Central inhibitory effect of intravenous ketoprofen on the nociceptive flexion reflex in man

In a double-blind, cross-over study, the nociceptive flexion reflex threshold of the biceps femoris was investigated in 10 healthy volunteers before and after intravenous administration of ketoprofen (100 mg in 5 ml) or placebo (5 ml). A significant difference was observed between the increase of reflex threshold produced by ketoprofen (+ 68%) and that produced by the placebo (+ 17%). These results show that ketoprofen has intrinsic inhibitory properties of the nociceptive flexion reflex, which could be explained by a central depressive effect on the transmission of nociceptive messages.