Inhaled Cannabis Has Biphasic Effect On Capsaicin-Induced Pain, Study Says

La Jolla, CA: Inhaling cannabis is associated with both an increase and a decrease in humans’ response to painful stimuli, according to clinical trial data to be published in the forthcoming issue of the journal Anesthesiology.

Investigators at the University of California at San Diego (UCSD) assessed the effects of smoked marijuana on capsaicin-induced pain in 15 healthy volunteers. (Capsaicin is the active component of chili peppers.) Participants in the trial inhaled cigarettes containing either cannabis of varying strengths or a placebo.

Subjects who inhaled medium-potency cannabis (4 percent THC) reported that they experienced a significant reduction in capsaicin-induced pain 45 minutes after smoking. By contrast, subjects provided high-potency pot (8 percent THC) reported experiencing an increase in pain.

Participants reported that inhaling low-potency cannabis (2 percent THC) did not affect their pain response.

“Our study suggests that there is a therapeutic window for analgesia, with low doses being ineffective, medium doses resulting in pain relief, and high doses increasing pain,” lead investigator Mark Wallace said in a UCSD press release.

A previous clinical trial conducted earlier this year found that smoking medium-potency cannabis (3.56 THC) significantly reduced HIV-associated neuropathy (nerve pain).

For more information, please contact Paul Armentano, NORML Senior Policy Analyst, at: paul@norml.org. Full text of the study, “Dose-dependent effects of smoked cannabis on capsaicin-induced pain and hyperalgesia in healthy volunteers,” will appear in Anesthesiology.