cells, white blood cells, and platelets (small fragments in the blood) that transport oxygen, fight infection, and stop bleeding. When damaged, the bone marrow produces fewer of these cells, leading to fatigue, increased risk of infection, and bleeding, among other problems. Trilaciclib may help protect the normal bone marrow cells from the harmful effects of chemotherapy.
Medical uses
Trilaciclib is indicated to reduce the frequency of chemotherapy-induced bone marrow suppression in adults receiving certain types of chemotherapy for extensive-stage (when the cancer has spread beyond the lungs) small cell lung cancer.
History
The effectiveness of trilaciclib was evaluated in three randomized, double-blind, placebo-controlled studies in participants with extensive-stage small cell lung cancer. Combined, these studies randomly assigned 245 participants to receive either an infusion of trilaciclib in their veins or a placebo before chemotherapy. The studies then compared the two groups for the proportion of participants with severe neutropenia (a very low count of white blood cells called neutrophils) and the duration of severe neutropenia in the first cycle of chemotherapy. In all three studies, participants who received trilaciclib had a lower chance of having severe neutropenia compared to participants who received a placebo. Among those who had severe neutropenia, participants who received trilaciclib, on average, had it for a shorter time than participants who received a placebo.The U.S. Food and Drug Administration (FDA) granted the application for trilaciclib priority review and breakthrough therapy designations. The FDA granted the approval of Cosela to G1 Therapeutics, Inc.
References
This article incorporates public domain material from the United States Department of Health and Human Services.
External links
"Trilaciclib". Drug Information Portal. U.S. National Library of Medicine.
Clinical trial number NCT03041311 for "Carboplatin, Etoposide, and Atezolizumab With or Without Trilaciclib (G1T28), a CDK 4/6 Inhibitor, in Extensive Stage Small Cell Lung Cancer (SCLC)" at ClinicalTrials.gov
Clinical trial number NCT02499770 for "Trilaciclib (G1T28), a CDK 4/6 Inhibitor, in Combination With Etoposide and Carboplatin in Extensive Stage Small Cell Lung Cancer (SCLC)" at ClinicalTrials.gov
Clinical trial number NCT02514447 for "Trilaciclib (G1T28), a CDK 4/6 Inhibitor, in Patients With Previously Treated Extensive Stage SCLC Receiving Topotecan Chemotherapy" at ClinicalTrials.gov |
Pancuronium bromide | Pancuronium (trademarked as Pavulon) is an aminosteroid muscle relaxant with various medical uses. It is used in euthanasia and is used in some states as the second of three drugs administered during lethal injections in the United States.
Mechanism of action
Pancuronium is a typical non-depolarizing curare-mimetic muscle relaxant. It competitively inhibits the nicotinic acetylcholine receptor at the neuromuscular junction by blocking the binding of acetylcholine. It has slight vagolytic activity, causing an increase in heart rate, but no ganglioplegic (i.e., blocking ganglions) activity. It is a very potent muscle relaxant drug, with an ED95 (i.e., the dose that causes 95% depression of muscle twitch response) of only 60 µg/kg body weight. Onset of action is relatively slow compared to other similar drugs, in part due to its low dose: an intubating dose takes 3–6 minutes for full effect. Clinical effects (muscle activity lower than 25% of physiological) last for about 100 minutes. The time needed for full (over 90% muscle activity) recovery after single administration is about 120–180 minutes in healthy adults.
The effects of pancuronium can be at least partially reversed by anticholinesterasics, such as neostigmine, pyridostigmine, and edrophonium.
Development
Workers at Organon were inspired by the structure of the aminosteroid alkaloid malouetine to develop a series of aminosteroid neuromuscular blockers based on an androstane nucleus, culminating in the development of pancuronium bromide.Pancuronium is designed to mimic the action of two molecules of acetylcholine with the quaternary nitrogen atoms spaced rigidly apart by the steroid rings at a distance of ten atoms (interonium distance).
Decamethonium and suxamethonium also have this same interonium distance.
Uses in medicine
Pancuronium is used with general anesthesia in surgery for muscle relaxation and as an aid to intubation or ventilation. It does not have sedative or analgesic effects.
Side-effects include moderately raised heart rate and thereby arterial pressure and cardiac output, excessive salivation, apnea and respiratory depression, rashes, flushing, and sweating. The muscular relaxation can be dangerous in the seriously ill and it can accumulate leading to extended weakness. Pancuronium is not preferable in long-term use in ICU-ventilated patients.
