Salicylate antagonizes the antiinflammatory action of aspirin in the rat

On the ground of conflicting evidence concerning the interaction of salicylate and aspirin, we investigated the results of such interaction on carrageenin edema of the rat hint paw. Aspirin and sodium salicylate were administered by tube either singly or in combination, at a dose of 50 mg/kg each.Theantiinflammatory effectwas significantly greater when aspirin was administered prior to salicylate than when aspirin followed salicylate. It is therefore suggested that salicylate may antagonize the action of aspirin in vivo, and that the temporal order in which the two drugs interact; with cyclooxygenase may be an important determinant of the outcome.