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National Institute of Dental Research
Fact Sheet on the Use of
Marijuana for Chronic Pain
Many of the compounds contained in marijuana have been
found to have pain-relieving actions in animal tests, as pointed out in the current
edition of Goodman and Gilman's The Pharmacological Basis of Therapeutics, one of the
foremost medical reference tests. There have been limited studies of cannabinoid effects
on pain in patients. There were single-dose studies, which showed that the cannabinoid had
some pain-relieving effects, but produced sedation and mood alterations in many of the
patients. These symptoms were disturbing to patients who were not experienced marijuana
users, but did not apparently trouble those who customarily used the drug. Occasionally,
patients with chronic pain that did not respond to any conventional treatments have
reported that they get some useful relief by smoking marijuana. No controlled studies of
the effect of marijuana itself on acute or chronic pain exist.
Marinol, a synthetic form of marijuana's active
ingredient, THC (delta-9-tetrahydrocannabinol, trade name Dronabinol), is currently
available from Roxane Laboratories, Inc. The approved indications are for the treatment of
nausea and vomiting associated with cancer chemotherapy and for anorexia associated with
HIV wasting syndrome.
Other Problems Associated with Inhalation of Marijuana
Are:
1. Drug absorption is dependent on deep inhalation of
marijuana smoke and may be impractical or unacceptable for non-smoking patients.
2. Marijuana cigarette smoke contains a complex mixture of
over 400 compounds including polyaeromatic hydrocarbons which are carcinogenic. This would
be a concern for anyone, but specifically for patients with chronic disorders and/or
impaired immune systems.
3. Biologic contamination of marijuana with salmonella and
fungal spores has been reported. This again poses a concern for patients with chronic
conditions and/or compromised immune systems.
There is insufficient evidence to recommend
marijuana as the treatment of choice for any patient with any pain condition. For most
patients, marijuana will have problematic side effects. There may well be some patients
for whom marijuana is a moderately effective pain reliever when no other treatment is of
benefit, but this has not been rigorously studied.
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