Canadian Rheumatology Association (CRA) Position Statement on Medical Cannabis Use in Rheumatic Disease
|Frequently Asked Questions|
Canadians are increasingly turning to their physicians for guidance regarding medical cannabis use, which has already entered mainstream medicine. Furthermore, the Cannabis Act, legalizing the recreational use of cannabis, came into force across Canada on October 17, 2018. Cannabis is therefore now more freely available and this position statement is intended to provide guidance to physicians so they can offer pragmatic advice to their patients in a caring and empathetic way to ensure harm reduction.
The CRA’s message to people living with rheumatic disease is clear: if a patient is considering using cannabis as part of treatment, or if they are already doing so and have not previously informed their physician, please have a discussion. This ensures patients are aware of the potential risks and benefits of such a decision, and also ensures physicians are aware of patient decisions as it could have implications for future treatment options.
The position statement was developed by a core group including the Chair of the Therapeutics Committee, Chair of the Guidelines Committee, a fellow in rheumatology and an international advisor and reviewed and approved by the CRA Board of Directors. The core group was identified after consultation with both the Therapeutics and the Guidelines committees. The position statement was developed and then circulated to the members of the Therapeutics committee who provided input, then modified according to the input and finally approved by the Therapeutics Committee before submission to the Board. This position statement was developed independently by the CRA to provide guidance to physicians so they can offer pragmatic advice to their patients regarding the potential benefits and risks of cannabis in a caring and empathetic way to ensure harm reduction. Any and all financial support for this initiative was provided by the CRA.
There are no data available on the use of cannabis, medical or recreational, among Canadians living with rheumatic disease. However, 2013 data highlights ‘severe arthritis’ as the most common reason for Health Canada to approve the use of medical cannabis. It is important that people understand that medical cannabis is not an alternative to standard care for any rheumatic disease, and rheumatologists should adhere to current treatment standards and guidelines.
There is a lack of published clinical studies on the effects of cannabis in people living with rheumatic diseases. However, preclinical evidence (i.e., animal studies) suggests that cannabidiol is the molecule with considerable potential to reduce pain and inflammation. By contrast, THC is known as the molecule with psychoactive properties that could have a negative impact on cognitive and psychomotor function, potentially putting a patient at risk for side effects. Concentrations are yet to be studied and identified, and it is possible that it is a combination of the two molecules (THC and CBD) that may have greater impact on symptoms.
There is a lack of published clinical studies on the effects of cannabis in people living with rheumatic diseases. What we do know is that THC is the compound in cannabis primarily responsible for the psychoactive effects – feeling ‘high’ – and includes a sense of euphoria, slower reaction times, memory loss and coordination problems. CBD is well tolerated, even in large doses. Both have been reported to help alleviate pain.
We have used the directive of Health Canada regarding the maximum dose.
Unfortunately, there is a lack of published clinical studies on the effects of cannabis in people living with rheumatic diseases and that includes those taking standard medications for these conditions. There is no study of the interaction of the drugs we use to treat rheumatic diseases and medical cannabis. There is however preclinical evidence in animal studies that cannabis is associated with reduced need for opioids in experimental pain in animals. There is also patient report that cannabis allows patients to reduce their use of opioids, but formal study of this effect is still needed.
If a patient is considering using cannabis as part of any treatment, or if they are already doing so and have not previously informed their physician, it is important to have that discussion with all health care professionals involved. The goal of the position statement is to ensure rheumatologists can offer pragmatic advice to their patients regarding the use and potential risks of cannabis in a caring and empathetic way to ensure harm reduction.
There is only one small trial currently being conducted in Canada that is listed on clinicaltrials.gov, evaluating vapourized cannabis in patients with osteoarthritis of the knee. The lack of evidence regarding the potential use and risks of medical cannabis use by Canadians living with rheumatic disease severely limits the ability of rheumatologists to provide anything more than pragmatic advice to their patients and is an ongoing concern to the Association.