Commercial Quinolone Ear Drops Cause Perforations in Intact Rat Tympanic Membranes.

ABSTRACT

HYPOTHESIS: Commercial quinolone ear drops may promote the development of perforations (TMPs) in intact tympanic membrane (TMs). BACKGROUND: Quinolone ear drops have been associated with TMPs after myringotomy +/- tube placement in a drug-specific manner and potentiation by steroids. METHODS: Rats were randomized to six groups (10/group), with one ear receiving otic instillation of dexamethasone, ofloxacin, ciprofloxacin, ofloxacin + dexamethasone, ciprofloxacin + dexamethasone, or neomycin + polymyxin + hydrocortisone-all commercial formulations and at standard clinical concentrations-and the contralateral ear receiving saline, twice daily for 10 days. TMs were assessed over 42 days. RESULTS: No TMPs were seen in ears treated with saline, dexamethasone, or neomycin. At day 10, TMPs were seen in one of 10 ofloxacin- and three of 10 ciprofloxacin + dexamethasone-treated ears (p = 0.038). At day 14, the ofloxacin TMP healed. In contrast, the three ciprofloxacin + dexamethasone TMPs remained and one new TMP developed in this group. A ciprofloxacin and an ofloxacin + dexamethasone-treated ears also had TMPs (p = 0.023). By day 21, the ofloxacin + dexamethasone TMP and two of four of the ciprofloxacin + dexamethasone TMPs healed but two new TMPs were seen in ciprofloxacin + dexamethasone ears (p = 0.0006). At day 28, 1 of 10 ciprofloxacin and 4 of 10 ciprofloxacin + dexamethasone-treated ears had TMPs (p = 0.0006). By day 35, only one ciprofloxacin + dexamethasone had TMP (p = 0.42). All TMPS were healed at day 42. CONCLUSIONS: Application of commercial quinolone ear drops can cause TMPs in intact TMs. This effect appears to be drug-specific and potentiated by steroids.