Cannabis for the Management of Pain: Assessment of Safety Study (COMPASS)

doi:10.1016/j.jpain.2015.07.014

The Journal of Pain

Volume 16, Issue 12, December 2015, Pages 1233-1242

https://doi.org/10.1016/j.jpain.2015.07.014 Get rights and content

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Highlights

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Medical cannabis used for chronic pain over one year appears to have a reasonable safety profile.
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The detailed listing of adverse events to medical cannabis will enhance clinical decision-making.
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The average daily dose of dried herbal cannabis used by patients with chronic pain was 2.5g/day.
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Medical cannabis use over one year was associated with improvements in pain, function, quality of life and cognitive function.

Abstract

Cannabis is widely used as a self-management strategy by patients with a wide range of symptoms and diseases including chronic non-cancer pain. The safety of cannabis use for medical purposes has not been systematically evaluated. We conducted a prospective cohort study to describe safety issues among individuals with chronic non-cancer pain. A standardized herbal cannabis product (12.5% tetrahydrocannabinol) was dispensed to eligible individuals for a 1-year period; controls were individuals with chronic pain from the same clinics who were not cannabis users. The primary outcome consisted of serious adverse events and non-serious adverse events. Secondary safety outcomes included pulmonary and neurocognitive function and standard hematology, biochemistry, renal, liver, and endocrine function. Secondary efficacy parameters included pain and other symptoms, mood, and quality of life. Two hundred and fifteen individuals with chronic pain were recruited to the cannabis group (141 current users and 58 ex-users) and 216 controls (chronic pain but no current cannabis use) from 7 clinics across Canada. The median daily cannabis dose was 2.5 g/d. There was no difference in risk of serious adverse events (adjusted incidence rate ratio = 1.08, 95% confidence interval = .57–2.04) between groups. Medical cannabis users were at increased risk of non-serious adverse events (adjusted incidence rate ratio = 1.73, 95% confidence interval = 1.41–2.13); most were mild to moderate. There were no differences in secondary safety assessments. Quality-controlled herbal cannabis, when used by patients with experience of cannabis use as part of a monitored treatment program over 1 year, appears to have a reasonable safety profile. Longer-term monitoring for functional outcomes is needed.

Study registration

The study was registered with www.controlled-trials.com (ISRCTN19449752).

Perspective

This study evaluated the safety of cannabis use by patients with chronic pain over 1 year. The study found that there was a higher rate of adverse events among cannabis users compared with controls but not for serious adverse events at an average dose of 2.5 g herbal cannabis per day.

Key words

Cannabis

safety

chronic pain

adverse events

cohort study

Cited by (0)

: The study was funded by the Canadian Institutes of Health Research (MOL-66262). M.A.W. receives salary support from the FRQS and the Louise and Alan Edwards Foundation and has a research grant to his institution from CanniMed. M.L. is a founding board member of Panag Pharm Inc, a start-up company researching topical non-psychotropic cannabinoids for pain and inflammation, a medical advisor to Abide Therapeutics researching agents to modulate the endocannabinoid system for the treatment of pain, and a co-investigator on a clinical trial sponsored by Prairie Plant Systems. D.E.M. has received speaker's honoraria and/or consulting fees from Pfizer Canada, Eli Lilly Canada Inc, Janssen Pharmaceuticals, and Purdue Pharma Canada. A.B. discloses consultancies or advisory boards to Bedrocan, CanniMed, Jansen, Johnson & Johnson, Lilly, Merck, Mettrum, Pfizer, and Purdue Pharma. T.W., S.S., J.-P.C., A.G., C.O., and J.M.E. report no conflicts.

: Supplementary data accompanying this article are available online at www.jpain.org and www.sciencedirect.com.

¹: Aline Boulanger, MD, Department d'anesthesie, Université de Montreal, Montreal, Quebec, Canada; John M. Esdaile, MD, Division of Rheumatology, University of British Columbia, Vancouver, British Columbia, Canada; Allan Gordon, MD, Division of Neurology, Mount Sinai Hospital and University of Toronto, Toronto, Ontario, Canada; Mary Lynch, MD, Departments of Anesthesia, Psychiatry and Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada; Dwight E. Moulin, MD, Departments of Clinical Neurological Sciences and Oncology, Western University, London, Ontario, Canada; Colleen O'Connell, MD, Department of Physical Medicine and Rehabilitation, Stan Cassidy Centre for Rehabilitation, Fredericton, New Brunswick, Canada.