Naltrexone and alcohol dependence. Role of subject compliance

Two previous double-blind, placebo-controlled studies demonstrated that naltrexone (50 mg/d) reduces alcohol drinking in alcohol-dependent subjects. In both studies, treatment compliance was excellent. However, a robust treatment effect size for naltrexone relative to placebo has been shown for compliant subjects but not for subjects who missed research visits. The goal of this study was to determine the effectiveness of naltrexone in subjects who received psychosocial treatment in a more naturalistic setting with respect to the role of treatment attendance and medication compliance.

Ninety-seven alcohol-dependent subjects were randomly assigned to receive either naltrexone (n = 48) or matching placebo (n = 49) for 12 weeks. All subjects received individual counseling (twice per week for the first month followed by once per week).

Overall, naltrexone showed only modest effects in reducing alcohol drinking for the 12 weeks of treatment. However, naltrexone treatment efficacy improved across a variety of outcome measures for subjects who completed treatment and were highly compliant with taking medication.

Naltrexone is clinically effective relative to placebo in individuals who comply with the treatment protocol and take medication. The modest treatment effects in the entire sample suggest that the clinical efficacy of naltrexone could be improved by enhancing treatment compliance.