Research demonstrates benefits of medical cannabis as a treatment for chronic pain

MUHC and McGill researchers provide evidence that cannabis may offer relief to patients suffering from chronic neuropathic pain.

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 The medicinal use of cannabis has been debated by clinicians, researchers, legislators and the public at large for many years as an alternative to standard pharmaceutical treatments for pain, which may not always be effective and may have unwanted side effects.

A new study by McGill University Health Centre (MUHC) and McGill University researchers provides evidence that cannabis may offer relief to patients suffering from chronic neuropathic pain. The results of the groundbreaking study are published in the latest issue of the Canadian Medical Association Journal.

“This is the first trial to be conducted where patients have been allowed to smoke cannabis at home and to monitor their responses, daily," says Dr. Mark Ware, lead author of the study, who is also Director of Clinical Research at the Alan Edwards Pain Management Unit at the MUHC and an assistant professor of anesthesia in McGill University’s Faculty of Medicine, and neuroscience researcher at the Research Institute of the MUHC.

In this study, low doses (25mg) of inhaled cannabis containing approximately 10% THC (the active ingredient in cannabis), smoked as a single inhalation using a pipe three times daily over a period of five days, offered modest pain reduction in patients suffering from chronic neuropathic pain (pain associated with nerve injury) within the first few days. The results also suggest that cannabis improved moods and helped patients sleep better. The effects were less pronounced in cannabis strains containing less than 10% THC.

“The patients we followed suffered from pain caused by injuries to the nervous system from post-traumatic (e.g. traffic accidents) or post-surgical (e.g. cut nerves) events, and which was not controlled using standard therapies” explains Dr. Ware. “This kind of pain occurs more frequently than many people recognize, and there are few effective treatments available. For these patients, medical cannabis is sometimes seen as their last hope.”

“This study marks an important step forward because it demonstrates the analgesic effects of cannabis at a low dose over a shot period of time for patients suffering from chronic neuropathic pain,” adds Dr. Ware. The study used herbal cannabis from Prairie Plant Systems (under contract to Health Canada to provide cannabis for research and medical purposes), and a 0% THC ‘placebo’ cannabis from the USA.

However, larger-scale studies with a longer time frame and higher doses of THC are needed to further evaluate the efficacy and long-term safety of medical cannabis. “Our challenge as researchers is to continue to conduct rigorous clinical studies on the medical use of cannabis with strict attention to details such as quality and dosage,” says Dr. Ware. “This will allow us to move the debate forward by providing reliable scientific clinical data.”

Listen to the podcast with Dr. Ware

About the Study

The article “Smoked cannabis for chronic neuropathic pain,” is published in the Canadian Medical Association Journal (www.cmaj.ca) and was made possible by grants from the Canadian Institutes of Health Research (CIHR). Click here for online access: http://www.cmaj.ca/embargo/cmaj091414.pdf

Click here for the related commentary: http://www.cmaj.ca/embargo/cmaj100799.pdf

About the McGill University Health Centre (MUHC) One of the world’s foremost academic health centres, the MUHC offers exceptional and integrated patient-centric care, research and teaching. Highly committed to the continuum of care in its community and affiliated with the Faculty of Medicine of McGill University, The Montreal Children's Hospital, the Montreal General Hospital, the Royal Victoria Hospital, the Montreal Neurological Hospital, the Montreal Chest Institute and the Lachine Hospital of the MUHC value multidisciplinary service throughout the lifespan, innovative technologies and practices, strategic partnerships and leadership in knowledge transfer. The MUHC is currently carrying out a $2.25-billion Redevelopment Project on three campuses—the Mountain, the Glen and Lachine—designed to provide healthcare professionals with an effective environment in which to ensure patients and their families benefit from The Best Care for Life. The campuses are also anchored in best sustainable-development practices, including LEED® and BOMA BESt guidelines. www.muhc.ca www.muhc.ca/construction

The Research Institute of the McGill University Health Centre (RI MUHC) is a world-renowned biomedical and health-care hospital research centre. Research is organized by eleven research axes (or programs). Located in Montreal, Quebec, Canada, the Institute is the research arm of the McGill University Health Centre affiliated with the Faculty of Medicine at McGill University. The Institute supports over 600 researchers, over 1,800 graduate students and post-docs and fellows devoted to a broad spectrum of fundamental and clinical research. Over 1000 clinical research studies are conducted within our hospitals each year. www.muhc.ca/research/

 The Research Institute of the MUHC is supported in part by the Fonds de la recherche en santé du Québec (FRSQ).

About McGill University Founded in Montreal, Que., in 1821, is Canada's leading post-secondary institution. It has two campuses, 11 faculties, 10 professional schools, 300 programs of study and more than 33,000 students. McGill attracts students from more than 150 countries around the world. Almost half of McGill students claim a first language other than English - including 6,000 francophones - with more than 6,800 international students making up almost 20 per cent of the student body. www.mcgill.ca