Drs Kahan and Srivastava assert that marijuana is prescribed “under the guise of medical treatment” and objectto “disguising itas medical therapy.” This refusal to accept that some patients use cannabis as part of medical care runs contrary to current medical opinion, including the Canadian Medical Association’s position.1 Under the Marihuana Medical Access Regulations, cannabis is not prescribed.
Drs Kahan and Srivastava claim that cannabis use causes “pleasant psychoactive effects that are easily confused with direct analgesia.” Cannabinoids have complex central actions, including analgesia. Are pleasant side effects a valid reason to withhold the drug from chronically ill patients?
They list a number of risks, many of which are controversial. The carcinogenic potential of cannabis is not supported by clinical evidence. Exposure to smoked cannabis (50 joint-years; equivalent to 1 joint daily for 50 years) is not independently associated with increased risk of aerodigestive cancer; light cannabis use (<1 joint-year) might actually reduce risk of lung cancer.2 The anticancer properties of cannabinoids are fascinating.3 Cognitive effects of cannabis disappear after cessation of heavy use (50 joint-years).4 The risk for fatal accidents might actually be reduced compared with controls following cannabis use.5 No evidence of abuse of prescription cannabinoids has been found.6
Most cannabis research has been conducted under a paradigm of prohibition, and the study of risks is not yet balanced by much-needed research on benefits. All drugs have risks. To reject the therapeutic potential of cannabis and cannabinoids on the grounds of toxicity and potential abuse is to throw the baby out with the bath water.
Footnotes
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These rebuttals are responses from the authors who were asked to discuss “Is there a role for marijuana in medical practice?” in the Debates section of the December issue (Can Fam Physician 2006;52:1531-3 [Eng], 1535-7 [Fr]). In these rebuttals, the authors refute their opponents’ arguments.
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