In Belgium and the Netherlands, pancuronium is recommended in the protocol for euthanasia. After administering sodium thiopental to induce coma, pancuronium is delivered in order to stop breathing.
Uses in execution and suicide
Procedure
Pancuronium is also used as one component of a lethal injection in administration of the death penalty in some parts of the United States.
Controversy
Like all non-depolarising muscle relaxants, pancuronium has no effect on level of consciousness. Therefore, if the anaesthetic used is insufficient, the individual may be awake but unable to cry out or move due to the effect of the pancuronium. There have been several civil lawsuits alleging similar failures of adequate anaesthesia during general surgical procedures. These have been largely due to improper or insufficient dosages of anaesthetic in concert with normal dosages of muscle relaxants such as pancuronium.
In 2007, Michael Munro, a Scottish neonatologist at Aberdeen Maternity Hospital, was cleared of malpractice by the GMC Fitness to Practice panel after giving 23 times the standard dose of pancuronium to two dying neonates. Terminally ill, both dying babies were suffering from agonal gasping and violent body spasms, which was highly distressing for the parents to witness. Munro then administered pancuronium to the babies after advising the parents that this would ease their suffering and could also hasten death. It is on record that neither of the childrens parents were unhappy with Dr Munros treatment of their babies.Amnesty International has objected to its use in lethal injections on the grounds that it "may mask the condemned prisoners suffering during the execution," thereby leading observers to conclude that lethal injection is painless, or less cruel than other forms of execution.
Export limitations
The United Kingdom bans the export of pancuronium bromide to the United States due to its use in lethal injections, but not to the Netherlands or Belgium.
Uses in crime
Pancuronium was used in Efren Saldivars killing spree. It was also used by the Skin Hunters to kill patients in the Polish city of Łódź. Pavulon was also used by Richard Angelo in 1987 to kill at least 10 patients under his care at the Good Samaritan Hospital in New York.
== References == |
Cefalexin | Cefalexin, also spelled cephalexin, is an antibiotic that can treat a number of bacterial infections. It kills gram-positive and some gram-negative bacteria by disrupting the growth of the bacterial cell wall. Cefalexin is a beta-lactam antibiotic within the class of first-generation cephalosporins. It works similarly to other agents within this class, including intravenous cefazolin, but can be taken by mouth.Cefalexin can treat certain bacterial infections, including those of the middle ear, bone and joint, skin, and urinary tract. It may also be used for certain types of pneumonia and strep throat and to prevent bacterial endocarditis. Cefalexin is not effective against infections caused by methicillin-resistant Staphylococcus aureus (MRSA), most Enterococcus, or Pseudomonas. Like other antibiotics, cefalexin cannot treat viral infections, such as the flu, common cold or acute bronchitis. Cefalexin can be used in those who have mild or moderate allergies to penicillin. However, it is not recommended in those with severe penicillin allergies.Common side effects include stomach upset and diarrhea. Allergic reactions or infections with Clostridium difficile, a cause of diarrhea, are also possible. Use during pregnancy or breast feeding does not appear to be harmful to the baby. It can be used in children and those over 65 years of age. Those with kidney problems may require a decrease in dose.Cefalexin was developed in 1967. It was first marketed in 1969 and 1970 under the names Keflex and Ceporex, among others. Generic drug versions are available under other trade names and are inexpensive. It is on the World Health Organizations List of Essential Medicines. In 2019, it was the 83rd most commonly prescribed medication in the United States, with more than 9 million prescriptions. In Canada, it was the fifth most common antibiotic used in 2013. In Australia, it is one of the top 15 most prescribed medications.
Medical uses
Cefalexin can treat a number of bacterial infections including otitis media, streptococcal pharyngitis, bone and joint infections, pneumonia, cellulitis, and urinary tract infections. It may be used to prevent bacterial endocarditis. It can also be used for the prevention of recurrent urinary-tract infections.Cefalexin does not treat methicillin-resistant Staphylococcus aureus infections.Cefalexin is a useful alternative to penicillins in patients with penicillin intolerance. For example, penicillin is the treatment of choice for respiratory tract infections caused by Streptococcus, but cefalexin may be used as an alternative in penicillin-intolerant patients. Caution must be exercised when administering cephalosporin antibiotics to penicillin-sensitive patients, because cross-sensitivity with beta-lactam antibiotics has been documented in up to 10% of patients with a documented penicillin allergy.
Pregnancy and breastfeeding
It is category A in Australia meaning that no evidence of harm has been found after being taken by many pregnant women. Use during breast feeding is generally safe.
