Pubdate: Tue, 17 Jun 2008
Source: Calgary Herald (CN AB)
Copyright: 2008 Canwest Publishing Inc.
Author: Pamela Fayerman, Canwest News Service
Referenced: The CMAJ article
Bookmark: (Marijuana - Medicinal)
Bookmark: (Marijuana - Medicinal - Canada)


The use of medical marijuana to relieve pain and other disease
symptoms can cause a huge range of adverse effects, say researchers
with the University of B.C. and McGill University.

Researchers analyzed 31 studies from around the world conducted over
the past 40 years and found that while nearly 97 per cent of adverse
events were not serious or life-threatening, medicinal marijuana users
still have an 86-per-cent increase in the rate of non-serious adverse
effects, such as drowsiness and dizziness, compared to non-users.

The study published in today's Canadian Medical Association Journal
found the risk of suffering serious, adverse effects requiring
hospitalization is not elevated in medicinal marijuana users, compared
to non-users.

However, studies on patients taking marijuana have shown that rarely,
serious effects have been documented, including multiple sclerosis
relapses, convulsions, respiratory and gastrointestinal disorders,
urinary infections, cancer tumour progression and psychiatric disorders.

Research on recreational marijuana users shows they have an increased
risk for psychosis and cancer, but the authors say no one should
assume that the same effects would apply to those using it for
medicinal purposes, due to different delivery systems and doses.

Dr. Jean-Paul Collet, one of the study authors who is a UBC professor
and pediatrician leading clinical research at B.C. Children's
Hospital, said in an interview that because of the small numbers of
cases and patients, it's impossible to say whether the serious effects
were directly related to the cannabis products.

"There is statistical validity to the non-serious effects like
nervousness, paranoia, hallucinations, dizziness and anxiety. But it
would be incorrect to talk about cannabis medicines causing an excess
risk of death at this point. We cannot make any conclusions about any
of the serious events. We need more information and more research in
order to see whether there are any trends," said Collet, who worked at
McGill University when the study was undertaken.

Since all the studies analyzed were short term (median of two weeks)
the effects of long term use are poorly understood and high-quality
trials are desperately needed.

"The use of these products is going up exponentially and doctors who
prescribe them want and need to know if they are safe or whether they
may create more problems," he said, adding "Health Canada is very much
in favour of research documenting risks and benefits."

As of a few months ago, 2,432 people in Canada were legally registered
as medicinal marijuana users. It's used to ease chemotherapy induced
nausea and vomiting, HIV-associated anorexia, and pain from multiple
sclerosis, arthritis or cancer. 
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