 This is a double-blind, placebo-controlled trial of 120 binge-drinking MSM to 12 weeks of naltrexone 50mg, to be taken in anticipation of heavy drinking. Ethnically and racially diverse participants will be recruited using Respondent Driven Sampling as well as active field recruitment. MSM will be seen weekly for alcohol-metabolite urine testing, study drug dispensing, and brief counseling for alcohol use. Safety assessments and behavioral surveys will be completed monthly. 