Doctors in Canada are asking for better guidance on the appropriate prescribing of medical marijuana.
A new federal program that took effect April 1 has put doctors in charge of deciding whether a patient should be allowed to use cannabis.
However, a commentary published Monday in the Canadian Medical Association Journal points out that physicians have received no advice on how and when to prescribe the drug.
“We therefore urgently need prescribing guidelines to help us understand the evidence, to counsel our patients and to know when and how to prescribe cannabis,” write Meldon Kahan, MD of the Substance Use Service at Toronto’s Women’s College Hospital and Anita Srivastava, MD of St. Joseph’s Health Centre and the University of Toronto.
“Clear indications for its use are neuropathic pain conditions and spasticity”
Under the new rules, medical marijuana can be prescribed as a treatment for any condition.
But Health Canada, along with the Canadian Medical Association and the Federation of Medical Regulatory Authorities of Canada, assert that there is not enough proof of the drug’s safety and efficacy.
According to Dr. Kahan and Dr. Srivastava, scientific evidence is indeed lacking and only five clinical trials on the benefits of smoked marijuana have ever been conducted.
“Based on the limited controlled trials, the only clear indications for its use are neuropathic pain conditions and spasticity associated with multiple sclerosis. It might also be considered for palliative care and for severe biomedical pain conditions such as rheumatoid arthritis,” they write.
Dr. Kahan and Dr. Srivastava believe pharmaceutical cannabinoids should be tried first before prescribing cannabis. There are two such drugs available in Canada: Cesamet (nabilone), a synthetic THC pill, and Sativex (nabiximols), an oral cannabis spray.
“Both are safer and have greater evidence of efficacy than smoked cannabis,” they conclude.
In a separate commentary published on Monday, David Juurlink, MD PhD of Sunnybrook Health Sciences Centre and the University of Toronto argues that the lack of trial data on cannabis should be weighed in light of the known harms of other prescription drugs.
“Many patients are injured or die every year from the medications we prescribe for pain,” explains Dr. Juurlink.
“As physicians, we should not reject cannabis as a medicine simply because it makes us uncomfortable, or invoke concerns about effectiveness and safety without acknowledging that the other drugs we might prescribe carry similar and often much heavier baggage.”