Public Release: 

Cannabis on trial

McGill University

McGill Pain Centre to examine effects of cannabis on neuropathic pain in world-first study

The potential benefits of smoked cannabis as a pain-reliever will soon be examined by a group of McGill researchers. The University announced today that the McGill Pain Centre* would conduct a one-year pilot study of smoked cannabis for chronic neuropathic pain at the Montreal General Hospital site of the McGill University Health Centre.

Funded through a $235,000 grant, the study is being launched to better understand the prospective therapeutic uses of cannabis and is being supported by Health Canada in partnership with the Canadian Institutes of Health Research (CIHR)*. As the first study to emerge from the Health Canada/CIHR Medical Marijuana Research Program, trial results will eventually help contribute to the development of health policy to address the medical use of marijuana and cannabinoids.

"Today's announcement is an historic step forward in the Government of Canada's plan to conduct research on the potential health benefits of marijuana," says Federal Health Minister Allan Rock. "The grant we are announcing today is the first-ever clinical trial related to medical marijuana to be funded by Health Canada under the Health Canada/CIHR Medical Marijuana Research Program and furthers our compassionate effort to ascertain the potential of marijuana to provide therapeutic benefit to Canadians."

Adds CIHR President, Dr. Alan Bernstein: "Health Canada and CIHR together have recognized the need for research into marijuana and associated cannabinoids, to determine their safety and efficacy in the management of symptoms in patients unresponsive to usual treatment methods. This initiative will address the clinical treatment of such patients with smoked and non-smoked marijuana and cannabinoids to improve our understanding of the safety and efficacy of using cannabinoids to control their symptoms."

A first of many kinds

The McGill Pain Centre's study will also be the world's first peer-reviewed clinical trial examining the effects of smoked cannabis in a non-HIV or Multiple Sclerosis population. While other studies have tested the effects of cannabis constituents on pain, this will be the first trial in which participants will smoke the substance as outpatients.

The trial will be conducted by five McGill scientists working in several fields at the McGill University Health Centre, including lead researcher Dr. Mark Ware, who is also an assistant professor of anesthesia at McGill University. Study collaborators will include Gary Bennett, recently appointed as pain research director of the McGill Pain Centre, psychologist Ann Gamsa, biostatistician Stan Shapiro and epidemiologist Jean-Paul Collet.

"The McGill Pain Centre has designed this study to mirror, as much as possible, the real-life conditions under which patients can currently use cannabis," says Ware, noting trial conditions and outcomes will be based on patients' reported experiences.

The main hypothesis of the study is that herbal cannabis containing 8 percent tetrahydrocannabinol (THC) is superior to cannabis containing lower concentrations of THC in reducing chronic neuropathic pain. THC is the ingredient that causes cannabis "high," which researchers suspect may also have beneficial effects on pain management. "One objective is to discover how much cannabis is needed to obtain pain relief and whether this amount produces any side effects," says Ware.

The McGill Pain Centre will recruit 32 patients for its cannabis study. Each patient will be followed for four weeks to evaluate four strains of cannabis. Patients will smoke a small amount of the herbal material in a single inhalation, using a pipe, according to a dosing schedule. The first dose of each period will be administered under observation at the McGill Pain Centre, with remaining doses self-administered on an outpatient basis.

The quality and intensity of pain will be assessed using the world-renowned McGill Pain Questionnaire, originally developed by McGill psychologist Ronald Melzack. Although this cannabis study is expected to take one year to complete, Ware cautions, this initial step will likely be the first among several before Canadian doctors can begin prescribing marijuana to patients. "It's important to remember that this is a pilot study and the information we gather will help us design larger and more conclusive studies in the future," he says.

The principal objectives of the study are to:

  • Examine the effects of short-term, low-dose, smoked herbal cannabis on pain intensity in patients with chronic neuropathic pain.
  • Study issues of safety, placebo discernment, and dose estimation for clinical effects.
  • Examine the effects of cannabis on quality of life and mood in patients.
  • Evaluate mechanisms of action of cannabinoids on neuropathic pain using quantitative sensory testing.
  • Supply experience and data for the design of a larger clinical trial.

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*The McGill Pain Centre, which is based at the McGill University Health Centre, was founded in 1976. The Centre's mandate is to investigate different ways of relieving chronic pain among its patients.

*The CIHR is Canada's premier agency for health research. Its objective is to excel, according to internationally accepted standards of scientific excellence, in the creation of new knowledge and its translation into improved health for Canadians, more effective health services and products and a strengthened health care system.

Contact: Chantal Beauregard, media relations officer, McGill University Health Centre, 514-843-1560, chantal.beauregard@muhc.mcgill.ca
Source: Sylvain-Jacques Desjardins, communications officer, University Relations Office, 514-398-6752, sylvaind@uro.mcgill.ca
Andrew Matejcic, CIHR Communications, 613-954-7143, AMatejcic@cihr.ca

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