Expanding Medical Marijuana Access in Canada: Considerations for the Rheumatologist

Cannabinoids for the treatment of rheumatic diseases - where do we stand?

As medical use of cannabis is increasingly legalized worldwide, a better understanding of the medical and hazardous effects of this drug is imperative. The pain associated with rheumatic diseases is considered a prevalent indication for medicinal cannabis in various countries. Thus far, preliminary clinical trials have explored the effects of cannabis on rheumatoid arthritis, osteoarthritis and fibromyalgia; preliminary evidence has also found an association between the cannabinoid system and other rheumatic conditions, including systemic sclerosis and juvenile idiopathic arthritis. The potential medicinal effects of cannabis could be attributable to its influence on the immune system, as it exerts an immunomodulatory effect on various immune cells, including T cells, B cells and macrophages. However, the available evidence is not yet sufficient to support the recommendation of cannabinoid treatment for rheumatic diseases.

Prevalence, reasons, perceived effects, and correlates of medical marijuana use: A review

BACKGROUND

The use of marijuana for medical purposes is now legal in some U.S. states and other jurisdictions, such as Canada, and Israel. Despite the widespread legalization of medical marijuana globally, there is limited information on patterns and correlates of medical marijuana use (MMU). We conducted a literature review to assess prevalence, reasons, perceived effects, and correlates of MMU among adolescents and adults.

METHODS

We searched peer-reviewed articles in English between January 1996 and August 2016 from several databases (PubMed, Google Scholar, Embase, CINAHL, and PsycINFO) using different combinations of keywords.

RESULTS

A total of 25 articles met the inclusion criteria. In the U.S., national survey estimates of prescribed MMU was 1.1% among 12th graders and 17% among adults who reported past-year marijuana use. The reported prevalence of prescribed MMU ranged from <1.7% in Israeli cancer patients to 17.4% in American health care patients. The reported prevalence of self-medication with marijuana ranged from 15% in Canadian patients with chronic pain to 30% in British patients with multiple sclerosis. Pain was the most frequently endorsed reason for use. MMU appeared to provide symptom relief for a range of pain conditions, sleep disturbance, and anxiety symptoms, but it did not appear to provide sufficient relief of cluster headache symptoms. Non-medical marijuana use was a common factor associated with MMU across studies.

CONCLUSION

Either MMU or self-medication with marijuana was common, mainly due to pain management. Additional research is needed to evaluate temporal and causal associations of non-medical marijuana use with MMU.

Efficacy, tolerability and safety of cannabinoids in chronic pain associated with rheumatic diseases (fibromyalgia syndrome, back pain, osteoarthritis, rheumatoid arthritis): A systematic review of randomized controlled trials

BACKGROUND

In the absence of an ideal treatment for chronic pain associated with rheumatic diseases, there is interest in the potential effects of cannabinoid molecules, particularly in the context of global interest in the legalization of herbal cannabis for medicinal use.

METHODS

A systematic search until April 2015 was conducted in Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, www.cannabis-med.org and clinicaltrials.gov for randomized controlled trials with a study duration of at least 2 weeks and at least ten patients per treatment arm with herbal cannabis or pharmaceutical cannabinoid products in fibromyalgia syndrome (FMS), osteoarthritis (OA), chronic spinal pain, and rheumatoid arthritis (RA) pain. Outcomes were reduction of pain, sleep problems, fatigue and limitations of quality of life for efficacy, dropout rates due to adverse events for tolerability, and serious adverse events for safety. The methodology quality of the randomized controlled trials (RCTs) was evaluated by the Cochrane Risk of Bias Tool.

RESULTS

Two RCTs of 2 and 4 weeks duration respectively with nabilone, including 71 FMS patients, one 4-week trial with nabilone, including 30 spinal pain patients, and one 5-week study with tetrahydrocannbinol/cannabidiol, including 58 RA patients were included. One inclusion criterion was pain refractory to conventional treatment in three studies. No RCT with OA patients was found. The risk of bias was high for three studies. The findings of a superiority of cannabinoids over controls (placebo, amitriptyline) were not consistent. Cannabinoids were generally well tolerated despite some troublesome side effects and safe during the study duration.

CONCLUSIONS

Currently, there is insufficient evidence for recommendation for any cannabinoid preparations for symptom management in patients with chronic pain associated with rheumatic diseases.