Naltrexone hydrochloride

Abstract

Opioid dependence is a major problem in society. There are over a half million persons addicted to heroin, and over two million occasional or 'controlled' heroin users in the United States. As many as 75% of the heroin-dependent individuals may experience an affective disorder sometime in their lifetime. Opioid dependence has been described as a chronic, relapsing disorder with an unfavorable prognosis. Naltrexone seems to be a dependence-free narcotic antagonist with minimal side-effects (15). Because it does not produce dependence, it is not controlled by the Drug Enforcement Administration (DEA). Naltrexone is a competitive antagonist at the mu, kappa and delta receptors. Naltrexone is an almost pure antagonist. Drug is well absorbed orally, with peak levels achieved in 1 h (26). It is almost completely absorbed (27), but a considerable amount is metabolized by the liver on first pass. O'Brien (91) summarized what he considered some of the most important points about naltrexone's use following the symposium at the National Academy of Sciences. Despite the fact that placebo-controlled studies have not been able to demonstrate its effectiveness, it is still a useful drug when the population is properly selected and appropriate support is given. It is also relatively non-toxic. Three groups singled out in which he thought naltrexone would be of particular value were in work-release programs, in highly motivated professionals and businessmen, and in young addicts who had not yet become 'strung out'. Naltrexone has the capacity to cause dose-related hepatocellular injury. Prior to making a decision to initiate treatment, the physician should establish whether the patient has subclinical liver injury or disease. Among opioid-free individuals, naltrexone administration at the recommended dose has not been associated with a predictable profile of serious adverse or untoward events. However, as mentioned above, among individuals using opioids, naltrexone may cause serious reactions.