McPheeters 2023 (JAMA): which medicines work for alcohol use disorder

What they tested

The reviewers searched six databases for randomized trials of medicines for alcohol use disorder lasting at least 12 weeks, from November 2012 to September 2022, and kept watching for new studies until August 2023. For side effects, they also included prospective cohort studies. Two reviewers assessed each study and graded the strength of evidence.

They pooled results in a meta-analysis, which combines the results of many trials, and calculated numbers needed to treat: how many people need to take a medicine for one more person to benefit. The main outcome was alcohol consumption.

What they found

To prevent one person returning to any drinking, 11 needed to take acamprosate (95% CI 1-32) and 18 needed to take oral naltrexone 50 mg (95% CI 4-32).

Compared with placebo, oral naltrexone 50 mg was linked to lower rates of return to heavy drinking, with a number needed to treat of 11 (95% CI 5-41).

Injectable naltrexone was linked to fewer drinking days over the 30-day treatment period (weighted mean difference -4.99 days).

Stomach and gut side effects were more common. Naltrexone raised the risk of nausea (risk ratio 1.73) and vomiting (risk ratio 1.53) compared with placebo, and acamprosate raised the risk of diarrhea (risk ratio 1.58).

Limits

• The confidence intervals around the numbers needed to treat were wide, for example 4 to 32 for oral naltrexone and any drinking.
• The results apply to medicines given along with psychosocial interventions.
• Only trials of 12 weeks or longer counted for benefit.

What it means if you're considering naltrexone

This large pooling of the trial evidence supports oral naltrexone 50 mg as a first-line option for alcohol use disorder. Fewer people needed to take it to prevent one return to heavy drinking (11) than to prevent one return to any drinking (18), in line with the site's guides, which say it cuts heavy drinking more reliably than it stops drinking altogether. Nausea and vomiting were the side effects that stood out.