The effects of tocainide on audiological and electrophysiological responses in humans

This study reports on the systematic audiological evaluation of 18 cardiac patients receiving tocainide, an orally administered cardiac antiarrhythmic agent. The results of an audiological site of lesion test battery were compared with auditory brain stem response (ABR) measures. Of 35 ears tested, 17 (48%) presented ABR findings consistent with retrocochlear pathology. Audiological signs of retrocochlear pathology occurred less frequently and often in patients in whom ABR results suggested normal hearing or cochlear hearing loss. These data demonstrate that an extraneous agent, in this case tocainide, can affect ABR transmission times and that it is important to recognize such possible effects in order to interpret ABR data appropriately.