Santos 2022: targeted naltrexone for binge drinking in sexual and gender minority men

What they tested

Sexual and gender minority men who binge drink and have mild to moderate alcohol use disorder were randomly assigned 1:1 to targeted (as-needed) oral naltrexone 50 mg or a placebo, a dummy pill, with weekly counselling, for 12 weeks. Neither the men nor the staff knew who got which.

The main outcomes were drinks in the past 30 days, any binge drinking in the past week, binge-drinking days in the past week and drinking days in the past week. Two lab tests checked alcohol use: ethyl glucuronide in urine and phosphatidylethanol (PEth) in dried blood spots.

What they found

Ninety-three percent finished the trial. In the analysis of everyone as randomized, naltrexone led to fewer binge-drinking days (IRR 0.74; number needed to treat 2), fewer weeks with any binge drinking (IRR 0.83), fewer drinks per month (IRR 0.69) and lower craving scores. An incidence rate ratio below 1 means less of the behavior on naltrexone.

Among men who took the medicine at least 2.5 days a week on average, the median in the study, naltrexone also reduced any binge drinking (IRR 0.84), binge-drinking days (IRR 0.67) and PEth levels, a blood marker of drinking.

Six months after treatment ended, the naltrexone group still had fewer drinks per month (IRR 0.69), fewer binge-drinking days (IRR 0.67) and less binge drinking in the past week (IRR 0.79).

The abstract reports no significant effect on the number of drinking days, one of the four main outcomes.

Limits

• It included only sexual and gender minority men with mild to moderate alcohol use disorder, so it can't speak for women or for people with severe alcohol use disorder.
• Most drinking outcomes were self-reported. The blood marker PEth showed a drop only among men who took the medicine regularly.
• Everyone also got weekly counselling, so the results apply to naltrexone plus counselling.

What it means if you're considering naltrexone

This trial adds placebo-controlled evidence that naltrexone taken as needed, rather than every day, can cut binge drinking in people with mild to moderate alcohol use disorder. The typical man took it about 2.5 days a week, and the benefit on binge drinking lasted after the pills stopped.