Investigation of topical ciprofloxacin ototoxicity in guinea pigs

Antibiotic eardrops mostly contain potentially ototoxic aminoglycosides. Ci profloxacin is an alternative, and there is limited experience in its topic al use. To investigate the topical ototoxicity of ciprofloxacin, 11 guinea pigs have been operated on. Transbullae silicone drug delivery tubes were p laced to both ears of the animals. After the operation the guinea pigs were divided into two groups. The first group of animals received 0.2 mi of 4% gentamicin in one ear and 0.2 mi of 0.9% sodium chloride solution in the ot her. The second group received 0.2 mi of 0.2% ciprofloxacin in the test ear and 0.2 mi of 0.9% sodium chloride solution in the control ear. All drugs acre given once a day on 7 consecutive days. Auditory brainstem response th resholds were recorded using click, 4 and 8 kHz logon stimuli before and af ter the operation, and after topical drug application. Results were statist ically compared using Wilcoxon matched pairs signed-ranks test. Comparison of the thresholds before and after the operation, physiological saline appl ication, as well as ciprofloxacin application yielded no statistically sign ificant differences, whereas application of gentamicin resulted in total he aring loss. The results indicate that topical use of 0.2% ciprofloxacin is not ototoxic in guinea pigs.