Adverse effects
The most common adverse effects of cefalexin, like other oral cephalosporins, are gastrointestinal (stomach area) disturbances and hypersensitivity reactions. Gastrointestinal disturbances include nausea, vomiting, and diarrhea, the latter being the most common. Hypersensitivity reactions include skin rashes, urticaria, fever, and anaphylaxis. Pseudomembranous colitis and Clostridium difficile have been reported with use of cefalexin.Signs and symptoms of an allergic reaction include rash, itching, swelling, trouble breathing, or red, blistered, swollen, or peeling skin. Overall, cefalexin allergy occurs in less than 0.1% of patients, but it is seen in 1% to 10% of patients with a penicillin allergy.
Interactions
Like other β-lactam antibiotics, renal excretion of cefalexin is delayed by probenecid. Alcohol consumption reduces the rate at which it is absorbed. Cefalexin also interacts with metformin, an antidiabetic drug, and this can lead to higher concentrations of metformin in the body. Histamine H2 receptor antagonists like cimetidine and ranitidine may reduce the efficacy of cefalexin by delaying its absorption and altering its antimicrobial pharmacodynamics.
Pharmacology
Mechanism of action
Cefalexin is a beta-lactam antibiotic of the cephalosporin family. It is bactericidal and acts by inhibiting synthesis of the peptidoglycan layer of the bacterial cell wall. As cefalexin closely resembles d-alanyl-d-alanine, an amino acid ending on the peptidoglycan layer of the cell wall, it is able to irreversibly bind to the active site of PBP, which is essential for the synthesis of the cell wall. It is most active against gram-positive cocci, and has moderate activity against some gram-negative bacilli. However, some bacterial cells have the enzyme β-lactamase, which hydrolyzes the beta-lactam ring, rendering the drug inactive. This contributes to antibacterial resistance towards cefalexin.
Pharmacokinetics
Cefalexin is rapidly and almost completely absorbed from the gastrointestinal tract with oral administration. Absorption is slightly reduced when it is taken with food and the medication can be taken without regard for meals. Peak levels of cefalexin occur about 1 hour after administration. Maximal levels of cefalexin increase approximately linearly over a dose range of 250 to 1,000 mg.Like most other cephalosporins, cefalexin is not metabolized or otherwise inactivated in the body.The elimination half-life of cefalexin is approximately 30 to 60 minutes in people with normal renal function. Therapeutic levels of cefalexin with oral administration are maintained for 6 to 8 hours. For this reason, cefalexin is typically administered once every 6 to 12 hours depending on the indication. More than 90% of cefalexin is excreted unchanged in the urine within 8 hours.
Society and culture
It is on the World Health Organizations List of Essential Medicines. The World Health Organization classifies cefalexin as highly important for human medicine.
Names
Cefalexin is the International Nonproprietary Name (INN) and the Australian Approved Name (AAN), while cephalexin is the British Approved Name (BAN) and the United States Adopted Name (USAN). Brand names for cefalexin include Keflex, Acfex, Cephalex, Ceporex, L-Xahl, Medoxine, Ospexin, and Torlasporin.
Veterinary uses
Dogs
According to Plumbs Veterinary Medication Guides, cefalexin can be used in treating skin, respiratory tract, and urinary tract infections. The U.S. Food and Drug Administration (FDA) has approved it for use in humans and dogs but not for other species. Like other drugs approved for human use, cefalexin may be prescribed by veterinarians for animals in certain situations.
References
External links
"Cephalexin". Drug Information Portal. U.S. National Library of Medicine. |
Oxiconazole | Oxiconazole (trade names Oxistat in the US, Oxizole in Canada) is an antifungal medication typically administered in a cream or lotion to treat skin infections, such as athletes foot, jock itch and ringworm. It can also be prescribed to treat the skin rash known as tinea versicolor, caused by systemic yeast overgrowth (Candida spp.).
It was patented in 1975 and approved for medical use in 1983.
