Abstract
There have been reports of sudden hearing loss under treatment for erectile dysfunction with phosphodiesterase type-5 inhibitors. This study investigated the possible damaging effect on the cochleae in rats using the otoacoustic emission method.
Wistar albino rats were divided into four groups. Each group received Sildenafil, Vardenafil, Tadalafil, or saline orally for 28 days. Distortion product otoacoustic emission measurements were conducted at the beginning of the study and on the 14th and 28th days (stimulation 65/55 decibels). Paraffin block serial sections of the mid-modiolar area (up to 5 µm thick) were prepared, stained with hematoxylin and eosin, and evaluated using light microscopy.
A statistically significant decrease in the distortion product was observed in group 1 (sildenafil) on day 28 at stimulus intensities of 65/55 dB (p < 0.05). Conversely, a statistically significant increase was detected in group 3 (tadalafil). No statistically significant change was noted in group 2 (vardenafil). When comparing the three groups, we found no statistically significant difference in the number of outer ciliated cells. Differences in stria vascularis and spiral ganglion were statistically insignificant among the three groups (p>0.05).
Sildenafil has an ototoxic effect on cochleae. This effect was not observed in the tadalafil and vardenafil groups. This study also revealed that the ototoxic side effect of sildenafil was dependent on exposure time.