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April 1992

Ciprofloxacin: Use as a Topical Otic Preparation

Author Affiliations

From the Division of Otolaryngology—Head and Neck Surgery, University of North Carolina Hospitals, Chapel Hill. Dr Brownlee is now in a fellowship with the Department of Otolaryngology Head and Neck Surgery, University of Oregon Health Sciences Center, Portland.

Arch Otolaryngol Head Neck Surg. 1992;118(4):392-396. doi:10.1001/archotol.1992.01880040050009

• Most common topical otic preparations have been shown to cause sensorineural hearing loss and hair-cell damage in experimental animals. Ciprofloxacin is a relatively new fluoroquinolone with excellent activity against Pseudomonas and methicillin-resistant Staphylococcus aureus. Recent studies have shown oral ciprofloxacin to be effective in the treatment of chronic serous otitis media and malignant external otitis. However, this drug has never been used as a topical otic preparation. Thirty-five albino female guinea pigs were used to investigate the ototoxicity of topical ciprofloxacin hydrochloride. Bilateral transbullae drug delivery tubes were placed and auditory brain-stem response thresholds were recorded at 20, 16, 8, and 4 kHz before treatment and 21 days after the completion of treatment. Two groups of guinea pigs were used. In group 1 (positive controls), five guinea pigs had 0.1 mL of neomycin sulfate administered in one ear while the opposite (control) ear received 0.1 mL of 0.9% sodium chloride solution; in group 2, 30 guinea pigs received 0.75% ciprofloxacin ophthalmic solution and 0.9% sodium chloride solution in the control ear. All drugs were given twice a day for 7 consecutive days. All results were evaluated with paired, two-tailed t test and Hotelling's T2 test, and calculation of power was performed on all nonsignificant results. No significant ototoxic reaction was observed; small increases in hearing thresholds occurred at 4 (5.65±8.25 dB [mean±SD]) and 8 kHz (3.70±6.63 dB [mean±SD]) in the ciprofloxacin-treated ears; however, no significant hair-cell loss was seen. Therefore, the hearing loss appears to be due to middle-ear mucosal changes. The planning and analysis of negative experimental trials is discussed, and a model for testing potentially nonototoxic drugs is presented.

(Arch Otolaryngol Head Neck Surg. 1992;118:392-396)

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