The effect of loop diuretics on the vestibular system. Assessment by recording the vestibular evoked response

Whether or to what extent loop diuretics, e.g., ethacrynic acid and furosemide, affect the vestibular system is controversial. We studied this problem by recording in cats the short-latency vestibular evoked response (VsER) to acceleration stimuli by skin electrodes before and after local or systemic administration of loop diuretics. The effect on the VsER was minimal in contrast to the major changes that appeared in the auditory evoked response, in which, among the waves known to originate from the brain stem, the most affected was N1. These findings suggest that the vestibular end-organ function is minimally affected by loop diuretics and that the changes in the vestibulo-ocular reflex reported by several authors might be due to the effect of the drugs on the central nervous system. Thus, recording of the VsER in experimental animal models might serve as a useful tool for direct evaluation of the effect of certain drugs and conditions on the vestibular system.