Antagonism by meseclazone and other nonsteroidal anti-inflammatory drugs of bradykinin-induced bronchospasm

Bradykinin-induced bronchoconstriction is due, in part, to release of TXA2 and prostaglandins. Intravenous administration of meseclazone and other nonsteroidal anti-inflammatory drugs caused a dose-dependent inhibition of bronchoconstriction resulting in the following order of descending potency: isoproterenol congruent to indomethacin greater than fenoprofen greater than tolmetin greater than aspirin greater than naproxen congruent to ibuprofen greater than phenylbutazone greater than diflunisal greater than meseclazone greater than 5-CSA. This order of potency does not correlate with that obtained with these compounds for in vitro relaxation of tracheal smooth muscle, an effect which may be related to inhibition of prostaglandin synthesis.