Canadian multicenter study examines safety of medical cannabis in the treatment of chronic pain

Canadian multicenter study examines safety of medical cannabis in the treatment of chronic pain

A Canadian research team led by Dr. Mark Ware from the Research Institute of the McGill University Health Centre (RI-MUHC) in Montréal has completed a national multicentre study looking at the safety of medical cannabis use among patients suffering from chronic pain. They found that patients with chronic pain who used cannabis daily for one year, when carefully monitored, did not have an increase in serious adverse events compared to pain patients who did not use cannabis. The results, which have been published online in The Journal of Pain, will serve as a benchmark study on the side effects of cannabis when used in pain management.

"This is the first and largest study of the long term safety of use by patients suffering from ever conducted," says lead author, Dr. Ware, specialist at the Montreal General Hospital of the MUHC and associate professor in Family Medicine and Anesthesia at McGill University. "We found that medical cannabis, when used by patients who are experienced users, and as part of a monitored treatment program for chronic pain over one year, appears to have a reasonable safety profile."

As part of the Cannabis for the Management of Pain: Assessment of Safety Study (COMPASS), that started in 2004, the researchers followed 215 adult patients, with chronic non-cancer pain, who used medical cannabis, and compared them to a control group of 216 who were not cannabis users. The study involved seven centres with expertise across Canada located in Fredericton, Halifax, London, Montreal (two sites), Toronto and Vancouver.

The cannabis users were given access to herbal cannabis containing 12.5 per cent THC from a licensed cannabis producer. Cannabis was dispensed through the hospital pharmacy at each site, and patients collected their supply every month after completing the necessary visits and tests. Along with information on adverse effects, subjects underwent lung function and cognitive testing, and were asked about their pain, mood and quality of life over the one year of follow up. A number of the subjects underwent complete panels of blood tests for routine biochemistry, liver and kidney function, and selected hormone levels. The average amount of cannabis used overall was 2.5 grams per day whether smoked, vaporized or taken as edibles.

"Our data show that daily cannabis users had no greater risk than non-users (control group) to experience serious adverse events,'' Dr. Ware who is also a researcher from the Brain Repair and Integrative Neuroscience Program at the RI-MUHC. ''We found no evidence of harmful effects on cognitive function, or blood tests among cannabis consumers and we observed a significant improvement in their levels of pain, symptom distress, mood and quality of life compared to controls. ''

However, the researchers did report an increased risk of non-serious in medical consumers such as headache, nausea, dizziness, somnolence, and respiratory problems associated with smoking.

"It is important to note the limitations of the study," adds Dr. Ware. "Patients were self-selected, not randomized, and most were experienced users. So what we are seeing is that it appears to be a relatively safe drug when used by people who have already determined that it helps them. We cannot draw conclusions about safety issues of new ".

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Provided by McGill University Health Centre
Citation: Canadian multicenter study examines safety of medical cannabis in the treatment of chronic pain (2015, September 29) retrieved 19 February 2019 from
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Sep 30, 2015
I've been a chronic pain patient in the PNW US at several of the best clinics for over a decade. I've tried modern medicines pain treatments and procedures. I've also suffered the side MANY side effects to these treatments.
I started and using Medical Marijuana in 2002, at that time I had little hope for any of the alternative medicine pain treatments. I soon learned that many of the alternative methods like acupuncture, biofeedback, meditation and Medical Marijuana to had very few if any SIDE EFFECTS!
I would have NEVER seen myself being one of those people saying that MARIJUANA SAVED MY LIFE but I have no choice.
I have also had NO CHOICE but to hide it's use to this very day!
I now try to teach other Pain Patients Patients how to avoid the many conflicts that the use of marijuana can and will cause most any US pain patient that still needs real pain doctors of pain medications. The first rule is to never forget THAT WE ARE ALL STILL CRIMINALS UNDER US FEDERAL LAW!

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