title: Ototoxicity of Povidone-Iodine applied to the middle ear cavity of guinea pigs.
abstract: OBJECTIVE
  Povidone-Iodine preparation is used as a disinfectant in otological surgeries. The ototoxicity of Povidone-Iodine preparation was evaluated using infant, young and adult guinea pigs. The effects of different concentrations and of different exposure durations on compound action potentials were also studied.
  
  
  METHODS
  Povidone-Iodine was used to fill one middle ear cavity of the guinea pig, and the compound action potential (CAP) was measured from the round window membrane at 24h, 7 days, and 28 days. The contralateral side was filled with saline as control. Test sounds used were clicks and tone bursts of 2, 4, and 8 kHz.
  
  
  RESULTS
  At 24h, Povidone-Iodine solution showed a significant toxic effect in the infant group. In the young animal group, no toxic effect was seen. In the adult group, a mild degree of deafness for 2 kHz was found. At 7 days, the young group showed significant hearing loss for all frequencies, but the adult group did not show any hearing loss. With a half strength solution, both young and adult group did not show hearing loss. At 28 days, with a full strength solution, hearing loss became prominent for all sound stimulation. With 1/8th dilution, the young group showed a moderate hearing loss, but the adult group did not.
  
  
  CONCLUSIONS
  The thicker round window membrane in human is expected to provide more protection to the human cochlea than in the guinea pig model that we have studied. Mild hearing loss at 24h and 7 days using 10% solution, but no hearing loss with 5% solution at 7 days may indicate that rinsing of the middle ear cavity with saline during surgery should minimize the ototoxic effect of this product. The age of the animals does influence the outcome of the ototoxicity experiment. From this experiment, Povidone-Iodine preparations in the infant should be used with caution. Povidone scrub should not be used for otologic surgery.
authors: Department of Otolaryngology, Fukuoka University School of Medicine Nanakuma, Jonan-ku, Fukuoka City, Japan.
authors: T
authors: T
authors: Ichibangase
authors: T
authors: T
authors: Yamano
authors: M
authors: M
authors: Miyagi
authors: T
authors: T
authors: Nakagawa
authors: T
authors: T
authors: Morizono
mesh_terms: D000287:Administration, Topical; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D000891:Anti-Infective Agents, Local / Q000494:pharmacology / Q000633:toxicity*; D003638:Deafness / Q000139:chemically induced / Q000175:diagnosis / Q000453:epidemiology; D004195:Disease Models, Animal; D004432:Ear, Middle / Q000187:drug effects*; D006168:Guinea Pigs; D034381:Hearing Loss / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology; D006320:Hearing Tests; D015994:Incidence; D011206:Povidone-Iodine / Q000494:pharmacology / Q000633:toxicity*; D011897:Random Allocation; D012016:Reference Values; D018570:Risk Assessment
chemical_list: D000891:Anti-Infective Agents, Local; D011206:Povidone-Iodine