(intravenous), IM (intramuscular), and SC (subcutaneous) injection. An extended release (ER) modified-release dosage form is commonly used, which modifies the pharmacokinetics of the drug. Oral dosage forms Oxymorphone comes in a variety of doses. Special populations Patients already suffering from debilitation are at a much higher risk of respiratory depression. Nonopioid analgesics should be considered in this population. Elderly patients are much more sensitive to adverse effects, such as falls, cognitive impairment and constipation, and should be monitored for such. Decreased renal function associated with aging leads to decreased clearance of the drug, resulting in narrow therapeutic windows and increasing the danger of overdose. If oxymorphone is absolutely indicated, smaller initial doses should be started for this population. There is a risk of neonatal withdrawal symptom in the newborn if pregnant women take oxymorphone for a prolonged period. Oxymorphone crosses the placenta and holds risk of birth defects, poor fetal growth, stillbirth, and preterm delivery. The children of mothers who are physically dependent on oxymorphone have a higher risk of similar dependence. Due to these severe risks, oxymorphone is highly discouraged among this population. The amount of transfer of oxymorphone into the breast milk is not known and women are cautioned to weigh the risks and benefits before breastfeeding while on this medication. Side effects The principal adverse effects of oxymorphone are similar to other opioids with constipation, nausea, vomiting, dizziness, dry mouth and drowsiness being the most common adverse effects. This drug is highly addictive as with other opioids and can lead to chemical dependence and withdrawal. Overdose In common with other opioids, oxymorphone overdosage is characterized by respiratory depression, sleepiness progressing to stupor or coma, skeletal muscle weakness, cold and clammy skin, and sometimes slow heart rate and low blood pressure. In a severe case of overdose, apnea, circulatory collapse, cardiac arrest and death can occur. Pharmacology Pharmacodynamics Oxymorphone elicits its effects by binding to and activating the μ-opioid receptor (MOR) and, to a much lesser extent, the δ-opioid receptor (DOR) and κ-opioid receptor (KOR). Its activity at the DOR may augment its action at the MOR. Oxymorphone is 10 times more potent than morphine. The calculation of relative potency indicated that 1 mg of oxymorphone hydrochloride equaled 9.85 mg of morphine sulfate, or 1.02 mg of oxymorphone hydrochloride was equivalent to 10 mg of morphine sulfate. Pharmacokinetics Chemistry Oxymorphone is commercially produced from thebaine, which is a