Brainstem auditory evoked responses in 37 dogs with otitis media before and after topical therapy

Abstract

OBJECTIVES : The objective of this study was to determine whether intra-aural administration of aqueous solutions of marbofloxacin, gentamicin, tobramycin and ticarcillin (used off-licence) was associated with changes in hearing as measured by brainstem auditory evoked responses.MATERIALS AND METHODS : Dogs diagnosed with otitis media (n=37) underwent brainstem auditory evoked response testing and then were treated for their ear disease. First, the external ear canal and middle ear were flushed with sterile saline followed by EDTA tris with 0·15% chlorhexidine. Then, a combination of aqueous antibiotic mixed with an aqueous solution of EDTA tris was instilled into the middle ear.Follow-up examinations were undertaken for each dog, and treatment was continued until there were no detected infectious organisms or inflammatory infiltrate. Brainstem auditory evoked response testing was repeated after resolution of the infection and discontinuation of therapy.RESULTS : Brainstem auditory evoked responses in dogs treated with aqueous solutions of marbofloxacin or gentamicin remained unchanged or improved after therapy of otitis media but were impaired in dogs treated with ticarcillin or tobramycin.CLINICAL SIGNIFICANCE : If off-licence use of topical antibiotics is deemed necessary in cases of otitis media, aqueous solutions of marbofloxacin and gentamicin appear to be less ototoxic than aqueous solutions of ticarcillin or tobramycin.

Antibacterial effect of N‐acetylcysteine in combination with antimicrobials on common canine otitis externa bacterial isolates

“…Antioxidant therapy by means of NAC administration is one approach used clinically to mitigate the potential for aminoglycoside ototoxicity in humans . Albeit uncommon in dogs, aminoglycoside‐associated ototoxicity can be observed in dogs treated for otitis externa . Combining the antimicrobial and otoprotective activity of NAC with the antimicrobial activity of gentamicin could potentially result in a successful treatment option without the risk of hearing loss; however, in the present study, a beneficial antimicrobial effect was not consistently observed.…”

Otitis media with effusion in the boxer: a report of seven cases

“…A combination of EDTA tris, enrofloxacin and dexamethasone was used as topical treatment in these boxers. This combination, which constitutes an off‐licence use of the drugs, has been found to be very safe in cases of OM (Paterson & Payne 2008, Harvey & Paterson 2014). The negative cytology from the middle ears in these boxers was thus not taken as an indication of sterility until confirmed by culture.…”

Topical ear treatment – options, indications and limitations of current therapy

“…Canine studies to assess the use of gentamicin in OM have shown no noticeable degree of cochlear or vestibular ototoxicity (Strain et al . , Paterson & Payne ). Other topical aminoglycosides such as tobramycin, as well as the semi‐synthetic penicillin ticarcillin, have been associated with severe hearing loss when used to treat OM (Paterson & Payne ).…”

“…Other topical aminoglycosides such as tobramycin, as well as the semi‐synthetic penicillin ticarcillin, have been associated with severe hearing loss when used to treat OM (Paterson & Payne ). Aqueous solutions of fluoroquinolones including enrofloxacin and marbofloxacin appear to be safe when used in the canine middle ear (Paterson & Payne , Paterson ). Conflicting information appears to be available regarding the use of topical azoles in cases of OM.…”