See also
Fluconazole
References
External links
MedlinePlus - Oxiconazole |
Doxycycline | Doxycycline is a broad-spectrum tetracycline class antibiotic used in the treatment of infections caused by bacteria and certain parasites. It is used to treat bacterial pneumonia, acne, chlamydia infections, Lyme disease, cholera, typhus, and syphilis. It is also used to prevent malaria in combination with quinine. Doxycycline may be taken by mouth or by injection into a vein.Common side effects include diarrhea, nausea, vomiting, abdominal pain, and an increased risk of sunburn. Use during pregnancy is not recommended. Like other agents of the tetracycline class, it either slows or kills bacteria by inhibiting protein production. It kills malaria by targeting a plastid organelle, the apicoplast.Doxycycline was patented in 1957 and came into commercial use in 1967. It is on the World Health Organizations List of Essential Medicines. Doxycycline is available as a generic medicine. In 2019, it was the 90th most commonly prescribed medication in the United States, with more than 8 million prescriptions.
Medical use
In addition to the general indications for all members of the tetracycline antibiotics group, doxycycline is frequently used to treat Lyme disease, chronic prostatitis, sinusitis, pelvic inflammatory disease, acne, rosacea, and rickettsial infections.In Canada, in 2004, doxycycline was considered a first-line treatment for chlamydia and non-gonococcal urethritis and with cefixime for uncomplicated gonorrhea.
Antibacterial
Moraxella catarrhalis, Brucella melitensis, Chlamydia pneumoniae, and Mycoplasma pneumoniae are generally susceptible to doxycycline, while some Haemophilus spp., Mycoplasma hominis, and Pseudomonas aeruginosa have developed resistance to varying degrees.It is used in the treatment and prophylaxis of anthrax and Leptospirosis. It is also effective against Yersinia pestis (the infectious agent of bubonic plague), and is prescribed for the treatment of Lyme disease, ehrlichiosis, and Rocky Mountain spotted fever.Doxycycline is indicated for treatment of:
Rocky Mountain spotted fever, typhus fever and the typhus group, Q fever, rickettsialpox, and tick fevers caused by Rickettsia
Respiratory tract infections caused by Mycoplasma pneumoniae
Lymphogranuloma venereum, trachoma, inclusion conjunctivitis, and uncomplicated urethral, endocervical, or rectal infections in adults caused by Chlamydia trachomatis
Psittacosis
Nongonococcal urethritis caused by Ureaplasma urealyticum
Relapsing fever due to Borrelia recurrentis
Chancroid caused by Haemophilus ducreyi
Plague due to Yersinia pestis
Tularemia
Cholera
Campylobacter fetus infections
Brucellosis caused by Brucella species (in conjunction with streptomycin)
Bartonellosis
Granuloma inguinale (Klebsiella species)
Lyme diseaseWhen bacteriologic testing indicates appropriate susceptibility to the drug, doxycycline may be used to treat these infections caused by Gram-negative bacteria:
Escherichia coli infections
Enterobacter aerogenes (formerly Aerobacter aerogenes) infections
Shigella species infections
Acinetobacter species (formerly Mima species and Herellea species) infections
Respiratory tract infections caused by Haemophilus influenzae
Respiratory tract and urinary tract infections caused by Klebsiella speciesSome Gram-positive bacteria have developed resistance to doxycycline. Up to 44% of Streptococcus pyogenes and up to 74% of S. faecalis specimens have developed resistance to the tetracycline group of antibiotics. Up to 57% of P. acnes strains developed resistance to doxycycline. When bacteriologic testing indicates appropriate susceptibility to the drug, doxycycline may be used to treat these infections caused by Gram-positive bacteria:
Upper respiratory infections caused by Streptococcus pneumoniae (formerly Diplococcus pneumoniae)
Skin and soft tissue infections caused by Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus infections
Anthrax caused by Bacillus anthracis infectionWhen penicillin is contraindicated, doxycycline can be used to treat:
Syphilis caused by Treponema pallidum
Yaws caused by Treponema pertenue
Listeriosis due to Listeria monocytogenes
Vincents infection caused by Fusobacterium fusiforme
Actinomycosis caused by Actinomyces israelii
Infections caused by Clostridium speciesDoxycycline may also be used as adjunctive therapy for severe acne.The first-line treatment for brucellosis is a combination of doxycycline and streptomycin and the second-line is a combination of doxycycline and rifampicin (rifampin).
Antimalarial
Doxycycline is active against the erythrocytic stages of Plasmodium falciparum but not against the gametocytes of P. falciparum. It is used to prevent malaria. It is not recommended alone for initial treatment of malaria, even when the parasite is doxycycline-sensitive, because the antimalarial effect of doxycycline is delayed.The World Health Organization (WHO) guidelines state that the combination of doxycycline with either artesunate or quinine may be used for the treatment of uncomplicated malaria due to P. falciparum or following intravenous treatment of severe malaria.
