Opioid dependence is a growing, worldwide public health concern. In contrast to opioid ?-agonist (or 'substitution') maintenance treatments, injectable extendedrelease naltrexone (XR-NTX), approved in the USA and Russia, is an opioid antagonist, formulated to address nonadherence, which limits the utility of oral naltrexone for opioid dependence. This article reviews the clinical trial data underlying the approval of XR-NTX for opioid dependence and the agent's clinical use. XR-NTX met all primary and secondary end points in a multicenter, placebo-controlled trial (n=250) conducted in Russia, with two discontinuations in each group because of adverse events. Cost-effectiveness analysis of claims data found that 6-month total healthcare costs following XR-NTX (US$8582 per patient) were not significantly different from oral naltrexone (US$8903; p=0.867) or buprenorphine (US$10,049; p=0.414), and were 49% lower than with methadone (US$16,752; p<0.0001). Future research should address induction and duration of treatment with XR-NTX.