Article Text

Original research
Cannabis for medical use versus opioids for chronic non-cancer pain: a systematic review and network meta-analysis of randomised clinical trials
  1. Haron M. Jeddi1,
  2. Jason W. Busse1,2,3,
  3. Behnam Sadeghirad1,2,3,
  4. Mitchell Levine1,4,5,6,7,
  5. Michael J. Zoratti1,
  6. Li Wang2,3,
  7. Atefeh Noori1,8,
  8. Rachel J. Couban2,
  9. Jean-Eric Tarride1,6,7
  1. 1Department of Health Research Methods, Evidence, and Impact (HEI), Department of Health Research Methods, Evidence, and Impact (HEI), McMaster University, Ontario, Canada
  2. 2Department of Anesthesia, McMaster University, Hamilton, Ontario, Canada
  3. 3Michael G. DeGroote Institute of Pain Research and Care, McMaster University, Hamilton, Ontario, Canada
  4. 4Department of Medicine, McMaster University, Hamilton, Ontario, Canada
  5. 5Division of Clinical Pharmacology and Toxicology, St. Joseph's Healthcare, Hamilton, Ontario, Canada
  6. 6Center for Health Economics and Policy Analysis (CHEPA), McMaster University, Hamilton, Ontario, Canada
  7. 7Programs for Assessment of Technology in Health (PATH), The Research Institute of St. Joe's Hamilton, St. Joseph's Healthcare, Hamilton, Ontario, Canada
  8. 8Hand Program, Division of Plastic, Reconstructive and Aesthetic Surgery, University Health Network, University of Toronto, Toronto, Ontario, Canada
  1. Correspondence to Haron M. Jeddi; markjeddi{at}


Objective The objective of this study is to evaluate the comparative benefits and harms of opioids and cannabis for medical use for chronic non-cancer pain.

Design Systematic review and network meta-analysis.

Data sources EMBASE, MEDLINE, CINAHL, AMED, PsycINFO, PubMed, Web of Science, Cannabis-Med, Epistemonikos and the Cochrane Library (CENTRAL) from inception to March 2021.

Study selection Randomised trials comparing any type of cannabis for medical use or opioids, against each other or placebo, with patient follow-up ≥4 weeks.

Data extraction and synthesis Paired reviewers independently extracted data. We used Bayesian random-effects network meta-analyses to summarise the evidence and the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach to evaluate the certainty of evidence and communicate our findings.

Results Ninety trials involving 22 028 patients were eligible for review, among which the length of follow-up ranged from 28 to 180 days. Moderate certainty evidence showed that opioids provide small improvements in pain, physical functioning and sleep quality versus placebo; low to moderate certainty evidence supported similar effects for cannabis versus placebo. Neither was more effective than placebo for role, social or emotional functioning (all high to moderate certainty evidence). Moderate certainty evidence showed there is probably little to no difference between cannabis for medical use and opioids for physical functioning (weighted mean difference (WMD) 0.47 on the 100-point 36-item Short Form Survey physical component summary score, 95% credible interval (CrI) −1.97 to 2.99), and cannabis resulted in fewer discontinuations due to adverse events versus opioids (OR 0.55, 95% CrI 0.36 to 0.83). Low certainty evidence suggested little to no difference between cannabis and opioids for pain relief (WMD 0.23 cm on a 10 cm Visual Analogue Scale (VAS), 95% CrI −0.06 to 0.53) or sleep quality (WMD 0.49 mm on a 100 mm VAS, 95% CrI −4.72 to 5.59).

Conclusions Cannabis for medical use may be similarly effective and result in fewer discontinuations than opioids for chronic non-cancer pain.

PROSPERO registration number CRD42020185184.

  • Pain management
  • Neurological pain
  • Back pain

Data availability statement

Data are available upon reasonable request.

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See:

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Data availability statement

Data are available upon reasonable request.

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  • Contributors HMJ, JWB, BS, ML and JET conceived and designed the study. HMJ, LW, AN and RJC acquired the data. HMJ, JWB, BS and MJZ contributed to the statistical analyses. HMJ performed the statistical analyses. All authors interpreted the data and could access data included in the study. HMJ, JWB and JET drafted the manuscript. All authors made critical revisions to the article for important intellectual content and gave final approval for the article. HMJ guarantor of work.

  • Funding Parts of this study were supported by grant 119801 and FRN 147994, Co-PIs: JWB and MA Ware from the Canadian Institutes of Health Research and grant 1516-HQ-000017 from Health Canada. JWB is supported, in part, by a Canadian Institutes of Health Research Canada Research Chair in Prevention & Management of Chronic Pain.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.