Potency of several non-steroidal antiinflammatory drugs on airways responses to histamine

The effects of four non-steroidal antiinflammatory drugs (NSAIDs, indomethacin, flufenamate, aspirin and phenylbutazone) were investigated in anesthetized guinea-pigs. Bronchoconstriction (increased airways resistance and decreased conductance and compliance) was obtained to histamine (1-3 micrograms/kg i.v.). Each of the NSAIDs (0.1-20 mg/kg i.v.) enhanced bronchoconstriction to histamine. Maximum effects were obtained 12-44 min after administration of the NSAID. The order of potency of the drugs in causing a 50% increase in resistance responses to histamine was indomethacin greater than flufenamate greater than aspirin greater than phenylbutazone.