The Clinical and Experimental Ototoxicity of Aminoglycosides.

Abstract

A prospective investigation of the incidence of ototoxicity is 35 patients treated with gentamicin is reported. Auditory function was assessed by serial pure-tone audiometry and vestibular function by simple clinical tests. Studies on 24 normal subjects showed that portable audiometry on the ward was reliable. However, 3 of the 25 patients in the control group, none of whom received a known ototoxic drug, had hearing losses. This has important implications for the design and interpretation of this and similar studies. The reliability of the monothermal binaural hot caloric test as a screening procedure for detecting aminoglycoside vestibulotoxicity was assessed using normal subjects. Sustained reductions in response occurred in some subjects indicating that this test would be unsuitable. Variation in binding of gentamicin to serum proteins is considered as a possible contributory factor to its toxicity. Irrespective of the method of study used, the binding of gentamicin to human serum proteins was found to be low and unlikely to be of clinical importance. Ribostamycin has been reported to be one of the least toxic aminoglycosides. The pharmacokinetics of this drug: in the serum and perilymph of guinea-pigs were examined in relationship to its toxicity. Results on the effects of different fixatives on the ultrastructure of the organ of Corti are also reported.