A randomized controlled study of the effect of ifenprodil on alcohol use in patients with alcohol dependence

AIM: This prospective, randomized, controlled, rater‐blinded study investigated the effect of G protein‐activated inwardly rectifying potassium (GIRK) channel inhibitor ifenprodil on alcohol use in patients with alcohol dependence. METHODS: The participants were 68 outpatients with alcohol dependence who were assigned to an ifenprodil group (administered 60 mg ifenprodil per day for 3 months) or control group (administered 600 mg ascorbic acid and calcium pantothenate per day for 3 months). The participants completed a questionnaire that included the frequency of alcohol drinking and presence of heavy drinking before the study period (time 1) and 3 months after the start of the study period (time 2). The alcohol use score was calculated using these two items. RESULTS: Valid data were obtained from 46 participants (25 in the ifenprodil group and 21 in the control group). The alcohol use score at time 2 in the ifenprodil group was significantly lower than that in the control group after adjusting for the score at time 1 and some covariates. The intention‐to‐treat analysis of multiply imputed datasets indicated similar results. Group differences in the frequency of alcohol drinking were significant in the multiply imputed datasets but not in 46 participants. The ifenprodil group had a significantly lower rate of heavy drinking at time 2 than the control group. CONCLUSIONS: This study found an inhibitory effect of ifenprodil on alcohol use in patients with alcohol dependence. The results support the hypothesis that GIRK channel inhibitors ameliorate alcohol dependence. TRIAL REGISTRY: This trial was registered in the UMIN clinical trial registry (UMIN000006347).