Efficacy and tolerability of naltrexone in the treatment of alcohol dependence: oral versus injectable delivery.

Oral naltrexone, an opioid antagonist, reduces relapse and heavy drinking in alcohol-dependent patients. However, oral delivery is associated with poor compliance and adverse events. To enhance treatment outcome and reduce side effects, injectable extended-release naltrexone formulations have been developed. Currently, there are no studies available directly comparing oral and injectable formulations of naltrexone in alcohol-dependent patients. This paper reviews the efficacy and adverse events of oral versus injectable extended-release naltrexone. Therefore, data were extracted from two recently published reviews about oral naltrexone in the treatment of alcohol dependence. Pooled outcomes were compared with reported outcomes of recent studies on injectable extended-release naltrexone. Injectable naltrexone seems to be effective in the management of alcohol dependence. Although inconclusive, the available results indicate that the expected advantages of injectable naltrexone over oral naltrexone still have to be proven. Randomized studies with direct comparisons of oral and injectable naltrexone are urgently needed.