Potentiating effects of cisplatin and ethacrynic acid in ototoxicity.

Seven milligrams per kilogram of body weight of cisplatin and 50 mg/kg of body weight of ethacrynic acid were given intravenously to guinea pigs. The threshold for Preyer's reflex, the cochlear microphonics (CM), and the endocochlear dc potential (EP) were measured during a four-day period after the injection. The changes in Preyer's reflex audiometry and the CM were more severe than that of the EP. These changes are greater than those that occur with the administration of each agent independently. The ototoxic interaction seemingly has a greater effect on the hair cells than on the stria vascularis. Baseline and periodic audiometry should be performed when both of these drugs are administered clinically.