Hernandez-Avila 2006: targeted vs daily naltrexone and drinks per day

What they tested

People were randomly given naltrexone 50 mg or a placebo (a dummy pill), either every day or on a targeted schedule, meaning they took it when they expected to drink. Neither they nor the researchers knew who had the real drug. Everyone also had brief coping skills therapy.

The same team had already reported that naltrexone lowered the chance of heavy drinking on a given day and that targeted use lowered the chance of any drinking. Here they used a different statistical model to look at the number of standard drinks per day, and checked whether results differed between men and women.

What they found

Targeted naltrexone led to a bigger drop in drinks per day than daily placebo. Targeted placebo also beat daily placebo, though by less. The benefit of targeted treatment was similar in men and women, and it was larger than the effect of daily naltrexone.

Compared with daily placebo, daily naltrexone reduced drinks per day only in men, and even then the difference was a trend that didn't reach statistical significance. Heavy drinking women got no benefit from daily naltrexone.

The authors concluded that targeted naltrexone was somewhat better than the other options, and that targeted treatment, daily naltrexone and the role of gender all need more study.

Limits

• It is a second look at an existing trial, using a new statistical method, so it doesn't add new patients or new evidence.
• The trial was short (8 weeks) and included problem drinkers rather than people being treated for severe alcohol dependence.
• Because the targeted placebo group also improved, part of the benefit of targeted dosing may come from planning ahead for risky situations rather than from the drug.

What it means if you're considering naltrexone

This is one of the few controlled tests of taking naltrexone only when drinking is likely, the idea behind as-needed approaches such as the Sinclair Method. It suggests targeted use can reduce how much people drink, but the improvement seen with a targeted placebo means the drug's own share of the effect is smaller than the raw results suggest.

The finding that daily naltrexone didn't help women in this trial is a single result in a small group, and it was flagged by the authors as needing further study.