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Ototoxicity of an ototopic preparation--experimental results and clinical facts
A R Halama1, C G Wright, W L Meyerhoff
1Department of Otorhinolaryngology, Head/Neck Surgery, Akademisch Ziekenhuis, Vrije Universiteit Brussel, Belgium.
Abstract:
The ototoxicity of "Cortisporin Otic Suspension" containing 3.5 ml neomycin base, 10,000 units/ml polymyxin B was studied using the baboon (papio ursinus) as an experimental animal. Inner and outer hair cell loss occurred in all cochleas of the ears which received cortisporin. Most lesions were confined to the basal turn of the organ of Corti. Separate evaluation of polymyxin B and neomycin at the same concentration as in cortisporin showed that polymyxin B produced greater cochlear damage. The results of this study and clinical reports of sensorineural hearing loss due to commercially available ear drops indicate that ototopical preparations must be used with caution in clinical situations in which they may reach the middle ear.
Insights
Cortisporin Otic Suspension can cause hearing loss. This study found polymyxin B in the ear drops caused significant cochlear damage in baboons, highlighting the ototoxicity risks.
Area of Science:
- Ototoxicity research
- Pharmacology of ear medications
- Auditory system investigation
Background:
- Cortisporin Otic Suspension is a common ear drop formulation.
- Concerns exist regarding the ototoxic potential of topical ear medications.
- Neomycin and polymyxin B are active ingredients in Cortisporin.
Purpose of the Study:
- To investigate the ototoxicity of Cortisporin Otic Suspension.
- To evaluate the individual contributions of neomycin and polymyxin B to cochlear damage.
- To assess the safety of topical ear drops in clinical settings.
Main Methods:
- Utilized the baboon (Papio ursinus) as an animal model.
- Administered Cortisporin Otic Suspension to the ears of baboons.
- Examined cochlear tissues for hair cell loss and other lesions.
- Separately tested polymyxin B and neomycin at equivalent concentrations.
Main Results:
- All baboon cochleas treated with Cortisporin showed inner and outer hair cell loss.
- The majority of observed lesions were concentrated in the basal turn of the organ of Corti.
- Polymyxin B demonstrated greater cochlear damage compared to neomycin at the same concentrations.
Conclusions:
- Cortisporin Otic Suspension exhibits significant ototoxicity.
- Polymyxin B is a primary contributor to the observed cochlear damage.
- Clinicians should exercise caution when prescribing topical ear preparations that may access the middle ear.