Side effects of repeated ototopical application of fosfomycin. An animal study.

In view of the possible role of fosfomycin in the topical treatment of chronic suppurative otitis media, the effects of this drug on inner ear function were investigated. Fosfomycin (20% aqueous solution) was applied repeatedly to the round window membrane of both ears of pigmented guinea pigs. Hearing thresholds were determined by daily frequency-specific evoked response audiometry with stimulation frequencies ranging from 1 to 32 kHz. Both positive (neomycin) and negative (saline) controls were included. Results were analyzed statistically. No significant and progressive hearing loss was found with fosfomycin. At 32 kHz, however, the hearing levels at the end of the test period were significantly worse in the fosfomycin group than in the saline group.