Central effects of zomepirac on pain evoked by intraneural stimulation in man.

The central analgesic activity of zomepirac was studied in six healthy subjects by means of intraneural electrical stimulation. Pain elicited by selective activation of nociceptive fibers was inhibited by the administration of a single oral dose of 100 mg zomepirac. Pain relief in this double-blind crossover study was significantly greater after zomepirac than after placebo. Maximal analgesic effect was observed between 30 and 90 minutes after ingestion. Since peripheral receptors are bypassed by this technique, it is postulated that the observed effect reflects a central action of zomepirac, possibly as a result of inhibition of prostaglandin synthesis in the central nervous system.