Wang and colleagues performed a systematic review of safety studies of medical cannabinoids published over the past 40 years and found that short-term use appeared to increase the risk of non-serious adverse events. Of all non-serious adverse events, dizziness was the most common (15.5%).

"We found that the rate of non-serious adverse events was 1.86 times higher among medical cannabinoid users than among controls," state the authors. "However, we did not find a higher incidence rate of serious adverse events associated with medical cannabinoid use." The authors note that 99% of the serious adverse events from randomized controlled trials were reported in only 2 trials, a fact the authors say suggests that more studies are required to further characterize safety issues.

In a related commentary, Degenhardt states that, although the side effects of oral cannabis therapy appear to be minor in the short term, their longer-term effects, particularly in the setting of chronic illness, have yet to be studied.

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is the leading health sciences journal in Canada. CMAJ is a general medical journal publishing original research and review articles, commentaries and editorials, practice updates, an arts and ideas section and health news. Published continuously since 1911, new issues are uploaded on every second Monday at 4:30 p.m. EST/EDT. contains the complete editorial contents of CMAJ, supplemented by a variety of interactive features and additional content.

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