Pubdate: Wed, 08 Jul 2015
Source: Guardian, The (CN PI)
Copyright: 2015 The Guardian, Charlottetown Guardian Group Incorporated
Contact:  http://www.theguardian.pe.ca/
Details: http://www.mapinc.org/media/174
Author: Desmond Colohan
Note: Desmond Colohan, MD, recently retired from the clinical 
practice of pain medicine.
Page: A7

MUCH TO LEARN ABOUT MEDICAL MARIJUANA

A recent front-page headline in the Guardian was sure to get the 
attention of the many Islanders suffering from acute and chronic pain.

It reported on a conference on medical marijuana held in 
Charlottetown. The keynote speaker delivered a sincere endorsement of 
cannabis in helping him manage his chronic back pain and symptoms of 
multiple sclerosis. He recommended that physicians use cannabis as a 
first line drug to treat pain.

He implied that many physicians are ignorant of the benefits of 
cannabis and need to be encouraged to "get with the program."

As a specialist in pain medicine, I have had considerable experience 
working with patients using medical marijuana, and, with due respect, 
would caution that marijuana is not "safer than water," nor is it as 
essential to life.

Physicians are hesitant to embrace not yet proven therapies, 
particularly when the preponderance of support comes from 
testimonials and political activism, and not through carefully 
designed clinical testing.

Opinions to the contrary, we do indeed know quite a bit about 
cannabis, its botany, its effects on humans, its clinical utility and 
many of its risks and benefits.

Unfortunately, much of our knowledge comes from animal research and 
not a whole lot from clinical testing on humans.

According to our experts, here's some of what we know.

Clinical studies supporting the safety and efficacy of smoked 
cannabis for therapeutic purposes are limited, but slowly increasing 
in number. There are no clinical studies on the use of cannabis 
edibles (e.g. cookies, baked goods) or topicals for therapeutic 
purposes. It has been repeatedly observed that the psychotropic side 
effects of cannabinoids limit their utility.

Cannabis smoke contains many compounds not found in either extracts 
or vapour, including a number which are known or suspected 
carcinogens or mutagens. Moreover, comparisons between cannabis smoke 
and tobacco smoke have shown that the former contains many of the 
same carcinogenic chemicals found in tobacco smoke.

The body's endocannabinoid system plays an important role in the 
modulation of pain states. Research involving patients suffering from 
pain suggests that cannabinoids may be most effective for chronic, 
primarily neuropathic pain.

There is evidence that cannabis dependence (physical and 
psychological) occurs, especially with chronic heavy use. The 
addiction potential for cannabis has been estimated at about nine per 
cent, compared to nicotine at 32 per cent or heroin at 23 per cent.

Cannabis should not be used by any person under the age of 18. The 
adverse effects of cannabis on mental health are greater during 
adolescence than in adulthood. The risk of an acute psychotic break 
by age 26 is 4.5 times higher in regular cannabis smokers who start 
at age 15. It is 1.6 times higher if cannabis smoking doesn't start 
until age 18. The risk of developing schizophrenia doubles in regular 
cannabis users, particularly those using high-potency sinsemilla 
[skunk] who start in their early teens. Chronic cannabis use may have 
negative effects on memory.

The routine use of cannabinoids to treat primary anxiety or 
depression should be viewed with caution, and especially discouraged 
in patients with a history of psychotic disorders.

Cannabis should be used cautiously in patients with a history of 
substance abuse because such individuals may be more prone to abusing cannabis.

Cannabis should be used with caution in patients receiving 
concomitant therapy with sedative-hypnotics or other psychoactive 
drugs because of the increased risk of overdose or addiction due to 
additive or synergistic CNS depressant or psychoactive effects.

Cannabis is not recommended for women of childbearing age not on a 
reliable contraceptive, as well as those planning pregnancy, who are 
pregnant or women who are breastfeeding. Men, especially those on the 
borderline of infertility and intending to start a family, are 
cautioned against using cannabis since exposure could potentially 
reduce the success rates of intended pregnancies.

Patients using cannabis should be warned not to drive or to perform 
hazardous tasks because impairment of mental alertness and physical 
coordination may decrease their ability to perform such tasks.

The estimated human lethal dose of intravenous tetrahydrocannabinol 
[THC] is 30 mg/kg, although there have been no documented deaths 
exclusively attributable to cannabis overdose.

In my experience, the therapeutic value of cannabis in managing 
chronic pain is limited by its adverse effects.

We still have a lot to learn about the appropriate clinical use of ' 
medical marijuana' and should not be in a hurry to jump on this bandwagon.
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MAP posted-by: Jay Bergstrom