Rösner 2010 (Cochrane): acamprosate for alcohol dependence

What they tested

A Cochrane review, which pools the results of many trials using strict rules, gathered every double-blind randomized trial comparing acamprosate with a placebo (dummy pill) or another medicine on drinking outcomes. The searches ran through January 2009, and the authors asked drug makers and researchers about unpublished trials.

Two authors pulled out the data independently. The team also used individual patient data, the raw records from trials, to check the main results.

What they found

Compared with placebo, acamprosate significantly reduced the risk of any drinking (RR 0.86, 95% CI 0.81 to 0.91). The number needed to treat was 9.09, meaning that many people need to take it for one more person to avoid drinking. It also increased cumulative abstinence time (MD 10.94).

Two secondary outcomes, heavy drinking and gamma-glutamyltransferase (GGT, a liver blood test linked to drinking), did not reach statistical significance.

Diarrhea was the only side effect reported more often on acamprosate than placebo (RD 0.11).

Industry-funded trials (RR 0.88) and non-profit trials (RR 0.88) showed similar effects, and a statistical test didn't find signs of publication bias, the tendency for positive trials to get published more often (p = 0.861).

Limits

• The abstract doesn't break down results by how long trials lasted or how severe people's drinking was.
• The searches ended in January 2009, so later trials aren't included.
• The authors themselves described the size of the effects as rather moderate.

What it means if you're considering naltrexone

For someone choosing between medicines, this review shows acamprosate helps people avoid drinking at all after detox, but it didn't clearly reduce heavy drinking. The companion Cochrane review found the reverse pattern for naltrexone: a clear effect on heavy drinking and a borderline one on any drinking.

That fits the site's comparison guide, which describes acamprosate as leaning slightly toward abstinence and naltrexone slightly toward reducing heavy drinking. Both reviews pooled trials of each drug against placebo, not against each other.