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Extended-release naltrexone comparable to buprenorphine-naloxone for opioid addiction

Extended-release naltrexone had comparable efficacy to a combination of buprenorphine and naloxone for maintaining short-term abstinence from heroin and other illicit substances among opioid-dependent individuals.

“Because of the injection-deterring potential of naloxone hydrochloride and the better safety profile compared with methadone, daily administration of combined buprenorphine and naloxone (buprenorphine-naloxone) is the first choice of [opioid medication treatment] medication in a number of countries. However, the extent to which buprenorphine-naloxone deters injection in practice has been debated,” Lars Tanum, MD, DMSci, of the University of Oslo, Norway, and colleagues wrote.

To compare efficacy of extended-release naltrexone with daily buprenorphine-naloxone for maintaining abstinence from heroin and other illicit substances, researchers conducted a 12-week, multicenter, outpatient, open-label randomized clinical trial at five urban addiction clinics in Norway. Study participants were randomly assigned to receive daily oral flexible dose buprenorphine-naloxone (n = 79) or extended-release naltrexone hydrochloride (n = 80) administered intramuscularly every fourth week for 12 weeks. Participants had a mean age of 36 years.

Retention was comparable between participants who received extended-release naltrexone or buprenorphine-naloxone (difference = –0.1; 95% CI, –0.2 to 0.1), with mean time of 69.3 days and 63.7 days, respectively.

Treatment with extended-release naltrexone was noninferior to buprenorphine-naloxone for group proportion of total number of opioid-negative urine tests (difference = 0.1; 95% CI, –0.04 to 0.2), heroin use (mean difference = –3.2; 95% CI, –4.9 to –1.5) and other illicit substance use (mean difference = –2.7; 95% CI, –4.6 to –0.9).

Superiority analysis indicated significantly lower use of heroin and illicit opioids among participants who received extended-release naltrexone.

There were no other significant differences between treatment groups regarding most other illicit substances.

“Maintaining short-term abstinence from illicit opioids and other substances with extended-release naltrexone was as effective and safe as buprenorphine-naloxone. Extended-release naltrexone should be an available treatment option for opioid-dependent individuals,” the researchers concluded. – by Amanda Oldt

Disclosures: The authors report no relevant financial disclosures.