pubmed.ncbi.nlm.nih.gov

Adverse effects of medical cannabinoids: a systematic review - PubMed

  • ️Tue Jan 01 2008

Review

Adverse effects of medical cannabinoids: a systematic review

Tongtong Wang et al. CMAJ. 2008.

Abstract

Background: The therapeutic use of cannabis and cannabis-based medicines raises safety concerns for patients, clinicians, policy-makers, insurers, researchers and regulators. Although the efficacy of cannabinoids is being increasingly demonstrated in randomized controlled trials, most safety information comes from studies of recreational use.

Methods: We performed a systematic review of safety studies of medical cannabinoids published over the past 40 years to create an evidence base for cannabis-related adverse events and to facilitate future cannabis research initiatives. We critically evaluated the quality of published studies with a view to identifying ways to improve future studies.

Results: A total of 321 articles were eligible for evaluation. After excluding those that focused on recreational cannabis use, we included 31 studies (23 randomized controlled trials and 8 observational studies) of medical cannabis use in our analysis. In the 23 randomized controlled trials, the median duration of cannabinoid exposure was 2 weeks (range 8 hours to 12 months). A total of 4779 adverse events were reported among participants assigned to the intervention. Most (4615 [96.6%]) were not serious. Of the 164 serious adverse events, the most common was relapse of multiple sclerosis (21 events [12.8%]), vomiting (16 events [9.8%]) and urinary tract infection (15 events [9.1%]). The rate of nonserious adverse events was higher among participants assigned to medical cannabinoids than among controls (rate ratio [RR] 1.86, 95% confidence interval [CI] 1.57-2.21); the rates of serious adverse events did not differ significantly between these 2 groups (RR 1.04, 95% CI 0.78-1.39). Dizziness was the most commonly reported nonserious adverse event (714 events [15.5%]) among people exposed to cannabinoids.

Interpretation: Short-term use of existing medical cannabinoids appeared to increase the risk of nonserious adverse events. The risks associated with long-term use were poorly characterized in published clinical trials and observational studies. High-quality trials of long-term exposure are required to further characterize safety issues related to the use of medical cannabinoids.

PubMed Disclaimer

Figures

None

Figure 1: Retrieval and selection of studies of safety of cannabinoid preparations.

None

Figure 2: Incidence rates and rate ratios (random-effects model) for nonserious adverse events among participants assigned to medical cannabinoid therapy or control in 23 randomized controlled trials. Dotted vertical line represents no difference between the intervention and the control. CI = confidence interval.

Comment in

Similar articles

Cited by

References

    1. World drug report. New York: United Nations, Office on Drugs and Crime; 2007.
    1. Mechoulam R. The pharmacohistory of Cannabis sativa. In: Mechoulam R, editor. Cannabinoids as therapeutic agents. Boca Raton (FL): CRC Press; 1986. p. 1-19.
    1. Beaulieu P, Ware M. Reassessment of the role of cannabinoids in the management of pain. Curr Opin Anaesthesiol 2007;20:473-7. - PubMed
    1. Marihuana Medical Access Regulations, SOR/01-227, 2001. Available: http://laws.justice.gc.ca/en/C-38.8/SOR-2001-227/text.html (accessed 2008 Mar 26).
    1. Publication of the regulations amending the Marihuana Medical Access Regulations (MMAR). Ottawa: Health Canada; 2005 Sep 14. Available: www.hc-sc.gc.ca/dhp-mps/pubs/precurs/mmar-ramm_e.html (accessed 2008 Mar 26).

Publication types

MeSH terms

Substances