Effect of naltrexone on human alcohol consumption.

Opioid neurotransmitter systems have been shown to mediate certain aspects of alcohol consumption in animals and in humans. Use of opioid antagonists appears to decrease alcohol consumption in animals. Controlled clinical trials have indicated that alcohol-dependent subjects who are treated with a combination of naltrexone, an opioid antagonist, and traditional psychological and social therapies consume less alcohol and have lower relapse rates. The neurobiological mechanisms by which naltrexone acts to reduce alcohol consumption are still being investigated; however, there is evidence that naltrexone modifies the reinforcing effects of alcohol. Some researchers suggest that the reinforcing stimulant effects of alcohol and other psychoactive substances play a primary role in initiating and maintaining substance abuse and dependence. These effects may be mediated through the action of endogenous opioids. This article discusses the possible mechanisms of action of naltrexone and reviews human and animal studies that support the use of naltrexone in the treatment of alcohol dependence.