Effects of modern loop diuretics on the inner ear a quantitative evaluation using computer technics

Furosemide ototoxicity: clinical and experimental aspects

Furosemide is an ototoxic diuretic. Furosemide injection is followed by a rapid, but reversible decrease of the endocochlear potential and eighth nerve action potential with a more gradual decrease of the endolymph potassium concentration. In contrast to the reversible effects of furosemide alone on the cochlea, the combination of kanamycin with furosemide resulted in irreversible changes in cochlear function which were associated with elevated levels of kanamycin in the blood and perilymph of the experimental animals. There was a striking similarity between the blood level measured by high pressure liquid chromatography at the time of recovery of auditory function in experimental animals and the ototoxic blood levels proposed by others in clinical literature. These findings help to provide a pharmacologic basis for the clinical observation of furosemide-induced hearing loss.

Are aminosugars ototoxic?

The ototoxicity of the kanamycin fragment 3-amino-3- deoxy-D-glucose (3-aminoglucose, kanosamine), was investigated by perilymphatic perfusion in the guinea pig. Concentrations of 10 or 28 mM of this compound had no effect on cochlear microphonic potentials (CM), contrasting with previous observations (Owada 1962). Kanamycin at 1 mM decreased CM significantly under otherwise identical conditions. The action of kanamycin was at least partially reversible.