Does family history of alcoholism moderate naltrexone's effects on alcohol use?

Primary outcomes from the COMBINE Study indicated support for naltrexone (Revia) on measures of abstinence and time to heavy drinking; however, effect sizes were modest. The delineation of individual difference variables that qualify these results could aid efforts to target treatment approaches appropriately. Laboratory and clinical studies have found greater effectiveness of naltrexone among men and those with familial alcoholism. The present study used multilevel modeling to investigate family history of alcoholism (FHA) based on first-degree relatives and gender as moderators of naltrexone's effects on three drinking outcomes: percentage of days abstinent, drinks per drinking day, and percentage of heavy drinking days.

Data were drawn from the COMBINE public data set and included the subsample of participants (n = 603) randomized to receive active medication or placebo plus medical management.

We observed a main effect of FHA on drinks per drinking day (B = 2.01, SE = .91, p = .03) such that greater FHA was associated with greater alcohol use per drinking occasion. No other main effects of FHA were observed on drinking outcomes. A significant Naltrexone × Time interaction was observed for percentage of heavy drinking days (B = -1.61, SE = .69, p = .02), consistent with the previously published COMBINE results. No significant Naltrexone × FHA interactions were observed for any of the three outcomes. Gender did not modify these results.

Taken together, these results indicate an effect of FHA on drinking behavior but do not support FHA among first-degree relatives as a moderator of naltrexone's efficacy in this sample.