Efficacy of topotecan treatment on an experimental model of transient evoked otoacoustic emissions

Objective: The aim of this study was to investigate the effects of topoteca n (Hycamtin(R)), a topoisomerase I inhibiting anticancer agent, on Transien t Evoked Otoacoustic Emissions (TEOAEs) of the rabbits. We planned to inves tigate whether this test might provide a method for monitoring early ototox ic influence of drug administration to the cochlea. Methods: The study was conveyed in two groups each consisting of five rabbits with a total of ten ears. Rabbits in group I received i.v. topotecan (0.5 mg/kg once daily) for 3 days. Rabbits in group II received i.v. topotecan (0.25 mg/kg once daily ) for 3 days. Cochlear function was serially monitored using transient evok ed otoacoustic emissions before administration (BA) and on the 4th and 15th days after administration of topotecan. TEOAEs were analysed in terms of m ean stimulus, stability and emission amplitude at 1.0-4.0 kHz. Results: For group I and II, intergroup and intragroup, differences were not statistica lly significant in the mean stimulus, stability and emission amplitudes at 1.0-4.0 kHz. Conclusions: We evaluated the potential role of TEOAEs in earl y identification of cochlear dysfunction induced by, topotecan. It was conc luded that topotecan did not have ototoxic effects on the cochlea in the ea rly period of administration. TEOAEs may be useful: to monitor the cochlear function and to detect the late stage of ototoxicity especially in the pre sence of potentially toxic factors for the prevention of permanent damage. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.