Nalmefene is a mu- and delta-opioid receptor antagonist and a kappa-opioid receptor partial agonist. Findings from three multi-center trials conducted in Europe, in which patients were instructed to take the medication as needed (i.e., when they felt tempted to drink alcohol), led to nalmefene’s approval in the European Union to reduce alcohol consumption in patients with alcohol dependence, including men who consume more than 60 g (approximately four standard drinks) per day of ethanol or women who consume more than 40 g (approximately three standard drinks) per day (see Box 1 for the definition of a standard drink). In a meta-analysis of 5 RCTs (N=2,567),16 nalmefene treatment was associated with a reduction of 1.65 more binge drinking days/month (95% confidence interval [CI]=0.89−2.41) than placebo at 6 months and 1.60 more binge drinking days/month (95% CI =0.35−2.85) at 1 year. Nalmefene was also associated with a greater reduction in total alcohol consumption [standardized mean difference (SMD), a measure of effect size = −0.20 (95% CI=0.10−0.30), a small effect] at 6 months.16
