Extended-Release Naltrexone for Maintaining Abstinence in Patients with Opioid Use Disorder?

Opioid use disorder (OUD) is a major global public health problem, with overdose rates rising precipitously over the last two decades in the U.S. Conventionally, methadone and buprenorphine-naloxone are used to treat OUD; they also reduce opioid use, overdose, and criminal activity. However, as these treatments are themselves opioids, physical dependence continues, illicit use can occur, and access to treatment can be a major challenge. Naltrexone is an opioid antagonist without these problems, and when given in an extended-release form (ERN; i.e., monthly injections), it increases abstinence compared with placebo. Enthusiasm for its widespread use has been dampened by poor adherence rates. In a noninferiority trial of ERN compared with daily buprenorphine-naloxone, researchers recruited 159 participants with opioid dependence from outpatient or inpatient detoxification centers in Norway.

Buprenorphine-naloxone (mean dose, 11 mg/day; target dose, 16 mg/day) or ERN (380 mg intramuscularly every fourth week) was given for 12 weeks. By the final week, ERN showed somewhat higher, statistically noninferior retention (dropouts: ERN, 24; buprenorphine-naloxone, 29). Treatment outcomes (urine drug tests and self-reported use) with ERN were also noninferior. However, the ERN group had somewhat lower mean past-month opioid use days at baseline (but not years of use and rates of intravenous opioid use), which could have biased results.