Auditory function after a prolonged course of ciprofloxacin-dexamethasone otic suspension in a murine model.

Objective: To test for ototoxicity after prolonged ototopical fluoroquinolone use in the middle ear space using a murine model.

Design: Nonrandomized controlled trial.

Subjects: Twelve CBA/J mice.

Interventions: The mice received daily intratympanic injections of ciprofloxacin-dexamethasone otic suspension for 21 days. The contralateral ear received daily intratympanic injections of sterile isotonic sodium chloride solution (saline) as a control.

Main Outcome Measures: Click-evoked auditory brainstem response (ABR) thresholds were obtained before injection and 10 days and 3 months after injection.

Results: Mean (SEM) preinjection ABR thresholds were 47.17 (2.74) dB peak equivalent sound pressure level (peSPL) in ciprofloxacin-dexamethasone-treated ears and 45.08 (1.56) dB peSPL in saline-treated ears (P = .38). Mean (SEM) postinjection ABR thresholds in ciprofloxacin-dexamethasone-treated ears were 44.25 (1.25) dB peSPL after 10 days and 43.00 (1.51) dB peSPL after 3 months. Mean (SEM) postinjection ABR thresholds in saline-treated ears were 48.00 (1.51) dB peSPL after 10 days and 45.92 (1.79) dB peSPL after 3 months. There were no significant differences in ABR thresholds for ciprofloxacin-dexamethasone-treated ears (P = .29, P = .10) or saline-treated ears (P = .07, P = .59).

Conclusion: Ciprofloxacin-dexamethasone suspension did not cause either immediate or delayed ototoxicity after 21 days of intratympanic administration in the CBA/J mouse model.