Pain Study Shows Mixed Results from Cannabis

Medium dose reduces capsaicin-induced pain, but higher doses have the opposite effect

MONDAY, May 8 (HealthDay News) -- A medium dose of cannabis may decrease pain but higher doses may increase it, according to research presented this week at the annual meeting of the American Pain Society in San Antonio, Texas.

Mark S. Wallace, M.D., of the University of California San Diego, and colleagues studied 15 healthy volunteers (four women, 11 men). During four sessions, the subjects were exposed to a low, medium or high dose of cannabis or a placebo, after which their forearms were injected with capsaicin.

Five minutes after any dose of cannabis exposure, the researchers found no effect on capsaicin-induced pain. Forty-five minutes after cannabis exposure, they found a significant decrease in capsaicin-induced pain in subjects given the medium dose, a significant increase in pain among subjects given the high dose and no effect with the low dose.

"This study suggests that there is a therapeutic window of analgesia for smoked cannabis with lower doses decreasing pain and higher doses increasing pain," the authors conclude. "Further studies are required to determine this therapeutic window and time course of analgesia."


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