Murphy CE, Wang RC, Montoy JC, et al. - By analyzing relevant blinded randomized placebo-controlled trials in this systematic review and random effects meta-analysis, researchers estimated the impact of extended-release naltrexone vs placebo on alcohol intake in patients suffering from alcohol use disorder (AUD). They also performed pre-planned subgroup analyses to determine if being abstinent when starting treatment (lead-in abstinence) or the span of treatment improves treatment efficacy. They analyzed 7 trials assessing overall 1500 adults with AUD receiving monthly injections of either placebo or extended-release naltrexone at doses of 150-400mg for 2-6 months and some form of behavioral therapy. They found that reduction in drinking days as well as heavy drinking days per month was conferred by extended-release naltrexone, relative to placebo. Longer duration of treatment provided larger reductions.