Wadden 2011 (COR-BMOD): naltrexone-bupropion with intensive behavior therapy

What they tested

793 adults were randomly assigned, in a 1 to 3 ratio, to placebo (202 people) or to sustained-release naltrexone 32 mg a day plus sustained-release bupropion 360 mg a day (591 people). Everyone was prescribed a lower-calorie diet and 28 group sessions of behavior modification.

The two main measures were the percentage of weight lost and the share of people who lost at least 5% of their weight by week 56. The main analysis included people with at least one weight check while on the study drug (193 on placebo and 482 on the combination), with missing weights filled in by each person's last weight on the drug.

What they found

In the main analysis, people on naltrexone-bupropion lost 9.3% of their body weight on average, against 5.1% on placebo. Among people who finished, the figures were 11.5% (301 people) and 7.3% (106 people). Counting everyone randomized, they were 7.8% and 4.9%. All three gaps were statistically significant.

Significantly more people on the combination lost at least 5% and at least 10% of their starting weight. They also had larger improvements in markers of heart and metabolic disease risk.

The combination was generally well tolerated, but nausea was reported more often than on placebo.

Limits

• The main analysis left out people with no weight check while on the drug and carried forward last on-drug weights. Counting everyone randomized, the gap was smaller (7.8% vs 4.9%).
• Only 301 of the 591 people on the combination and 106 of the 202 on placebo were in the completers analysis.
• Everyone also had an intensive behavior program, so the results apply to the drug used alongside that kind of support.

What it means if you're considering naltrexone

This trial is about weight, not drinking. The naltrexone here is a 32 mg sustained-release form paired with bupropion, so it doesn't show how plain naltrexone tablets for alcohol affect weight. The site's guide to naltrexone and bupropion notes the combination is sold as Contrave and is approved for weight management, not for alcohol or opioid use disorder.