Occurrence of non-ototoxic antibiotic (cephazolin) in the inner ear

Cephazolin, a non-ototoxic antibiotic, and kanamycin, an ototoxic antibiotic, were administered to the guinea pig systemically and their tissue concentration was measured. Not only kanamycin but also cephazolin did occur in the inner ear as well as in the kidney and other tissues. Therefore, it is most likely that the accumulation of an antibiotic inside the inner ear forms only a sine qua non for its ototoxicity. The mechanism of the ototoxicity should exist in the antibiotic-vulnerable cells (hair cells) themselves.