Ototoxicity of triethanolamine polypeptide (cerumenex) in the chinchilla.
The use of earwax softeners and cerumenolytics to unblock the external auditory canal is increasing. Although reports on their effectiveness are available, data about their effect on hearing are limited.


OBJECTIVE
To assess the effect of ototopic triethanolamine polypeptide oleate condensate 10% (Cerumenex) on hearing.


METHODS
Prospective, randomized, controlled trial in a chinchilla animal model.


METHODS
Tympanostomy tubes were inserted in five chinchillas, and hearing was assessed with distortion product otoacoustic emissions (DPOAE) between 1 and 9 kHz prior to application and at days 1, 4, 30, and 100 postototopic application of Cerumenex. One ear received Cerumenex; the other ear served as control. Postmortem scanning electron microscopy was performed to assess the cochlear hair cells.


RESULTS
A reduction in the mean DPOAE signal was shown in the ears treated with Cerumenex from the first day after treatment and throughout the study. Almost all tested frequencies were affected. Swelling, crusting, and fluid were observed in four of the five experimental ears. One animal also developed facial paralysis in the experimental side. Electron microscopy showed damage of the outer and inner hair cells in the Cerumenex-treated ears.


CONCLUSIONS
In the chinchilla, when a tympanic perforation is present, Cerumenex causes a reduction in DPOAE signal and damage to the cochlear hair cells. Caution should be observed when prescribing this agent if the status of the tympanic membrane is unknown. Furthermore, its use without medical prescription should be discouraged because of the risk of ototoxicity and severe inflammatory reaction.
Daniel
Sam Joseph
SJ
McGill University, Montreal, Quebec, Canada. sam.daniel@mcgill.ca
Sahmkow
Sofia Isabel
SI
Munguia
Raymundo
R
Schloss
Melvin
M
Akache
Fadi
F
D000818:Animals; D002682:Chinchilla; D002724:Chlorobutanol / Q000009:adverse effects*; D004338:Drug Combinations; D004427:Ear Diseases / Q000139:chemically induced*; D004983:Ethanolamines / Q000009:adverse effects*; D005260:Female; D010455:Peptides / Q000009:adverse effects*
D004338:Drug Combinations; D004983:Ethanolamines; D010455:Peptides; C033026:trolamine polypeptide oleate-condensate; D002724:Chlorobutanol