Antihelminthic
Doxycycline kills the symbiotic Wolbachia bacteria in the reproductive tracts of parasitic filarial nematodes, making the nematodes sterile, and thus reducing transmission of diseases such as onchocerciasis and elephantiasis. Field trials in 2005 showed an eight-week course of doxycycline almost eliminates the release of microfilariae.
Spectrum of susceptibility
Doxycycline has been used successfully to treat sexually transmitted, respiratory, and ophthalmic infections. Representative pathogenic genera include Chlamydia, Streptococcus, Ureaplasma, Mycoplasma, and others. The following represents MIC susceptibility data for a few medically significant microorganisms.
Chlamydia psittaci: 0.03 μg/mL
Mycoplasma pneumoniae: 0.016 μg/mL—2 μg/mL
Streptococcus pneumoniae: 0.06 μg/mL—32 μg/mL
Sclerotherapy
Doxycycline is also used for sclerotherapy in slow-flow vascular malformations, namely venous and lymphatic malformations, as well as post-operative lymphoceles.
Others
Subantimicrobial-dose doxycycline (SDD) is widely used as an adjunctive treatment to scaling and root planing for periodontitis. Significant differences were observed for all investigated clinical parameters of periodontitis in favor of the scaling and root planing + SDD group where SDD dosage regimens is 20 mg twice daily for three months in a meta-analysis published in 2011.
Contraindications
Pregnancy and lactation
Doxycycline is categorized by the FDA as a class D drug in pregnancy. Doxycycline crosses into breastmilk. Other tetracycline antibiotics are contraindicated in pregnancy and up to eight years of age, due to the potential for disrupting bone and tooth development. They include a class warning about staining of teeth and decreased development of dental enamel in children exposed to tetracyclines in utero, during breastfeeding or during young childhood. However, the FDA has acknowledged that the actual risk of dental staining of primary teeth is undetermined for doxycycline specifically. The best available evidence indicates that doxycycline has little or no effect on hypoplasia of dental enamel or on staining of teeth and the CDC recommends the use of doxycycline for treatment of Q fever and also for tick-borne rickettsial diseases in young children and others advocate for its use in malaria.
Other
Other contraindications are severe liver disease and concomitant use of isotretinoin or other retinoids, as both tetracyclines and retinoids can cause intracranial hypertension (increased pressure around the brain) in rare cases.
Adverse effects
Adverse effects are similar to those of other members of the tetracycline antibiotic group. Doxycycline can cause gastrointestinal upset. Oral doxycycline can cause pill esophagitis, particularly when it is swallowed without adequate fluid, or by persons with difficulty swallowing or impaired mobility. Doxycycline is less likely than other antibiotic drugs to cause Clostridium difficile colitis.
An erythematous rash in sun-exposed parts of the body has been reported to occur in 7.3–21.2% of persons taking doxycycline for malaria prophylaxis. One study examined the tolerability of various malaria prophylactic regimens and found doxycycline did not cause a significantly higher percentage of all skin events (photosensitivity not specified) when compared with other antimalarials. The rash resolves upon discontinuation of the drug.Unlike some other members of the tetracycline group, it may be used in those with renal impairment.Doxycycline use has been associated with increased risk of inflammatory bowel disease. In one large retrospective study, patients who were prescribed doxycycline for their acne had a 2.25-fold greater risk of developing Crohns disease.
Interactions
The combination of doxycycline with dairy, antacids, calcium supplements, iron products, laxatives containing magnesium, or bile acid sequestrants is not inherently dangerous, but any of these foods and supplements may decrease doxycyclines effectiveness.
Breakfast was observed to reduce doxycycline absorption significantly. Absorption of tetracycline occurs in the stomach and the upper small intestine. Absorption of tetracyclines has been reported to be impaired by milk products, aluminum hydroxide gels, sodium bicarbonate, calcium and magnesium salts, laxatives containing magnesium and iron preparations. The mechanisms responsible for decreased absorption appear to be chelation and an increase in gastric pH. ... In view of these results, it is advisable to instruct the patients to take doxycycline on an empty stomach.
Previously, doxycycline was believed to impair the effectiveness of many types of hormonal contraception due to CYP450 induction. Research has shown no significant loss of effectiveness in oral contraceptives while using most tetracycline antibiotics (including doxycycline), although many physicians still recommend the use of barrier contraception for people taking the drug to prevent unwanted pregnancy.
