Authors: Alice Weatherston
Findings from a multisite, randomized trial led by the University of Pennsylvania (PA, USA) and published recently in the New England Journal of Medicine have revealed that once-a-month naltrexone may be more effective in treating opioid addiction than current common treatment modalities.
Currently, prevention of relapse in opioid addicts mainly involves administration of once-a-day methadone or suboxone, which are agonists of opioid receptors much like heroin. Concerns have been raised about their long-term advantages, with many believing that methadone purely provides a replacement addiction.
Naltrexone, which is an opioid receptor antagonist, has therefore recently received increasing attention within the field, despite limited studies on its effectiveness to date.
In the current study, Charles O’Brien (University of Pennsylvania), Joshua Lee (New York University, NY, USA) and colleagues recruited 153 ex-prisoner heroin addicts in the 6 month trial of extended-release naltrexone, as well as 155 other individuals to make up a control group receiving counseling and community treatment programs.
The naltrexone group received monthly injections over the 24 week period and were routinely monitored and followed up along with the control group.
Whilst on naltrexone, the effects of heroin are blocked. Results highlighted a significantly reduced relapse rate in the naltrexone group in comparison to the control group, 43% and 64% respectively, as well as an increased median time to relapse, 10.5 vs 5 weeks.
In addition, no individuals on the naltrexone regime suffered overdoses, even up to 18 months following the end of treatment. In contrast, some members of the control group did experience overdosing.
The findings help to further support the use of antagonist drug treatments as an alternative therapy for opioid addiction, particularly in reducing relapse rate in high-risk individuals.
O’Brien commented on the research implications: “if someone is scheduled to get out of prison with a history of opioid addiction, you could give them one injection, and at least for the next month, they cannot relapse. Normally, they relapse the same day.”
Further research is needed in order to fully understand the long-term effectiveness of naltrexone, however the suggested efficacy of this alternative to standard treatments provides new options for clinicians.
“If you have high blood pressure, we have at least eight or 10 different medications that can be used. Some work better than others for each person. So it’s nice to have several choices for heroin addiction treatment,” remarked O’Brien.