Cannabis-based medicinal products in arthritis, a painful conundrum

AIMS: The changing medicolegal climate regarding the medicinal use of cannabinoids in New Zealand will increase the likelihood of patients consulting general practitioners (GPs) about these products. Arthritis is a common medical condition for which cannabis-based products are promoted and used; however, doctors' knowledge about the efficacy and safety of these products in the setting of arthritis may be limited. METHODS: We undertook a rapid review of the medical literature on cannabis-based medicinal products in arthritis. RESULTS: Animal studies have identified endocannabinoid pathways in arthritis that are potentially amenable to interventions. One randomised placebo-controlled trial of Sativex® in adults with rheumatoid arthritis has shown some improvements in pain but not in comparison with a standardised pharmacological treatment regimen. Systematic reviews of cannabis-based products in arthritis have determined that there is currently insufficient evidence to recommend cannabis-based medicines for routine clinical use. There were five ongoing registered clinical trials of cannabis-based products in arthritis, the results of which are yet to be reported. CONCLUSIONS: While animal models have identified possible endocannabinoid pathways in arthritis, there is no clear evidence of benefit in humans or comparative efficacy with current treatments. At this stage, there is little evidence to support GPs prescribing cannabis-based medicinal products for arthritis.