Anton 2011: adding gabapentin to naltrexone in early sobriety

What they tested

Participants were randomly assigned to naltrexone alone (50 mg a day, 50 people), naltrexone 50 mg a day with gabapentin up to 1,200 mg a day added for the first 6 weeks (50 people), or two placebos, dummy pills (50 people), for 16 weeks. Everyone had medical management, regular check-ins with a clinician.

The idea was that gabapentin might ease the poor sleep and unstable mood common in early abstinence, which might respond better to a different medicine than naltrexone, and so help prevent early relapse.

What they found

During the first 6 weeks, the naltrexone-gabapentin group went longer before heavy drinking than the naltrexone-alone group, whose time to heavy drinking was similar to placebo.

In those weeks, the combination group had fewer heavy drinking days than naltrexone alone, and naltrexone alone had more heavy drinking days than placebo. The combination group also had fewer drinks per drinking day than both other groups.

These differences faded over the remaining weeks of the study, after gabapentin was stopped.

Poor sleep was linked to more drinking in the naltrexone-alone group but not in the combination group. A history of alcohol withdrawal was linked to a better response to the combination.

Limits

• With 50 people per group, it was too small to say much about subgroups such as people with poor sleep or past withdrawal.
• Gabapentin was given for only 6 weeks, so the trial can't say whether a longer course would keep the benefit.
• The abstract doesn't report side effects.

What it means if you're considering naltrexone

For someone starting naltrexone, this trial hints that the first weeks may be harder on naltrexone alone, especially for people who sleep badly or have had withdrawal before. Adding gabapentin helped during the weeks it was given, but the gain didn't last once it stopped.

It's also a result where naltrexone alone did no better than placebo in the early weeks. Any decision about combining medicines belongs with a prescriber.