Naltrexone Treatment for Alcohol Dependency

To the Editor: The study by Dr Garbutt and colleagues¹ demonstrates that the use of injectable naltrexone reduces the number of heavy drinking days in alcohol-dependent individuals. An important limitation in these results is that despite the long duration of the trial, the number of heavy drinking days per month did not progressively decrease over time, suggesting that longer treatment would be of no additional benefit. This is not surprising since craving, which is the strongest predictor of subsequent drinking and relapse,² has never been reported to be completely eliminated by naltrexone. Reduction of heavy drinking days has been previously established in randomized trials with the oral administration of the craving-reducing agents naltrexone,³ topiramate,⁴ and low-dose baclofen,⁵ and in an open-label trial of acamprosate.⁶