Extended-release injectable naltrexone for opioid use disorder: a systematic review

Brantley P. Jarvis, August F. Holtyn, Shrinidhi Subramaniam, D. Andrew Tompkins, Emmanuel A. Oga, George E. Bigelow, Kenneth Silverman

Research output: Contribution to journalReview articlepeer-review

73 Scopus citations


Aims: To review systematically the published literature on extended-release naltrexone (XR-NTX, Vivitrol®), marketed as a once-per-month injection product to treat opioid use disorder. We addressed the following questions: (1) how successful is induction on XR-NTX; (2) what are adherence rates to XR-NTX; and (3) does XR-NTX decrease opioid use? Factors associated with these outcomes as well as overdose rates were examined. Methods: We searched PubMed and used Google Scholar for forward citation searches of peer-reviewed papers from January 2006 to June 2017. Studies that included individuals seeking treatment for opioid use disorder who were offered XR-NTX were included. Results: We identified and included 34 studies. Pooled estimates showed that XR-NTX induction success was lower in studies that included individuals that required opioid detoxification [62.6%, 95% confidence interval (CI) = 54.5–70.0%] compared with studies that included individuals already detoxified from opioids (85.0%, 95% CI = 78.0–90.1%); 44.2% (95% CI = 33.1–55.9%) of individuals took all scheduled injections of XR-NTX, which were usually six or fewer. Adherence was higher in prospective investigational studies (i.e. studies conducted in a research context according to a study protocol) compared to retrospective studies of medical records taken from routine care (6-month rates: 46.7%, 95% CI = 34.5–59.2% versus 10.5%, 95% CI = 4.6–22.4%, respectively). Compared with referral to treatment, XR-NTX reduced opioid use in adults under criminal justice supervision and when administered to inmates before release. XR-NTX reduced opioid use compared with placebo in Russian adults, but this effect was confounded by differential retention between study groups. XR-NTX showed similar efficacy to buprenorphine when randomization occurred after detoxification, but was inferior to buprenorphine when randomization occurred prior to detoxification. Conclusions: Many individuals intending to start extended-release naltrexone (XR-NTX) do not and most who do start XR-NTX discontinue treatment prematurely, two factors that limit its clinical utility significantly. XR-NTX appears to decrease opioid use but there are few experimental demonstrations of this effect.

Original languageEnglish (US)
Pages (from-to)1188-1209
Number of pages22
Issue number7
StatePublished - Jul 2018


  • Extended-release
  • heroin
  • injectable
  • medication-assisted treatment
  • naltrexone
  • opioid use disorder
  • prescription opioids

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Psychiatry and Mental health


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