Pharmacology
Doxycycline, like other tetracycline antibiotics, is bacteriostatic. It works by preventing bacteria from reproducing through the inhibition of protein synthesis.Doxycycline is highly lipophilic so can easily enter cells, meaning the drug is easily absorbed after oral administration and has a large volume of distribution. It can also be re-absorbed in the renal tubules and gastrointestinal tract due to its high lipophillicity so has a long elimination half life, and does not accumulate in the kidneys of patients with kidney failure due to the compensatory excretion in faeces. Doxycycline–metal ion complexes are unstable at acid pH, therefore more doxycycline enters the duodenum for absorption than the earlier tetracycline compounds. In addition, food has less effect on absorption than on absorption of earlier drugs with doxycycline serum concentrations being reduced by about 20% by test meals compared with 50% for tetracycline.
Mechanism of action
Doxycycline is a broad-spectrum bacteriostatic antibiotic. It inhibits the synthesis of bacterial proteins by binding to the 30S ribosomal subunit, which is only found in bacteria. This prevents the binding of transfer RNA to messenger RNA at the ribosomal subunit meaning amino acids cannot be added to polypeptide chains and new proteins cannot be made. This stops bacterial growth giving the immune system time to kill and remove the bacteria.
Pharmacokinetics
The substance is almost completely absorbed from the upper part of the small intestine. It reaches highest concentrations in the blood plasma after one to two hours and has a high plasma protein binding rate of about 80–90%. Doxycycline penetrates into almost all tissues and body fluids. Very high concentrations are found in the gallbladder, liver, kidneys, lung, breast milk, bone and genitals; low ones in saliva, aqueous humour, cerebrospinal fluid (CSF), and especially in inflamed meninges. By comparison, the tetracycline antibiotic minocycline penetrates significantly better into the CSF and meninges.Doxycycline metabolism is negligible. It is actively excreted into the gut (in part via the gallbladder, in part directly from blood vessels), where some of it is inactivated by forming chelates. About 40% are eliminated via the kidneys, much less in people with end-stage kidney disease. The biological half-life is 18 to 22 hours (16±6 hours according to another source) in healthy people, slightly longer in those with end-stage kidney disease, and significantly longer in those with liver disease.
Chemistry
Expired tetracyclines or tetracyclines allowed to stand at a pH less than 2 are reported to be nephrotoxic due to the formation of a degradation product, anhydro-4-epitetracycline causing Fanconi syndrome. In the case of doxycycline, the absence of a hydroxyl group in C-6 prevents the formation of the nephrotoxic compound. Nevertheless, tetracyclines and doxycycline itself have to be taken with caution in patients with kidney injury, as they can worsen azotemia due to catabolic effects.
Chemical properties
Doxycycline, doxycycline monohydrate and doxycycline hyclate are yellow, crystalline powders with a bitter taste. The latter smells faintly of ethanol; a 1% aqueous solution has a pH of 2–3; and the specific rotation is
[
α
]
D
25
{\displaystyle [\alpha ]_{D}^{25}}
−110° cm³/dm·g in 0.01 N methanolic hydrochloric acid.
History
After penicillin revolutionized the treatment of bacterial infections in WWII, many chemical companies moved into the field of discovering antibiotics by bioprospecting. American Cyanamid was one of these, and in the late 1940s chemists there discovered chlortetracycline, the first member of the tetracycline class of antibiotics. Shortly thereafter, scientists at Pfizer discovered terramycin and it was brought to market. Both compounds, like penicillin, were natural products and it was commonly believed that nature had perfected them, and further chemical changes could only degrade their effectiveness. Scientists at Pfizer led by Lloyd Conover modified these compounds, which led to the invention of tetracycline itself, the first semi-synthetic antibiotic. Charlie Stephens group at Pfizer worked on further analogs and created one with greatly improved stability and pharmacological efficacy: doxycycline. It was clinically developed in the early 1960s and approved by the FDA in 1967.As its patent grew near to expiring in the early 1970s, the patent became the subject of lawsuit between Pfizer and International Rectifier that was not resolved until 1983; at the time it was the largest litigated patent case in US history. Instead of a cash payment for infringement, Pfizer took the veterinary and feed-additive businesses of International Rectifiers subsidiary, Rachelle Laboratories.In January 2013, the FDA reported shortages of some, but not all, forms of doxycycline "caused by increased demand and manufacturing issues". Companies involved included an unnamed major generics manufacturer that ceased production in February 2013, Teva (which ceased production in May 2013), Mylan, Actavis, and Hikma Pharmaceuticals. The shortage came at a particularly bad time, since there were also shortages of an alternative antibiotic, tetracycline, at the same time. The market price for doxycycline dramatically increased in the United States in 2013 and early 2014 (from $20 to over $1800 for a bottle of 500 tablets), before decreasing again.
