Nephrotoxicity of Cephalothin-Aminoglycoside Interactions

To the Editor.  —The article by Wade et al published in the Archives (1981;141:1789-1793) provides further verification of the nephrotoxicity of the cephalothin sodium-aminoglycoside interaction. The authors were unable to reconcile the protective effect of cephalothin on toxic reactions to aminoglycosides in the animal model with the published results in clinical trials that disclose a notable nephrotoxic effect of the combination.A possible explanation for this disparity stems from an article by Bloch et al¹ that compared the protective effects of carbenicillin disodium and cephalothin on toxic reactions to aminoglycosides in Sprague-Dawley rats. They found that a substantial partial protection from toxic reactions occurred when doses of 500 mg/ kg of cephalothin sodium and 100 mg/ kg of carbenicillin disodium were used. Cephalothin imparted protection only at a dose far in excess of that used clinically, whereas carbenicillin was effective at a dose within range of that normally used