Extended-release naltrexone overlooked in opioid use disorders guideline

The guideline on the management of opioid use disorders by Bruneau and colleagues1 is excellent; however, they omitted monthly injectable naltrexone. The authors did review use of the oral formulation of this opioid antagonist, which they correctly graded as a weak recommendation based on low-quality evidence. In contrast, two recent randomized controlled trials showed that extended-release naltrexone was effective similarly to buprenorphine–naloxone for retention in treatment and reduction in drug use once initiated postdetoxification.2^,3 Importantly, extended-release naltrexone is cost-effective overall4 and can also treat alcohol use disorders.5 Patients taking extended-release naltrexone have no euphoria or physical dependence, which makes it an attractive choice for those with safety-sensitive work.

The US Food and Drug Administration authorized extended-release naltrexone in 2010. The national practice guideline for the treatment of opioid use disorders from the American Society of Addiction Medicine recommends the use of extended-release naltrexone.6 This position is supported by Dr. Nora Volkow, Head of the US National Institute on Drug Abuse.7

Since April 2017, Health Canada has allowed prescription of extended-release naltrexone under a special dispensation for urgent public need.8 Unfortunately, no public funding has been put in place to support this abstinence-based treatment. Bruneau and colleagues note, “The evidence base for pharmacotherapies not yet widely available in Canada, including long-acting and extended-release opioid antagonists … was not reviewed in this guideline.” This omission may dissuade future funding, which would make one of the few proven treatments for opioid use disorders unaccessible to Canadians.