Canadian Guideline That Arose from Fibromyalgia Study Urges Medical Cannabis Caution

Canadian Guideline That Arose from Fibromyalgia Study Urges Medical Cannabis Caution

A study weighing the risks and benefits of cannabis-based therapies for fibromyalgia has led to University of Alberta researchers developing a guideline to help primary care doctors decide whether to recommend such treatments to their patients.

The team that did the fibromyalgia review concluded that the risk of cannabinoids might outweight the benefits that patients with the disease would receive.

At the moment, the guideline is a proposal. Its creators are seeking feedback on it before coming up with a final version. They published the “Simplified Guideline for Prescribing Medical Cannabinoids in Primary Care” in Canadian Family Physician.

The guideline recommends that, in general, doctors limit their patients’ medical cannabinoid use. But it does suggest that physicians consider the treatment for certain conditions when standard therapies fail.

These include lingering nerve pain, chemotherapy-induced nausea and vomiting, and spasticity from multiple sclerosis or a spinal cord injury. Another use would be to address lingering pain in palliative care, or treatments that relieve symptoms rather than improve a disease.

“While enthusiasm for medical marijuana is very strong among some people, good-quality research has not caught up,” Mike Allan, who led the guideline creation process, said in a press release.

The four uses of medical cannabis that the group reviewed before writing the guideline were relieving pain, nausea and vomiting, spasticity, and treatment side effects.

The pain findings were particularly relevant for patients with fibromyalgia or chronic pain. The researchers discovered that medical cannabis performed better than placebos at alleviating pain, although they considered the quality of the evidence low.

In patients with nerve pain and cancer, cannabinoids reduced chronic pain by 39 percent, versus 30 percent with placebo. In nerve pain alone, the results were 38 percent versus 30 percent. And in palliative pain, they were 30 percent versus 23 percent.

Cannabinoids offered even less pain relief in diseases, the researchers reported. “For pain associated with rheumatologic conditions, three systematic reviews reported insufficient evidence for benefit in fibromyalgia, osteoarthritis, rheumatoid arthritis, and back pain,” they wrote. “Given these findings, and the high risk of harm, the PGC [ Prescribing Guideline Committee ] recommends against cannabinoids for these conditions.”

The guideline team will seek feedback on the proposal from a committee made up of doctors from different disciplines, and from other experts, before sending it to 30,000 doctors across Canada.

Some of those who look at the proposed guideline may be disappointed to learn about the limitations of many medical cannabis studies, the University of Alberta team said. For example, researchers who conducted a number of studies did not randomize patients. In addition, some studies involved few participants, and some didn’t last very long.

“In general we’re talking about one study [per subject], and often very poorly done,” Allan said.

While researchers found evidence that cannabinoids could be beneficial in certain pain-related conditions, they also learned that about 11 percent of patients were unable to tolerate medical cannabinoids. This compared with only 3 percent of those taking placebos.

Another finding was tht 81 percent of people who received medical cannabinoids reported a side effect, compared with 62 percent in the placebo groups. The most common problem was a “central nervous system effect” in 60 percent of the cannabinoid groups, versus 27 percent in the placebo arms, researchers said. Another problem was “sedation,” which 50 percent of the cannabinoid groups reported, versus 30 percent of the placebo groups. Still another was “feeling high” — 35 percent versus 3 percent.

“Better research is definitely needed — randomized control trials that follow a large number of patients for longer periods of time,” Allan said. “If we had that, it could change how we approach this issue and help guide our recommendations.”

The guideline came just days after publication of a special report on what doctors need to consider when prescribing medical cannabis to patients with conditions like fibromyalgia and chronic pain. The report said that the question of whether to prescribe these treatments is still very much open to debate.

Titled “Contemporary Routes of Cannabis Consumption: A Primer for Clinicians,” it appeared in the Journal of the American Osteopathic Association.

It noted concerns about cannabinoids’ potential effect on mental health. The treatments’ active ingredient, tetrahydrocannabinol, led to temporary symptoms of psychosis among healthy volunteers, it said. It is also believed to be a risk factor in developing permanent psychosis, the report added.