Clonidine (Catapres), an α2-agonist antihypertensive that alleviates opioid withdrawal by reducing sympathetic responses, can in excessive doses cause sedation, impaired consciousness, and seizures. Clonidine frequently is abused by opiate addicts, many of whom are apparently well aware of its potential for abuse. Abusers may take clonidine to decrease opioid withdrawal, tolerate periods of opioid scarcity, or for its psychotropic or euphoric effects. Clonidine has been abused alone or in combination with drugs such as diazepam.[87,88]
Cimetidine (Tagamet) may effect microsomal enzymes and reduce the ability of the liver to metabolize drugs, increasing their bioavailability. Substance abusers sometimes take cimetidine before methadone or cocaine to strengthen or prolong their response. Referred to as the "poor man's methadone," loperamide (Imodium) acts on opioid receptors in the intestine, but crosses the blood–brain barrier poorly and is therefore believed to have little abuse potential; however the drug has been used illicitly to alleviate opioid withdrawal symptoms in dosages of 70 to 100 mg/day (the indicated daily dose is 16 mg/day).
South Med J. 2015;108(3):151-157. © 2015 Lippincott Williams & Wilkins