Caution urged over prescribing marijuana

EDMONTON — A new medical guideline suggests family doctors should think twice before prescribing medical marijuana.

The Simplified Guideline for Prescribing Medical Cannabinoids in Primary Care, published this week in the medical journal Canadian Family Physician, says there is limited evidence to support the reported benefits of medical marijuana for many conditions.

It adds that any benefit could be balanced or even outweighed by the potential harm.

“While enthusiasm for medical marijuana is very strong among some people, good quality research has not caught up,” project leader Mike Allan, director of evidence-based medicine at the University of Alberta, said in a statement.

The guideline was created by a committee of 10 researchers after an in-depth review of clinical trials. It was peer reviewed by 40 others, including doctors, pharmacists, nurses and patients.

They looked at medical marijuana for treatment of pain, muscle tightness and stiffness, and nausea and vomiting, as well as at its side-effects.

The committee found acceptable research for use of medical marijuana for some conditions including nerve pain, palliative cancer pain, muscle stiffness related to multiple sclerosis or spinal cord injury, and nausea and vomiting from chemotherapy.

Allan said the benefits were generally minor. “Medical cannabinoids should normally only be considered in the small handful of conditions with adequate evidence and only after a patient has tried a number of standard therapies,” he said.

The researchers suggested pharmaceuticals derived from cannabis be tried before smoked marijuana to control dosage. The committee also found that side-effects — including sedation, dizziness and confusion — were common and consistent.

Jonathan Zaid, executive director of patient advocacy group Canadians for Fair Access to Medical Marijuana, said: “There have been many who have reviewed this same evidence and found different outcomes. It’s important to consider all available options.”

He suggested medical cannabis is working for more than 200,000 Canadians.

“The government’s own recent cannabis survey found that 97 per cent of people who said they use cannabis for medical purposes found they were finding effective symptom management,” he said.

The guideline, which isn’t mandated, will be distributed to about 30,000 doctors across Canada.