Summary: Study finds no evidence to suggest cannabis helps patients with opioid use disorder to stop using opioids.
Source: McMaster University
There has been interest in cannabis being used as a replacement drug for people with opioid use disorder, but research at McMaster University has found it doesn’t work.
The research team looked at all research on the effects of cannabis use on illicit opioid use during methadone maintenance therapy, which is a common treatment for opioid use disorder, and found six studies involving more than 3,600 participants.
However, a meta-analysis of the studies found cannabis use didn’t reduce illicit opioid use during treatment nor did it retain people in treatment.
The study was published today in the Canadian Medical Association Journal.
“There is limited evidence that cannabis use may reduce opioid use in pain management, and some high-profile organizations have suggested cannabis is an ‘exit drug’ for illicit opioid use, but we found no evidence to suggest cannabis helps patients with opioid use disorder stop using opioids,” said senior author Dr. Zainab Samaan, associate professor of psychiatry and behavioural neurosciences at McMaster and a Hamilton staff psychiatrist.
Funding: The study was funded by the Canadian Institutes of Health Research.
About this neuroscience research article
Source: McMaster University Media Contacts: Veronica McGuire – McMaster University Image Source: The image is in the public domain.
Cannabis use during methadone maintenance treatment for opioid use disorder: a systematic review and meta-analysis
Background: Rates of cannabis use among patients receiving methadone maintenance therapy are high, and cannabis use may be associated with outcomes of methadone maintenance therapy. We examined the effect of cannabis use on opioid use in patients receiving methadone maintenance therapy to test the hypothesis that cannabis use is associated with a reduction in opioid use. Methods: In this systematic review, we searched MEDLINE/PubMed, Embase, PsycINFO, CINAHL and ProQuest Dissertations and Theses Global from inception to July 12, 2018. We summarized the effects of cannabis use on opioid use during methadone maintenance therapy and treatment retention. We conducted meta-analyses using a random effects model.
Results: We included 23 studies in our review. We performed a meta-analysis of 6 studies, with a total number of participants of 3676, examining use of cannabis and opioids during methadone maintenance therapy. Owing to high heterogeneity, we described the studies qualitatively but provide the forest plots as supplemental material. The overall quality of evidence was very low, with a high risk of bias, owing to the nature of observational studies.
Interpretation: We found no consensus among studies that cannabis use is associated with reduced opioid use or longer treatment retention when used during methadone maintenance therapy in patients with opioid use disorder.