Effect of riluzole on acute pain and hyperalgesia in humans.

Riluzole modulates several transmitter systems which may be involved in nociception. Antinociceptive effects have been shown in animal studies, but there are no human data. Therefore, we have examined the acute analgesic effect of riluzole in a human model of inflammatory pain induced by a thermal injury on the distal leg (47 degrees C, 7 min, 12.5 cm2) in 20 healthy volunteers. Hyperalgesia to mechanical and heat stimuli were examined by von Frey hairs and thermodes. We used a randomized, double-blind, placebo-controlled design, and subjects received riluzole 100 mg or placebo for 2 days with a 14-day interval. The burns produced significant hyperalgesia, but riluzole had no acute analgesic effects in normal or hyperalgesic skin.