Opioid Resource Center

Opioid Resource Center

October 19, 2018
2 min read

Long-acting naltrexone may help prevent relapse for opioid use disorder

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Image of Maria Sullivan
Maria A. Sullivan

Long-acting injection naltrexone combined with behavioral therapy showed long-term treatment retention that was twice as high as oral naltrexone in opioid-dependent patients following opioid withdrawal, according to study findings published in American Journal of Psychiatry.

“Although extended-release injectable naltrexone was approved by the FDA in 2010 for the prevention of relapse to opioid dependence following opioid detoxification, this study was the first randomized controlled trial that compared the efficacy of long-term treatment of oral naltrexone to extended-release injectable naltrexone,” Maria A. Sullivan, MD, PhD, from the department of psychiatry at Columbia University and New York State Psychiatric Institute, told Healio Psychiatry.

In previous study, long-acting injection naltrexone administered monthly, which eliminates the need for patients to take a daily pill, outperformed placebo in reducing opioid use over 6 months of treatment, according to the researchers. In the current open-label trial, the researchers compared the retention of patients with opioid use disorder treated with long-acting injection naltrexone or oral naltrexone in combination with weekly behavioral therapy over a 24-week treatment period.

Adults with opioid dependence who completed inpatient opioid withdrawal treatment (n = 60) were transitioned to receive oral naltrexone. After categorizing participants by severity of opioid use, the investigators randomly allocated them to continue treatment with a 50-mg daily dose of oral naltrexone (n = 32) or long-acting injection naltrexone (n = 28) for 24 weeks. Participants received the first dose of injection naltrexone (380 mg) before discharge, after which they received monthly doses.

Sullivan and colleagues found that time to dropout was significantly higher among patients receiving long-acting injection naltrexone than those taking oral naltrexone, even when adjusting for the multiple covariates. The results demonstrated that significantly more patients were retained in treatment for 6 months in the long-acting injection naltrexone group than in the oral naltrexone group (57.1 vs. 28.1%; HR = 2.18; 95% CI, 1.07-4.43).

The observed retention rates for those in the injection and oral naltrexone groups were: 85.7% and 62.5% at 4 weeks; 60.7% and 43.8% at 12 weeks; and 57.1% and 28.1% at 24 weeks.

“Limitations of this study included the fact that it was a pilot study conducted with an open-label design (for safety reasons), there was a high rate of screening failures and patients in the oral naltrexone group carried an extra time commitment to collect weekly medication at the clinic,” Sullivan said.

Most adverse events reported by participants were consistent with symptoms of opioid withdrawal and improved over time. Nine serious adverse events occurred, and five participants were removed from study participation.

“Given that post-detoxification outpatient treatment without pharmacotherapy yields poor completion rates, high relapse rates and heightened risk of overdose and death, [long-acting injection] naltrexone may be a viable alternative to prevent relapse in patients seeking treatment for opioid use disorder who do not prefer an agonist approach,” Sullivan and colleagues wrote in the study. “The present data may call into question the current practice by some third-party payers of requiring a failed trial of oral naltrexone before approving [long-acting injection] naltrexone, given the difference in effectiveness and the high risk of a failed treatment with oral naltrexone.” – by Savannah Demko

Disclosure s : Sullivan reports participating in the design and conduct of the study while a full-time faculty member at Columbia University, and participating in manuscript preparation while an employee of Alkermes. Please see the study for all other authors’ relevant financial disclosures.