50 to 70% of women receiving minocycline. As a result of the frequency of this bothersome side effect, minocycline is rarely used in female patients. Symptoms of an allergic reaction include rash, itching, swelling, severe dizziness, and trouble breathing. Minocycline has also been reported to very rarely cause idiopathic intracranial hypertension (pseudotumor cerebri), a side effect also more common in female patients, potentially leading to permanent vision damage if not recognized early and treated. Contrary to most other tetracycline antibiotics (doxycycline excluded), minocycline may be used in those with kidney disease, but may aggravate systemic lupus erythematosus. It may also trigger or unmask autoimmune hepatitis. Minocycline can cause the rare condition of secondary intracranial hypertension, which has initial symptoms of headache, visual disturbances, dizziness, vomiting, and confusion. Brain swelling and rheumatoid arthritis are rare side effects of minocycline in some people. Minocycline, like most tetracyclines, becomes dangerous past its expiration date. While most prescription drugs lose potency after their expiration dates, tetracyclines are known to become toxic over time. Expired tetracyclines can cause serious damage to the kidney due to the formation of a degradation product, anhydro-4-epitetracycline. Minocycline's absorption is impaired if taken at the same time of day as calcium or iron supplements. Unlike some of the other tetracycline group antibiotics, it can be taken with calcium-rich foods such as milk, although this does reduce the absorption slightly. Minocycline, like other tetracyclines, is associated with esophageal irritation and ulceration if insufficient fluids are taken with the drug before sleep. A 2007 study suggested that minocycline harms amyotrophic lateral sclerosis patients. Patients on minocycline declined more rapidly than those on placebo. The mechanism of this side effect is unknown, although a hypothesis is that the drug exacerbated an autoimmune component of the primary disease. The effect does not seem to be dose-dependent because the patients on high doses did not do worse than those on the low doses. The use of minocycline in acne vulgaris has been associated with skin and gut dysbiosis (see antibiotic misuse). Interactions The combination of minocycline with dairy, antacids, calcium and magnesium supplements, iron products, laxatives containing magnesium, or bile acid sequestrants may decrease minocycline's effectiveness by forming chelates. Combining it with isotretinoin, acitretin or other retinoids can increase the risk for intracranial hypertension. Minocycline significantly reduces concentrations of the anti-HIV drug atazanavir in the body. Pharmacology Mechanism of action Pharmacokinetics Minocycline is quickly and