Testicular toxicity of N-methyltetrazolethiol cephalosporin analogs in the juvenile rat

The testicular toxicity of 10 antibiotics was evaluated in juvenile rats. Three of the antibiotics, cefbuperazone, cefamandole, and cefoperazone, contain the N-methyltetrazolethiol group as the 3-substituent; ampicillin, cefazolin, cefotaxime, cephalothin, cefoxitin, piperacillin, and ceforanide do not contain this moiety. Testicular degeneration, partially irreversible in nature, was observed with those antibiotics which contain the N-methyltetrazolethiol substituent. Further, free N-methyltetrazolethiol also produced testicular degeneration in the juvenile rat. This substituent is most likely responsible for the testicular toxicity observed with cefbuperazone, cefamandole, and cefoperazone in the juvenile rat. The implications of these findings to man are undetermined.