Zaltoprofen, a non-steroidal anti-inflammatory drug, inhibits bradykinin-induced pain responses without blocking bradykinin receptors.

Zaltoprofen, a preferential COX-2 inhibitor, exhibited a potent inhibitory action on the nociceptive responses induced by a retrograde infusion of bradykinin into the right common carotid artery in rats. However, other COX-2 preferential inhibitors such as meloxicam and etodolac did not exhibit any apparent action, and also, preferential COX-1 inhibitors mofezolac and indomethacin, COX-1 and COX-2 inhibitor loxoprofen sodium showed a weak effect. These non-steroidal anti-inflammatory drugs (NSAIDs) except for zaltoprofen, strongly inhibited an acetic acid-induced writhing response related to PGs based on COX-1, at lower doses.