Study: Medical Cannabis Authorizations Correlated with Reduced Use of Opioids

Alberta, Canada: Medical cannabis patients reduce their use of opioids at rates greater than matched controls, according to longitudinal data published in the journal BMC Public Health.

Researchers affiliated with the University of Alberta and the University of Toronto assessed the relationship between medical cannabis use and opioid intake in a cohort of 30,000 chronic opioid users. Over 5,300 of the study participants were authorized by their physicians to use medical cannabis while the remaining subjects served as controls. Investigators evaluated changes in the weekly average oral morphine equivalent (OME) of opioid drugs for medical cannabis patients relative to controls during the 26 weeks before and during the 52 weeks after patients received their authorizations.

They reported, “Among those prescribed high doses of opioids (OME > 100), there were significant reductions in opioid consumption” relative to matched controls. By contrast, those subjects prescribed lower doses of opioids prior to receiving their medical cannabis authorizations failed to show a statistically significant reduction in their opioid intake relative to controls. 

Authors concluded: “This short-term analysis on this population-based study of patients in Alberta, Canada showed that authorization for medical cannabis had intermediate effects on weekly OME in adults prescribed chronic opioids treatment, which was dependent on initial opioid dose. … Greater observations of changes in OME appear to be in those patients who were on a high dosage of opioids (OME > 100). … Overall, our findings may contribute ongoing evidence for clinicians regarding the potential impact of medical cannabis to reduce the opioid burden among patients.”

Full text of the study, “Opioid use in medical cannabis authorization for adult patients from 2013 to 2018: Alberta, Canada,” appears in BMC Public Health. Additional information on the relationship between cannabis and opioid use patterns is available from the NORML fact sheet, “Relationship between Marijuana and Opioids.”