MEDICAL MARIJUANA SHOWS PROMISE FOR PAIN

But Scientists and Doctors Are Divided on the Medicinal Benefits Of
Smoking the Drug

After all the usual and proper medical approaches did nothing for her
pain, Cheryl Campbell, a nurse and mother, says she finally built up
the courage to ask her doctor, "How do you feel about prescribing me
marijuana?"

The 30-year-old Ottawa woman suffers from fibromyalgia and chronic
fatigue syndrome. Her pain is body-wide - a constant, sometimes
stabbing ache in her back, hips, knees, shoulders and virtually every
joint. Doctors once put her on morphine. It cut the pain, but she
couldn't function. She says her mind felt so heavy with fog she
couldn't carry on a conversation.

She's been using marijuana for pain for two years; she has a federal
licence to possess it. She says it helps her sleep at night. In the
morning, it helps ease the stiffness in her hips and back enough that
she can make it into the shower.

Campbell says she owes her ability to get through each day to a drug
that critics condemn, especially when it's smoked - which is how most
of the thou-sands of Canadians who self-medicate with pot prefer to
take it. The U.S. Drug Enforcement Agency was unequivocal earlier this
year: Smoked marijuana is not medicine, and it's not safe.

"No matter what medical condition has been studied," the agency ruled,
"other drugs already approved by the [U.S. Food and Drug
Administration] have been proven to be safer than smoked marijuana."

But research into medicinal marijuana is undergoing a surge of
interest, with more evidence emerging not only of its ability to ease
human suffering, but also of its apparent safety.

Some say cannabis may be less toxic to humans than over-the-counter
pain relievers.

Four small but scientifically controlled experiments in recent years
have concluded that smoked cannabis can provide moderate relief from
chronic, severe non-cancer pain - including HIV-related nerve pain and
post-traumatic neuropathy, a dreaded condition that can follow an
injury or medical procedure. Both are notoriously resistant to
conventional treatments.

Scientists are only beginning to tease out the possible anti-cancer
properties of pot. Early experiments in animals suggest that purified
forms of THC and cannabidiol - two major constituents of marijuana -
can induce certain cancer cells, including breast cancer cells, to
essentially kill themselves off - a process known as apoptosis. The
cells self-destruct; they stop dividing and spreading. Cannabinoids
also seem to shut down a tumour's life-giving blood supply.

Meanwhile, researchers across Canada are testing cannabinoids against
arthritis, glaucoma and gastrointestinal inflammatory diseases, such
as Crohn's.

"Science is just scratching the surface," says Dr. Mark Ware, head of
the Canadian Consortium for the Investigation of Cannabinoids and
director of clinical research at the Alan Edwards Pain Management Unit
at Montreal's McGill University Health Centre.

In Canada, synthetic versions of THC and other pure cannabinoids are
already available by prescription - pills and sprays approved for
cancer pain, for nausea associated with chemo-therapy, to stimulate
appetite and for the relief of the pain and spasticity of multiple
sclerosis.

Medical marijuana, Ware argues, is essentially just a different
delivery system for cannabinoids.

It's crude, he acknowledges. It's also associated with potential harms
through the sheer act of burning the plant and smoking it. But even
then, he says the evidence is uncertain. "It's not a done deal that
smoking cannabis alone is as potent a cancer-causing agent as
tobacco," Ware says.

According to U.S. drug enforcement officials, while smoked marijuana
can cause changes in lung tissue that may very well unleash cancer,
"it's not possible to directly link pot use to lung cancer based on
existing evidence."

But does it have any legitimate role in medicine?

Modern interest in cannabis exploded in the 1980s when researchers
discovered all mammals - notably humans - have an endogenous, or
built-in, cannabinoid system.

Essentially, we make our own marijuana.

Two types of receptors for cannabinoids - CB1 and CB2 - are found in
the brain and spinal cord, nerve cells and immune tissues. The body
produces a natural, THC-like chemical called anandamide - the
so-called "bliss chemical" - that binds to these receptors. Anandamide
has been found to play a part in pain, anxiety and depression.

The reason we don't walk around high all the time is that anandamide
is released only in response to noxious or painful stimuli, such as an
injury or inflammation. The neurotransmitter latches onto the
receptors and, in the case of pain, helps settle down the firing of
nerves in the pain pathway. But it's bro-ken down quickly, chewed up
by enzymes so rapidly it never reaches a level sufficient enough to
cause a high.

Despite its widespread illegal use, there are few, "if any," reports
of fatal overdoses from cannabis, said Les Iversen chair of the U.K.
government's Advisory Council on the Misuse of Drugs and author of The
Science of Marijuana. By contrast, thousands die each year from
"catastrophic" bleeding in the gut caused by non-steroidal
anti-inflammatory drugs, or NSAIDS, he said.

The most common side-effects are sedation and foggy thinking. "You can
also get high," says Dr. Mary Lynch, director of the pain management
unit at Queen Elizabeth II Health Sciences Centre in Halifax. "But
many of our patients adjust the dose so they can avoid the
side-effects and aim for the therapeutic effects, similar to the way
we use any drug."

Dr. Meldon Kahan and others worry that smoked marijuana's promotion
among users as a legitimate medicine, especially for pain, is driving
a rise in illicit use at a time when Canadians are already among the
highest per capita users of pot in the western world.

"A lot of people - particularly young people - are harmed by the
notion that cannabis is this harmless herb," says Kahan, a physician
and associate professor in the department of family medicine at the
University of Toronto.

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PROS AND CONS OF MEDICAL MARIJUANA

Pros:

. May offer pain relief to people suffering from chronic neuropathic
pain - pain caused by accidental or surgical injury to nerves

. Effective for HIV-related pain and an appetite stimulant for people
living with AIDS

. May provide relief for painful muscle spasms due to multiple
sclerosis

. May reduce opioid dose in treatment of chronic, non-cancer
pain

. Cannabis smoking by itself does not appear to be a major risk factor
for head, neck or lung cancer

. Can improve mood and sleep in patients with chronic
pain

Cons:

. Can cause drowsiness, dry mouth, headache; can impair psychomotor
skills

. Increased risk of heart attack within one hour of
use

. May trigger psychosis in those who are vulnerable due to personal or
family history

. Can cause changes in lung tissue with long-term use that may lead to
cancer

. Possible increased risk of cardiovascular disease

. Little known about long-term safety concerns

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