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Cannabinoids for control of chemotherapy induced nausea and vomiting: quantitative systematic review

BMJ 2001; 323 doi: (Published 07 July 2001) Cite this as: BMJ 2001;323:16
  1. Martin R Tramèr (martin.tramer{at}, staff anaesthetista,
  2. Dawn Carroll, senior research nurseb,
  3. Fiona A Campbell, consultant in anaesthetics and pain managementc,
  4. D John M Reynolds, consultant clinical pharmacologistd,
  5. R Andrew Moore, consultant biochemistb,
  6. Henry J McQuay, professor of pain reliefb
  1. a Division d'Anesthésiologie, Département Anesthésiologie, Pharmacologie Clinique et Soins Intensif de Chirurgie, Hôpitaux Universitaires, CH-1211 Genève 14, Switzerland
  2. b Pain Research, Nuffield Department of Anaesthetics, Churchill, Oxford Radcliffe Hospital, Oxford OX3 7LJ
  3. c Pain Management Centre, Undercroft, South Block, Queen's Medical Centre, Nottingham NG7 2UH
  4. d Department of Clinical Pharmacology, Radcliffe Infirmary, Oxford OX2 6HE
  1. Correspondence to: M R Tramèr
  • Accepted 12 October 2000


Objective: To quantify the antiemetic efficacy and adverse effects of cannabis used for sickness induced by chemotherapy.

Design: Systematic review.

Data sources: Systematic search (Medline, Embase, Cochrane library, bibliographies), any language, to August 2000.

Studies: 30 randomised comparisons of cannabis with placebo or antiemetics from which dichotomous data on efficacy and harm were available (1366 patients). Oral nabilone, oral dronabinol (tetrahydrocannabinol), and intramuscular levonantradol were tested. No cannabis was smoked. Follow up lasted 24 hours.

Results: Cannabinoids were more effective antiemetics than prochlorperazine, metoclopramide, chlorpromazine, thiethylperazine, haloperidol, domperidone, or alizapride: relative risk 1.38 (95% confidence interval 1.18 to 1.62), number needed to treat 6 for complete control of nausea; 1.28 (1.08 to 1.51), NNT 8 for complete control of vomiting. Cannabinoids were not more effective in patients receiving very low or very high emetogenic chemotherapy. In crossover trials, patients preferred cannabinoids for future chemotherapy cycles: 2.39 (2.05 to 2.78), NNT 3. Some potentially beneficial side effects occurred more often with cannabinoids: “high” 10.6 (6.86 to 16.5), NNT 3; sedation or drowsiness 1.66 (1.46 to 1.89), NNT 5; euphoria 12.5 (3.00 to 52.1), NNT 7. Harmful side effects also occurred more often with cannabinoids: dizziness 2.97 (2.31 to 3.83), NNT 3; dysphoria or depression 8.06 (3.38 to 19.2), NNT 8; hallucinations 6.10 (2.41 to 15.4), NNT 17; paranoia 8.58 (6.38 to 11.5), NNT 20; and arterial hypotension 2.23 (1.75 to 2.83), NNT 7. Patients given cannabinoids were more likely to withdraw due to side effects 4.67 (3.07 to 7.09), NNT 11.

Conclusions: In selected patients, the cannabinoids tested in these trials may be useful as mood enhancing adjuvants for controlling chemotherapy related sickness. Potentially serious adverse effects, even when taken short term orally or intramuscularly, are likely to limit their widespread use.

What is already known on this topic

What is already known on this topic Requests have been made for legalisation of cannabis (marijuana) for medical use

Long term smoking of cannabis can have physical and neuropsychiatric adverse effects Cannabis may be useful in the control of chemotherapy related sickness

What this study adds

What this study adds Oral nabilone and dronabinol and intramuscular levonantradol are superior to conventional antiemetics (such as prochlorperazine or metoclopramide) in chemotherapy

Side effects are common with cannabinoids, and although some may be potentially beneficial (euphoria, “high,” sedation), others are harmful (dysphoria, depression, hallucinations) Many patients have a strong preference for cannabinoids


  • Funding MRT received a PROSPER grant (No 32-51939.97) from the Swiss National Science Foundation. DC was supported by the Royal College of Nursing Institute RAE Grant.

  • Competing interests None declared.

  • Accepted 12 October 2000
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