Limited evidence supports the role of cannabis in pain relief

The pain-relieving effects of cannabis and related products are based on their ability to mimic the body's own endocannabinoid system, which can affect the sensation of pain. A U.S. federally funded systematic evidence review of 3,000 studies (25 of which had scientifically valid evidence) found that just three products showed evidence providing pain relief: Dronabinol (Marinol) and nabilone (Cesamet), both FDA-approved synthetic products; and nabiximols (Sativex; not available in the United States), a sublingual spray. In the review, researchers sorted products into high, comparable, and low ratios of THC to CBD and compared their reported benefits and side effects. Dronabinol and nabilone, both of which contain 100% tetrahydrocannabinol (THC), showed the strongest benefit among the products studied. Nabiximols contains equal parts THC and cannabidiol (CBD). The review found an otherwise surprising dearth of evidence. "In general, the limited amount of evidence surprised all of us," said lead author Marian S. McDonagh, PharmD, emeritus professor of medical informatics and clinical epidemiology in the OHSU School of Medicine. Read: Extensive online program delves into all things cannabis "We saw only a small group of observational cohort studies on cannabis products that would be easily available in states that allow it, and these were not designed to answer the important questions on treating chronic pain." While 22 states have legalized marijuana (both medical and recreational), few of the products available in dispensaries have been well studied. "For some cannabis products, such as whole-plant products, the data are sparse with imprecise estimates of effect and studies had methodological limitations," the authors wrote in the Annals of Internal Medicine. "Cannabis products vary quite a bit in terms of their chemical composition, and this could have important effects in terms of benefits and harm to patients," said co-author Roger Chou, MD, director of OHSU's Pacific Northwest Evidence-based Practice Center. "The evidence for one cannabis-based product may not be the same for another." The project was funded by Agency for Healthcare Research and Quality of the U.S. Department of Health and Human Services. This article originally appeared in our U.S. sister publication Convenient Care Clinician.

Limited evidence supports the role of cannabis in pain relief

Register for free access or login.

Related Topics