Marijuana can ease pain even for longtime sufferers of disease, but the
illegal herb's mind-altering properties make it less than ideal as a

German researchers now have found that a synthetic version of one of many
marijuana compounds safely reduced chronic nerve pain without impairing
thinking and behavior. If the preliminary findings hold up in larger
trials, capsules containing this compound might one day be prescribed for
hard-to-treat pain.

The principal active ingredient in cannabis is tetrahydrocannabinol, or
THC. That compound has been the most studied, but researchers around the
world are also looking more closely at the plant's other chemical compounds
for potential health benefits. Scores of them belong to a group called
cannabinoids; others include flavonoids, which are thought to have
antioxidant properties.

"It's not a surprise that these cannabinoids have medical benefit," said
Dr. Donald I. Abrams, an AIDS specialist conducting clinical trials of
marijuana at San Francisco General Hospital.

People with cancer, AIDS and other chronic diseases have long attested to
the plant's ability to provide relief from nausea and pain. "That's why
we're investigating marijuana," Abrams said.

Previous studies have shown some cannabinoids have limited ability to blunt
acute nerve pain, typically associated with an injury. But the German study
found that a cannabinoid called CT-3 could help sufferers of chronic
neuropathy, who often don't respond to standard medications.

CT-3 is related to THC. But the problem with THC is that even at low doses,
it can impair thinking and coordination, and create anxiety, panic attacks,
psychosis and paranoia, as well as dry mouth, blurred vision, and a drop in
blood pressure upon standing.

Despite these effects, scientists have remained interested in cannabinoids,
because the body has natural cannabinoid receptors that offer potential
drug targets.

CT-3 first showed promise in animals as an anti-inflammatory and as a
reliever of two aspects of neuropathy: pain and extreme sensitivity to
ordinary sensations.

Researchers at Hannover Medical School in Germany, working with an American
colleague, gave various doses of CT-3 to 24 volunteer patients with chronic
neuropathic pain in places such as the foot, arm, face and head. Many
patients also were taking other pain-relieving medications such as
narcotics, muscle relaxants, antidepressants and sedatives.

The researchers found that CT-3 was more effective than a placebo at
relieving pain; its effects were greatest with milder pain. Increasing the
dose brought no greater relief. The major side effects were dry mouth and

"What's promising is that there can be a product that stimulates the
cannabinoid receptors and does not have the emotional and hallucinatory
effects otherwise known for THC," said Dr. Joel Saper, a neurologist who
directs the Michigan Head-Pain and Neurological Institute in Ann Arbor.
He'd like to see longer CT-3 studies using larger numbers of patients who
aren't taking other pain medications: "We need to see how this would work
in patients not on all these drugs."

Pubdate: Mon, 13 Oct 2003
Source: Los Angeles Times (CA)
Copyright: 2003 Los Angeles Times