Society and culture
Doxycycline is available worldwide under many brand names. Doxycycline is available as a generic medicine.
Research
Research areas have included:
Macular degeneration
Rheumatoid arthritis instead of minocycline (both of which have demonstrated modest efficacy for this disease)
Research reagent
Doxycycline and other members of the tetracycline class of antibiotics are often used as research reagents in in vitro and in vivo biomedical research experiments involving bacteria as well in experiments in eukaryotic cells and organisms with inducible protein expression systems using tetracycline-controlled transcriptional activation. The mechanism of action for the antibacterial effect of tetracyclines relies on disrupting protein translation in bacteria, thereby damaging the ability of microbes to grow and repair; however protein translation is also disrupted in eukaryotic mitochondria impairing metabolism and leading to effects that can confound experimental results. Doxycycline is also used in "tet-on" (gene expression activated by doxycycline) and "tet-off" (gene expression inactivated by doxycycline) tetracycline-controlled transcriptional activation to regulate transgene expression in organisms and cell cultures. Doxycycline is more stable than tetracycline for this purpose. At subantimicrobial doses, doxycycline is an inhibitor of matrix metalloproteases, and has been used in various experimental systems for this purpose, such as for recalcitrant recurrent corneal erosions.
COVID-19
After a large-scale trial showed no benefit of using doxycycline in treating COVID‑19, the UKs National Institute for Health and Care Excellence (NICE) updated its guidance to not recommend the medication for the treatment of COVID‑19.
References
External links
"Doxycycline". Drug Information Portal. U.S. National Library of Medicine. |
Montelukast | Montelukast, sold under the brand name Singulair among others, is a medication used in the maintenance treatment of asthma. It is generally less preferred for this use than inhaled corticosteroids. It is not useful for acute asthma attacks. Other uses include allergic rhinitis and hives of long duration. For allergic rhinitis it is a second-line treatment.Common side effects include abdominal pain, cough, and headache. Severe side effects may include allergic reactions, such as anaphylaxis and eosinophilia. Use in pregnancy appears to be safe. Montelukast is in the leukotriene receptor antagonist family of medications. It works by blocking the action of leukotriene D4 in the lungs resulting in decreased inflammation and relaxation of smooth muscle.Montelukast was approved for medical use in the United States in 1998. It is available as a generic medication. In 2020, it was the fourteenth most commonly prescribed medication in the United States, with more than 31 million prescriptions.
Medical uses
Montelukast is used for a number of conditions including asthma, exercise induced bronchospasm, allergic rhinitis, and urticaria. It is mainly used as a complementary therapy in adults in addition to inhaled corticosteroids, if inhaled steroids alone do not bring the desired effect. It is also used to prevent allergic reactions and asthma flare-ups during the administration of intravenous immunoglobulin. It may also be used as an adjunct therapy in symptomatic treatment of mastocytosis. It is taken by mouth, as a tablet, chewable tablet, or as granules.
Adverse effects
Common side effects include diarrhea, nausea, vomiting, mild rashes, asymptomatic elevations in liver enzymes, and fever. Uncommon side effects include fatigue and malaise, behavioral changes, paresthesias and seizures, muscle cramps, and nose bleeds. Rare (may affect up to 1 in 10,000 people taking montelukast) but serious side effects include behavioral changes (including suicidal thoughts), angioedema, erythema multiforme, and liver problems.In 2019 and 2020, concerns for neuropsychiatric reactions were added to the label in the United Kingdom and United States where the most frequently suspected were nightmares, depression, insomnia (may affect between 1 in 100 to 1 in 1,000 people taking montelukast); aggression, anxiety and abnormal behaviour or changes in behaviour (may affect between 1 in 1,000 and 1 in 10,000 people taking montelukast).
