Naltrexone, an efficacious medication for alcohol dependence, does not work for everyone. Symptoms (e.g. insomnia, mood instability), most evident during early abstinence, might respond better to a different pharmacotherapy. Gabapentin may reduce these symptoms and early relapse. This clinical trial evaluated whether gabapentin, in conjunction with naltrexone, was better than naltrexone alone and/or placebo during the early drinking cessation phase (first six weeks) and whether this effect persisted.
A total of 150 alcohol-dependent individuals randomly received sixteen weeks of naltrexone alone (50 mg/day [N= 50]), with gabapentin (up to 1200 mg/day [N=50] for the first six weeks), or double placebo (N= 50) while receiving medical management.
During the first six weeks, the naltrexone/gabapentin group had 1) a longer delay to heavy drinking than the naltrexone-alone group (p =0.04) which was similar to the placebo group, 2) had less heavy drinking days than the naltrexone-alone group (p= 0.0002) which did worse than placebo, and 3) had less drinks/drinking day than the naltrexone-alone group (p=0.02) and the placebo group (p=0.01). These differences faded over the remaining study weeks. Poor sleep was associated with more drinking in the naltrexone-alone group, but not in the combined group, while an alcohol withdrawal history was associated with better response in the combined group.
The addition of gabapentin to naltrexone improved drinking outcomes over naltrexone alone during the first six weeks after cessation of drinking. This effect did not endure once gabapentin was discontinued. Future studies should evaluate gabapentin alone and over longer durations of treatment.