• Denise Murphy and Sam J Daniel.
• McGill Auditory Sciences Laboratory, McGill University, Montreal, Quebec, Canada.
• Otolaryngol Head Neck Surg. 2011 Sep 1; 145 (3): 452-7.

ObjectiveTo determine whether intratympanic administration of dexamethasone reduces ototoxicity from systemic cisplatin.Study DesignProspective animal study. Setting. Cisplatin chemotherapy induces ototoxicity manifesting as irreversible, sensorineural hearing loss. This is due to damage to the inner ear structures by free radicals. Steroidal anti-inflammatories have been shown to reduce the formation of free radicals and protect hearing in animal models.Subjects And MethodsPure tone auditory brainstem responses were obtained in 58 female albino guinea pigs before and 3 days after intraperitoneal (IP) cisplatin chemotherapy. Auditory brainstem responses were also taken up to 1 month after a low dose of cisplatin. Part I consisted of a dosing study to determine the optimal ototoxic dose of cisplatin. In part II, auditory brainstem response thresholds were compared after bilateral intratympanic dexamethasone doses to act as controls. For part III, the otoprotection of dexamethasone against cisplatin was tested in separate bilateral and unilateral studies.ResultsIP injection of 12 mg/kg of cisplatin induced significant hearing loss (57.2 ± 4.4 dB, P < .01) with 0% mortality. Ears treated with intratympanic dexamethasone alone showed no significant threshold changes. Ears that received IP cisplatin and intratympanic dexamethasone showed reduced threshold shifts at 8 kHz when the greatest concentration of dexamethasone was administered.ConclusionModest intratympanic dexamethasone otoprotection of the guinea pig ear was greatest at the highest concentration tested and occurred in a frequency-dependent manner. Intratympanic dexamethasone presents as a safe, simple, and effective treatment modality to minimize cisplatin ototoxicity without interfering with the chemotherapeutic effects of cisplatin.

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