Medical Cannabis: The Canadian Physicians’ Perspective

Marijuana-Cannabis-Weed-Bud-GramBy Murray Opdahl, MD, BSPE, CCFP

As of April 1, 2014, Health Canada stopped authorizing use of marijuana in Canada and placed this responsibility on physicians who were not particularly interested in having this responsibility. Currently, physicians can choose to provide a “medical document” that authorizes the patient to obtain marijuana from a licensed producer.

Under the previous system, physicians completed a document that was provided to Health Canada, which would then decide whether to grant a patient an exemption to allow the patient to possess or grow marijuana themselves. There were listed conditions for which a family physician could support a patient’s use of marijuana, but now the decision to provide a medical document to the patient is placed solely on the physician and there are no longer any categories of medical conditions for which it can be prescribed.

Health Canada’s only role currently is to license producers to grow and sell marijuana for medical purposes. In fact, the Health Canada has suggested it does not “endorse” marijuana, which is not an “approved” drug, but “the courts have required reasonable access to a legal source of marijuana when authorized by a physician.”

As it stands, physicians are the sole gatekeepers in authorizing legal access to cannabis for medical reasons. However, due to lack of robust supporting published evidence, personal reasons, and advice from multiple associations, many physicians continue to be reluctant to authorize this remedy. Clearly, more research in the basic science and clinical use of cannabinoids is required to address the fact that society’s demand for this remedy is way ahead of the evidence that is available for safe and effective use of cannabis as a medical treatment.

Medical authorities in Canada have demonstrated resistance to the government’s delegation of responsibility. The College of Family Physicians of Canada realizes that the current Health Canada regulations put family physicians in a difficult position, where they are asked to authorize our patients’ access to a product with little evidence to support its use, and in the absence of regulatory oversight and approval. The CFPC has stated that “Health Canada places family physicians in an unfair, untenable and to a certain extent, unethical position by requiring them to prescribe cannabis in order for patients to obtain it legally.”

The Canadian Medical Association has also consistently opposed Health Canada’s approach, which places physicians in the role of gatekeeper in authorizing access to marijuana. For example, the CMA states that physicians should not feel obligated to authorize marijuana for medical purposes and physicians who choose to authorize marijuana for their patients must comply with their provincial or territorial regulatory College’s relevant guideline or policy.

The CMA has acknowledged the “unique requirements of patients suffering from a terminal illness or chronic disease for which conventional therapies have not been effective and for whom marijuana may provide relief, physicians remain concerned about the serious lack of clinical research, guidance and regulatory oversight for marijuana as a treatment.” But the organization rightfully notes that “marijuana is a complex substance, and there is not sufficient clinical information on clinical safety and efficacy.” The CMA has also provided a list of recommendations, such as not charging the patient for this service, only authorizing in the context of an established patient-physician relationship, as well as reassessing the patient on a regular basis for its effectiveness to address the medical condition and for evaluation of possible addiction and diversion.

At the provincial level, various Colleges of Physicians and Surgeons, which regulate physicians, have created medical cannabis bylaws and guidelines that physicians must comply with.

British Columbia’s College of Physicians and Surgeons position on marijuana for medical purposes is that “few reliable published studies are available on the benefits of marijuana in smoked form…” and “many uncertainties remain about the effects, both beneficial and harmful, of smoked marijuana.” Accordingly, physicians are advised that they should not prescribe any substance for their patients without knowing the risks, benefits, potential complications and drug interactions associated with use of that agent.

In June 2014, the Saskatchewan College of Physicians and Surgeons created a bylaw that regulates physicians’ authorization of medical marijuana. The bylaw specifically acknowledges that there has not been sufficient scientific or clinical assessment to provide evidence about the safety and efficacy of marijuana for medical purposes, even though federal government regulations have authorized use of marijuana for medical purposes.

Clearly, all of these medical entities recommend significant caution in the use of cannabis as a medical treatment. These opinions and recommendations have a direct effect on physicians’ consideration to authorize cannabis for their patients.

Current research

Although most of the research on cannabinoid agents has been carried out on pharmaceutical medications, such as Nabilone capsules (Cesamet) and Nabixolols oral spray (Sativex), there are a number of published randomized controlled trials on herbal or dried cannabis in lessening painful conditions related to HIV neuropathy, neuropathic pain, multiple sclerosis spasticity, and Crohn’s disease.

A number of Canadian physicians involved in the Canadian Pain Society are at the forefront of research on cannabinoids. Dr. Mary Lynch published a systematic review in the 2011 edition of the British Journal of Clinical Pharmacology and came to the following conclusion: “Overall there is evidence that cannabinoids are safe and modestly effective in neuropathic pain with preliminary evidence of efficacy in fibromyalgia and rheumatoid arthritis.”

Dr. Mark Ware, one of Canada’s leading researchers and educators in the area of cannabinoids, has also published two landmark studies on cannabinoids, including a study on “Smoked cannabis for neuropathic pain” (CMAJ 2010) and an additional publication related to the assessment of safety of cannabis over a one year period (APS 2015). In October 2014, Dr. Ware authored an article called “Medical Cannabis and Pain” for the International Association for the Study of Pain (IASP) that provides an excellent overview of this therapeutic area. [1]

Specifically, research into cannabinoid agents suggests they have a role in well-recognized pain management guidelines. And the Canadian Pain Society recently changed its treatment recommendations for neuropathic pain to include cannabinoids as third line agents when other pharmacological and nonpharmacological treatments were not successful or well-tolerated.

For anyone interested in further information related to cannabinoids, I would recommend the Canadian Consortium for the Investigation of Cannabinoids. This nonprofit organization of basic and clinical researchers and healthcare professionals was established to promote evidence-based research and education regarding the endocannabinoid system and therapeutic applications of cannabinoid agents.

Murray Opdahl is a physician in Saskatchewan.

Further reading

Canadian Consortium for the Investigation of Cannabinoids website at www.ccic.net

College of Family Physicians of Canada. Authorizing Dried Cannabis for Chronic Pain or Anxiety. Available at: https://www.cfpc.ca/uploadedFiles/Resources/_PDFs/Authorizing%20Dried%20Cannabis%20for%20Chronic%20Pain%20or%20Anxiety.pdf

[1] Some of the most interesting findings are as follows:

– population-based studies of recreational cannabis use suggest that the toxicity of cannabis is extremely low, although associations are reported between recreational cannabis use and early onset psychosis, myocardial infarction, stroke, impairments in driving, and increased risk of accidents; risks of chronic bronchitis are associated with smoking of herbal cannabis;

– in clinical trials, however, the adverse events associated with cannabinoids are similar in quality and quantity to those of many other conventional centrally acting analgesics, and serious adverse drug reactions to cannabinoids are extremely rare;

– the clinical study of inhaled cannabinoids (through smoking or vaporization) is limited by restricted access to supplies of clinical grade material, lack of intellectual property incentives and concerns that studying the medical benefits of cannabis runs contrary to global antidrug and antismoking strategies. Until such issues are addressed, it is unlikely that we will ever see the sort of large-scale phase III trials needed to definitively establish the efficacy of herbal cannabis;

– given the existing scientific knowledge base around cannabis and cannabinoids, some of which the patient may already know (patients may bring copies of scientific papers to their physicians to argue their case), the response to such patients that there is “not enough information” is disingenuous at best, and at worst, an abnegation of clinical responsibility.

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