Access to medical cannabis may reduce opioid prescriptions in patients with osteoarthritis, with opioids no longer required in more than one-third of patients after medical cannabis certification, results presented here show.

“We believe that medical cannabis may have a role in the management of chronic pain in the future while simultaneously decreasing our reliance on opioids,” Asif M. Ilyas, MD, MBA, FAAOS, president of the Rothman Opioid Foundation and professor of orthopedic surgery at the Rothman Orthopaedic Institute and Thomas Jefferson University, told Healio. “However, we’re early on the process of understanding medical cannabis. We don’t have a good sense yet, fully, of its long-term outcomes, long-term side effects, best dosages, best frequencies and best concentrations or combinations.”

Using a prescription drug monitoring program system for patients with OA, Ilyas and colleagues compared average morphine milligram equivalents per day of opioid prescriptions filled within 6 months prior to and 6 months after access to medical cannabis. Researchers considered change in opioid prescriptions filled before and after medical cannabis certification and use as the primary study outcome measure. Researchers collected patient outcome measures, including VAS pain score, global mental health quality of life score and global physical health quality of life score, at 3, 6 and 9 months post-medical cannabis certification using the Patient-Reported Outcome Measurement Information System questionnaire. Researchers also collected and analyzed data on route of medical cannabis administration during the 3-to-6-month follow-up visit.

Asif M. Ilyas

Results presented at the American Academy of Orthopaedic Surgeons Annual Meeting showed a significant decrease in average morphine milligram equivalents per day from 18.2 to 9.8 after access to medical cannabis. Researchers found an average drop in morphine milligram equivalents per day of 46.3%, while 37.5% of patients dropped to 0 morphine milligram equivalents per day. Researchers noted a significant decrease in pain scores from 6.6 to 5 at 3-month follow-up and to 5.4 at 6-month follow-up, while the global physical health score increased significantly from 37.5 to 41.4 by 3-month follow-up.

Researchers identified vaporized oil, vaporized flower, oral, topical and sublingual tincture as the various routes of medical cannabis administration. Among 33 patients who had data on route of medical cannabis administration, results showed 63.6% used a single route of administration, 33.3% used two routes and 3% used three routes. Researchers found 66.7% of patients used sublingual tincture as the route of medical cannabis administration, 33.3% used a topical administration route, 21.2% used vaporized oil, 9.1% used an oral administration route and 9.1% used vaporized flower.