FDA investigation
In June 2009, the U.S. Food and Drug Administration (FDA) concluded a review into the possibility of neuropsychiatric side effects with leukotriene modulator drugs. Although clinical trials only revealed an increased risk of insomnia, post-marketing surveillance showed that the drugs are associated with a possible increase in suicidal behavior and other side effects such as agitation, aggression, anxiousness, dream abnormalities and hallucinations, depression, irritability, restlessness, and tremor.In September 2019, the Pediatric Advisory Committee and the Drug Safety and Risk Management Advisory Committee met to discuss a pediatric-focused safety review of neuropsychiatric events with montelukast.In March 2020, the FDA required a boxed warning for montelukast to strengthen an existing warning about the risk of neuropsychiatric events associated with the drug in the wake of an increase in case reporting of neuropsychiatric events around the time of the initial communications about the concern from FDA in 2008. The boxed warning advises health care providers to avoid prescribing montelukast for people with mild symptoms, particularly those with allergic rhinitis because there are many other effective, less-concerned allergy medicines that are also indicated for the mild cases.In the FDAs self-conducted data analysis in comparison to their received case reports which were dependent on peoples self-claims, the propensity of developing neuropsychiatric disorders after montelukast use does not outpace that of inhaled corticosteroids; and there were no statistically significant risks of new-onset neuropsychiatric disorders among males, females, patients 12 years and older, patients with a psychiatric history, or after the 2008 FDA communication and prescribing information changes that first publicized the concern. In addition, FDAs self-conducted data analysis also summarized their own findings, saying "exposure to montelukast was significantly associated with a decreased risk of treated outpatient depressive disorder and the decreased risks were seen among patients with a history of a psychiatric disorder, in patients 12 to 17 years as well as 18 years and older, and in both females and males." "Treated outpatient depressive disorder" refers to patients actions of making an appointment with psychiatrists to contend with their depressions.
Drug interactions
Montelukast has very few drug-drug interactions. This is due to the lack of off-target affinity towards other targets in the body where it might exert an effect. However, it is important to note that montelukast is an inhibitor of the drug metabolizing enzyme CYP2C8. Therefore, it is theoretically possible that the combination of montelukast with a CYP2C8 substrate (e.g. amodiaquine, an anti-malarial drug) could increase the plasma concentrations of the substrate.
Pharmacology
Montelukast is in the leukotriene receptor antagonist family of medications. It works by blocking the action of leukotriene D4 in the lungs resulting in decreased inflammation and relaxation of smooth muscle.Montelukast functions as a leukotriene receptor antagonist (cysteinyl leukotriene receptors) and consequently opposes the function of these inflammatory mediators; leukotrienes are produced by the immune system and serve to promote bronchoconstriction, inflammation, microvascular permeability, and mucus secretion in asthma and COPD. Leukotriene receptor antagonists are sometimes colloquially referred to as leukasts.
Two genes of interest are ALOX5 and LTC4S, which catalyze two major steps in the biosynthetic pathway of leukotrienes.Montelukast may affect nerve remyelination in combination with Pexidartinib and this may cause clinical benefits or side effects.
Patents
Singulair was covered by U.S. Patent No. 5,565,473 which expired on 3 August 2012. The same day, the FDA approved several generic versions of montelukast.The United States Patent and Trademark Office launched a reexamination of the patent covering Singulair on 28 May 2009. The decision was driven by the discovery of references that were not included in the original patent application process. The references were submitted through Article One Partners, an online research community focused on finding literature relating to existing patents. The references included a scientific article produced by a Merck employee on the active ingredient in Singulair. A previously filed patent had been submitted in the same technology area. Seven months later the U.S. Patent and Trademark Office determined that the patent in question was valid based on the initial reexamination and new information provided, submitting their decision on 17 December 2009.
Use with loratadine
Schering-Plough and Merck sought permission to market a combined tablet with loratadine and montelukast. However, the FDA has found no benefit from a combined pill for seasonal allergies over taking the two drugs in combination, and on 25 April 2008, issued a not-approvable letter for the combination.
Names
The Mont in montelukast stands for Montreal, the place where Merck (MSD) developed the drug.Montelukast is sold under a variety of brand names including Monalast (Ziska Pharmaceuticals Ltd) Montenaaf (NAAFCO Pharma) Montelon-10 (Apex), Montene (Square), Montair-10, Montelo-10, Monteflo, and Tukast L in India, Reversair (ACI Bangladesh), Monas, Miralust, Montiva, Provair, Montril, Lumona, Lumenta, Arokast and Trilock in Bangladesh, Ventair in Nepal, Montika in Pakistan, Montelair in Brazil, Zykast in the Philippines though combined with levocetirizine, Desmont, Levmont, Aircomb and Notta in Turkey, Topraz in South Africa and AirOn in Venezuela.
References
External links
"Montelukast". Drug Information Portal. U.S. National Library of Medicine.
"Montelukast sodium". Drug Information Portal. U.S. National Library of Medicine. |
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