Comparative study of the interaction between sulfamethizole and ibufenac, sulindac or mepirizole at the renal level in rats.

The effects of three non-steroidal anti-inflammatory drugs, ibufenac, sulindac and mepirizole, on the renal excretion of sulfamethizole in rats were investigated, in order to clarify the mechanisms involved. The clearance ratio of sulfamethizole was markedly decreased after infusion of ibufenac, while sulindac or mepirizole had no effect on the clearance ratio of sulfamethizole. From this result, it is speculated that the decrease of renal excretion of sulfamethizole caused by ibufenac is mainly due to competitive interaction between sulfamethizole and ibufenac at the renal secretory level. The correlation between the chemical structures of some anionic non-steroidal anti-inflammatory drugs and the characteristics of renal tubular transport is discussed.