Kranzler 2003: daily vs targeted naltrexone for problem drinkers

What they tested

Early problem drinkers were randomly given naltrexone 50 mg or a placebo, taken either every day or only in situations they saw as high risk for heavy drinking. That made four groups of similar size.

Everyone kept a structured diary each night of how much they drank and when they took their medicine. Over the 8 weeks, the number of tablets available to the targeted groups was reduced.

What they found

People in the targeted groups were less likely to drink at all, whether their pill was naltrexone or placebo.

Heavy drinking was less likely both for people on naltrexone and for people in the targeted groups, including those on placebo. These effects shrank as the targeted groups were given fewer tablets.

Daily naltrexone reduced the risk of heavy drinking, though the authors called the effect modest. They said the findings need to be repeated.

Limits

• It was short (8 weeks) and fairly small, and the people in it were early problem drinkers rather than people with severe dependence.
• The targeted groups had their tablet supply cut over time, which makes it harder to judge targeted use on its own.
• The targeted schedule was tied to situations people judged risky, which is not the same as Sinclair's rule of taking it before every drinking session.

What it means if you're considering naltrexone

This trial supports naltrexone as one option for early problem drinkers, with modest benefits. It also hints that planning ahead for risky situations, with a pill as a cue, may help by itself, so part of what people credit to as-needed naltrexone may come from the planning.