Intended for healthcare professionals


Are cannabinoids an effective and safe treatment option in the management of pain? A qualitative systematic review

BMJ 2001; 323 doi: (Published 07 July 2001) Cite this as: BMJ 2001;323:13
  1. Fiona A Campbell (fiona.campbell{at}, consultant in anaesthetics and pain managementa,
  2. Martin R Tramèr, staff anaesthetistb,
  3. Dawn Carroll, senior research nursec,
  4. D John M Reynolds, consultant clinical pharmacologistd,
  5. R Andrew Moore, consultant biochemistc,
  6. Henry J McQuay, professor of pain reliefc
  1. a Pain Management Centre, Undercroft, South Block, Queen's Medical Centre, Nottingham NG7 2UH
  2. b Division d'Anesthésiologie, Département APSIC, Höpitaux Universitaires, CH-1211 Genève 14, Switzerland
  3. c Pain Research, Nuffield Department of Anaesthetics, The Churchill, Oxford Radcliffe Hospital, Oxford OX3 7LJ
  4. d Department of Clinical Pharmacology, Radcliffe Infirmary, Oxford OX2 6HE
  1. Correspondence to: F A Campbell
  • Accepted 23 March 2001


Objective: To establish whether cannabis is an effective and safe treatment option in the management of pain.

Design: Systematic review of randomised controlled trials.

Data sources: Electronic databases Medline, Embase, Oxford Pain Database, and Cochrane Library; references from identified papers; hand searches.

Study selection: Trials of cannabis given by any route of administration (experimental intervention) with any analgesic or placebo (control intervention) in patients with acute, chronic non-malignant, or cancer pain. Outcomes examined were pain intensity scores, pain relief scores, and adverse effects. Validity of trials was assessed independently with the Oxford score.

Data extraction: Independent data extraction; discrepancies resolved by consensus.

Data synthesis: 20 randomised controlled trials were identified, 11 of which were excluded. Of the 9 included trials (222 patients), 5 trials related to cancer pain, 2 to chronic non-malignant pain, and 2 to acute postoperative pain. No randomised controlled trials evaluated cannabis; all tested active substances were cannabinoids. Oral delta-9-tetrahydrocannabinol (THC) 5-20 mg, an oral synthetic nitrogen analogue of THC 1 mg, and intramuscular levonantradol 1.5-3 mg were about as effective as codeine 50-120 mg, and oral benzopyranoperidine 2-4 mg was less effective than codeine 60-120 mg and no better than placebo. Adverse effects, most often psychotropic, were common.

Conclusion: Cannabinoids are no more effective than codeine in controlling pain and have depressant effects on the central nervous system that limit their use. Their widespread introduction into clinical practice for pain management is therefore undesirable. In acute postoperative pain they should not be used. Before cannabinoids can be considered for treating spasticity and neuropathic pain, further valid randomised controlled studies are needed.

What is already known on this topic

What is already known on this topic Three quarters of British doctors surveyed in 1994 wanted cannabis available on prescription

Humans have cannabinoid receptors in the central and peripheral nervous system In animal testing cannabinoids are analgesic and reduce signs of neuropathic pain Some evidence exists that cannabinoids may be analgesic in humans

What this study adds

What this study adds No studies have been conducted on smoked cannabis

Cannabinoids give about the same level of pain relief as codeine in acute postoperative pain They depress the central nervous system


  • Funding MRT was supported by a PROSPER grant from the Swiss National Research Foundation (No 3233-051939.97). DC was supported by the Royal College of Nursing Institute's Research Assessment Exercise grant.

  • Competing interests None declared. DC is currently employed by Pfizer; the change of employment occurred after the work in this study was completed.

  • Accepted 23 March 2001
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