Right Dose of Pot Can Ease Pain

WEDNESDAY, Oct. 31 (HealthDay News) -- Smoking marijuana can help alleviate pain, but only when used at the right strength, a U.S. study finds.

A team at the University of California, San Diego, found that a low dose of pot produced no effect, a moderate dose provided moderate pain relief, and a high dose actually increased smokers' pain.

Researchers used capsaicin -- the "hot" component in chili peppers -- to induce skin pain in 15 healthy volunteers, who then smoked marijuana cigarettes with different levels of THC, the active ingredient in cannabis.

"Subjects reported a decrease in pain at the medium level (4 percent THC by weight), and there was also a significant correlation between plasma levels of THC ... and decreased pain," Dr. Igor Grant, professor and executive vice-chair of the department of psychiatry, and director of the university's Center for Medical Cannabis Research, said in a prepared statement.

"Interestingly, the analgesic effect wasn't immediate; it took about 45 minutes for the cannabis to have an impact on the pain," Grant said.

The findings, published in the November issue of the journal Anesthesiology, suggest that there's a "therapeutic window" for cannabis pain relief.

"This study helps to build a case that cannabis does have therapeutic value at a medium-dose level. It also suggests that higher doses aren't necessarily better in certain situations -- something also observed with other medications, such as antidepressants," Grant said.