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Medical cannabis use a matter for patients, not trials

The use of cannabis for medical purposes should be decided by an informed discussion between doctor and patient, rather than relying on results of upcoming clinical trials in New South Wales, says the author of a Perspective published in the Medical Journal of Australia.

Professor David Penington, from the University of Melbourne, said the upcoming clinical trials had “confused” the debate about the medical use of cannabis in Australia.

“The clinical trial proposed, if successful, presumes that cannabis would then be approved and regulated as a pharmaceutical substance”, Professor Penington wrote.

“Cannabis can never be a pharmaceutical agent in the usual sense for medical prescription, as it contains a variety of components of variable potency and actions, depending on its origin, preparation and route of administration.

“Consequently, cannabis has variable effects in individuals. It will not be possible to determine universally safe dosage of cannabis for individuals based on a clinical trial.”

Professor Penington said the debate in Australia had been characterised by extreme views on both sides, both in conflict with existing evidence about cannabis’ harms and benefits.

Australia is behind the times, he maintained, as 23 states in the United States, Canada, Israel, Holland and the Czech Republic, all permit its use in medical situations.

“Eliminating prohibition is not a disaster if there are sensible processes to control drug-related harms”, he wrote.

“There is no rational basis for the view that weakening prohibition to permit use for medical conditions would lead to a surge in general use.”

“A recent US study found that the states with medical cannabis use over 10 years had a lower death rate from opioid overdose than those without”, Professor Penington noted.

Medical uses of cannabis include relief from pain in the last stages of cancer, muscle spasms in multiple sclerosis and nausea caused by chemotherapy, and reducing seizures in rare conditions such as Dravet syndrome.

“If legislation permits sale to people suffering from a condition diagnosed by a doctor and scheduled in legislation, there should be no problem with provision of cannabis by this route without waiting for completion of a clinical trial”, Professor Penington concluded.

“Use of cannabis should be decided by the patient, following medical advice about the condition from which they seek relief, with patients being registered under state legislation.”


Medical cannabis: time for clear thinking, David G Penington DM, FRCP, FRACP, Medical Journal of Australia, doi: 10.5694/mja14.01573, published 2 February 2015.

Source: Australian Medical Association (AMA)