Does Topical Application of 5-Fluorouracil Ointment Influence Inner Ear Function?

OBJECTIVE: To investigate the effect of 5-fluorouracil (5-FU) ointment on the inner ear of guinea pigs.

STUDY DESIGN AND SETTING: In group A (n = 7), 5-FU ointment was applied into the left external auditory canal. In group B (n = 10), 5-FU ointment was applied to the left middle ear through myringotomy. In both groups, the right ear served as a control. One week later the endocochlear DC potential (EP) was measured and morphology of the cochleae was examined using scanning electron microscopy (SEM) and light microscopy.

RESULTS: In group A, there was no significant difference between the EP values of the experimental side and the control side. In group B, there was a statistically significant difference between them (P < 0.05). Morphologic findings showed no damage.

CONCLUSION: 5-FU ointment application to the external ear seems to be safe but its application to the middle ear may pose some risk of ototoxicity.