Cannabis associated with reduced fentanyl exposure in Vancouver study
Patients who used cannabis and underwent opioid agonist therapy in Vancouver had a significantly lower risk of being exposed to fentanyl, according to a study published in Drug and Alcohol Dependence.
However, an addiction specialist told Healio Primary Care that study design flaws limit how the results can be interpreted.
The study took place in Vancouver, which opened a legally supervised drug injection site in 2003. Researchers analyzed data from 819 adults who used drugs and in the past 6 months underwent opioid agonist therapy (OAT) — either methadone, buprenorphine/naloxone, slow-release oral morphine, injectable diacetylmorphine or hydromorphone.
The researchers reported that during baseline interviews with participants, fentanyl was detected in 53% of adults, but the prevalence was lower among those with urine drug tests that were positive for THC (47% vs. 56%, P = 0.028). During the 2-year study, cannabis use was independently associated with a reduced likelihood of being recently exposed to fentanyl (adjusted prevalence ratio = 0.91; 95% CI, 0.83–0.99).
“These findings suggest that cannabis could have a stabilizing impact for many patients on treatment, while also reducing the risk for overdose,” study author M. Eugenia Socías, MD, MSc, a research scientist with the British Colombia Centre on Substance Use and an assistant professor in the department of medicine at the University of British Columbia, said in a press release.
The researchers said they could not establish causal relationship between cannabis use and reduced fentanyl exposure, but the results are “broadly consistent” with other studies that showed intentional cannabis use reduced illegal opioid use, addressed harms from other substances and provided relief from common comorbidities (eg, chronic pain).