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.