Naltrexone (brand names Trexan^R, Revia^R [U.S.], Nalorex^R [France, U.K.]) is a synthetic antagonist of opiate (morphine-like) drugs, which blocks their actions without itself having any opiate effects. Naltrexone differs from most other pure opiate antagonists in having a relatively long duration of action (at least 24 hours) and being effective when taken by mouth. These characteristics have led to its clinical use as a long-term or maintenance treatment for OPIATE and OPIOID dependence after detoxification. Naltrexone is also being studied experimentally as a possible treatment for cigarette smoking and eating disorders, and was approved in 1995 for treatment of alcoholism.

The use of opiate ANTAGONISTS as treatment for opiate dependence was first proposed by William Martin and Abraham Wikler and their colleagues at the U.S. Addiction Research Center in the early 1960s. They hypothesized...