October 21, 2019
By Megan Brooks
NEW YORK (Reuters Health) - Medical marijuana appears to have some mitigating effect on opioid use and abuse, but the relationship is far from definitive, according to a meta-analytic review of observational studies.
"There is no doubt opioids are causing a major epidemic and health crisis and looking for alternatives and new receptors that could be used for pain control is extremely important," Dr. Asokumar Buvanendran, co-author of the study and chair of the American Society of Anesthesiologists (ASA) Committee on Pain Medicine, told Reuters Health by phone.
The results were presented October 20 at the ASA annual meeting in Orlando, Florida.
Dr. Buvanendran, vice chair of research at Rush University Medical Center in Chicago, and Mario Moric, a biostatistician at Rush University, found seven relevant studies published from 2010 to 2018.
Five of the studies concluded that medical marijuana may be associated with benefits such as decreased opioid overdose rates, decreased opioid use, improved quality of life and improved pain control. The putative benefits were found to be weak to moderate overall, but statistically significant (Cohen's d = 0.59; P=0.0039).
Specifically, the data suggest a 29% reduction in opioid overdoses in states with medical marijuana and a 44% to 64% reduction in opioid use among chronic pain patients.
The two other studies found no evidence of reduced opioid use overall. One study suggested an increase in pain for a small subset of patients using marijuana who had more comorbidities and were sicker in general.
"Overall the results suggest medical marijuana may provide some benefit in mitigating opioid misuse, but the studies were not randomized controlled trials comparing marijuana to a placebo, which is what we need to determine a true benefit," Moric said in a conference statement.
"Further research is needed to understand the mechanisms and how cannabinoids can be utilized in a safe setting and also looking at long-term effects, not just short-term effects," Dr. Buvanendran added to Reuters Health.
Potential side effects and the fact that these products often aren't regulated also need to be considered. "Patients need to be cautious, even getting marijuana from a dispensary, there are no (U.S. Food and Drug Administration) or quality controls," said Dr. Buvanendran.
The study had no specific funding and the authors made no relevant disclosures.
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