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.


METHODS
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.


CONCLUSIONS
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.
Iwanaga
Tetsu
T
Division of Otorhinolaryngology, Department of Translational Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, Japan.
Tanaka
Fujinobu
F
Tsukasaki
Naoki
N
Terakado
Mariko
M
Kaieda
Satoru
S
Takasaki
Kenji
K
Kumagami
Hidetaka
H
Takahashi
Haruo
H
D000287:Administration, Topical; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage* / Q000633:toxicity*; D007758:Ear, Inner / Q000187:drug effects* / Q000502:physiology; D004594:Electrophysiology; D005072:Evoked Potentials, Auditory; D005472:Fluorouracil / Q000008:administration & dosage* / Q000633:toxicity*; D006168:Guinea Pigs; D006198:Hair Cells, Auditory / Q000187:drug effects; D008297:Male; D008855:Microscopy, Electron, Scanning; D009824:Ointments; D013316:Stria Vascularis / Q000187:drug effects
D000964:Antimetabolites, Antineoplastic; D009824:Ointments; D005472:Fluorouracil