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Treatment of severe external otitis with enrofloxacin
PA G E 6
A D VA N C E S
Procedure Thirty dogs were randomized to an enrofloxacin-treatment group (5, 10, 15, or 20 mg/ kg) or control group (no enrofloxacin). After surgical removal, samples of ear skin, vertical ear canal, horizontal ear canal, middle ear, and blood were collected. Concentrations of enrofloxacin and ciprofloxacin in the plasma and ear tissue were then measured.
Results Ear tissue concentrations of enrofloxacin and ciprofloxacin were significantly higher than plasma concentrations. Each 5 mg/kg increase in the dose of enrofloxacin resulted in a 72% and 37% increase in enrofloxacin and ciprofloxacin concentrations, respectively. For bacteria with an minimal inhibitory concentration (MIC) of 0.12 ± 0.15 or less, 0.19 ±0.24, 0.31 ±0.39, and 0.51 ±0.64 μg/ml, enrofloxacin should be dosed at 5, 10, 15, and 20 mg/kg, respectively.
TREATMENT OF SEVERE EXTERNAL OTITIS WITH ENROFLOXACIN Background Otitis externa is the most commonly diagnosed ear disease in dogs. Otitis media can be a perpetuating cause of recurrent otitis externa. The two most common bacterial pathogens of dogs with chronic otitis externa and otitis media are Staphylococcus intermedius and Pseudomonas aeruginosa. Enrofloxacin has bactericidal activity against both S. intermedius and P. aeruginosa. The primary metabolite of enrofloxacin is ciprofloxacin. Ciprofloxacin also has antibacterial activity against gram-negative bacteria including P. aeruginosa, which is additive with enrofloxacin. Dogs with pyoderma have significantly higher skin levels of enrofloxacin than dogs without pyoderma. However, tissue concentrations of enrofloxacin and ciprofloxacin in the skin of the ear, vertical ear canal, horizontal ear canal, and middle ear of dogs with chronic otitis externa and concurrent otitis media after administration of enrofloxacin are not known.
Objectives To measure the concentrations of enrofloxacin and ciprofloxacin in the plasma and ear tissue of dogs with chronic endstage otitis that were administered IV enrofloxacin and had a total ear canal ablation and lateral bulla osteotomy.
Author Conclusion Because of concentration in the skin of the ear, enrofloxacin is effective treatment for bacterial pathogens of the ear canal if the organisms are clearly susceptible to enrofloxacin. Treatment with enrofloxacin should not be recommended for a bacterial organism intermediate or resistant in susceptibility to enrofloxacin since appropriate, high concentration levels of enrofloxacin would not be attained.
Inclusions Seven tables, 34 references.
Editor Annotation Bacteria are considered to be secondary pathogens in dogs with chronic ear infections. However, elimination of these secondary pathogens is required to prevent further pathological changes in the ear canals and to relieve the clinical symptoms of ear disease. Fluroquinolones are popular medications for use in treating ear infections, due to their broad spectrum of activity against pathogenic microorganisms and their excellent penetration into inflamed tissues. Some veterinarians advocate using only topical medications in treating ear infections, while others prescribe a combination of topical and systemic antimicrobial medications. This study documented significantly higher concentrations of enrofloxacin and its active metabolite, ciprofloxacin, in the
ear tissues of dogs with otitis externa and lower concentrations in their plasma. Increasing the dose of enrofloxacin resulted in an exponential increase in tissue concentrations of both enrofloxacin and ciprofloxacin. The results provide support of the use of enrofloxacin in the treatment of ear infections in dogs. The authors provided recommended doses to achieve appropriate tissue concentrations of antibiotic based upon the MIC of the microorganisms isolated from the ear canal. (KLC) Cole LK, Papich MG, Kwochka KW, et al. Plasma and ear tissue concentrations of enrofloxacin and its metabolite ciprofloxacin in dogs with chronic end-stage otitis externa after intravenous administration of enrofloxacin. Vet Dermatol 2009;20:51-59.
A D VA N C E S
Procedure Thirty dogs were randomized to an enrofloxacin-treatment group (5, 10, 15, or 20 mg/ kg) or control group (no enrofloxacin). After surgical removal, samples of ear skin, vertical ear canal, horizontal ear canal, middle ear, and blood were collected. Concentrations of enrofloxacin and ciprofloxacin in the plasma and ear tissue were then measured.
Results Ear tissue concentrations of enrofloxacin and ciprofloxacin were significantly higher than plasma concentrations. Each 5 mg/kg increase in the dose of enrofloxacin resulted in a 72% and 37% increase in enrofloxacin and ciprofloxacin concentrations, respectively. For bacteria with an minimal inhibitory concentration (MIC) of 0.12 ± 0.15 or less, 0.19 ±0.24, 0.31 ±0.39, and 0.51 ±0.64 μg/ml, enrofloxacin should be dosed at 5, 10, 15, and 20 mg/kg, respectively.
TREATMENT OF SEVERE EXTERNAL OTITIS WITH ENROFLOXACIN Background Otitis externa is the most commonly diagnosed ear disease in dogs. Otitis media can be a perpetuating cause of recurrent otitis externa. The two most common bacterial pathogens of dogs with chronic otitis externa and otitis media are Staphylococcus intermedius and Pseudomonas aeruginosa. Enrofloxacin has bactericidal activity against both S. intermedius and P. aeruginosa. The primary metabolite of enrofloxacin is ciprofloxacin. Ciprofloxacin also has antibacterial activity against gram-negative bacteria including P. aeruginosa, which is additive with enrofloxacin. Dogs with pyoderma have significantly higher skin levels of enrofloxacin than dogs without pyoderma. However, tissue concentrations of enrofloxacin and ciprofloxacin in the skin of the ear, vertical ear canal, horizontal ear canal, and middle ear of dogs with chronic otitis externa and concurrent otitis media after administration of enrofloxacin are not known.
Objectives To measure the concentrations of enrofloxacin and ciprofloxacin in the plasma and ear tissue of dogs with chronic endstage otitis that were administered IV enrofloxacin and had a total ear canal ablation and lateral bulla osteotomy.
Author Conclusion Because of concentration in the skin of the ear, enrofloxacin is effective treatment for bacterial pathogens of the ear canal if the organisms are clearly susceptible to enrofloxacin. Treatment with enrofloxacin should not be recommended for a bacterial organism intermediate or resistant in susceptibility to enrofloxacin since appropriate, high concentration levels of enrofloxacin would not be attained.
Inclusions Seven tables, 34 references.
Editor Annotation Bacteria are considered to be secondary pathogens in dogs with chronic ear infections. However, elimination of these secondary pathogens is required to prevent further pathological changes in the ear canals and to relieve the clinical symptoms of ear disease. Fluroquinolones are popular medications for use in treating ear infections, due to their broad spectrum of activity against pathogenic microorganisms and their excellent penetration into inflamed tissues. Some veterinarians advocate using only topical medications in treating ear infections, while others prescribe a combination of topical and systemic antimicrobial medications. This study documented significantly higher concentrations of enrofloxacin and its active metabolite, ciprofloxacin, in the
ear tissues of dogs with otitis externa and lower concentrations in their plasma. Increasing the dose of enrofloxacin resulted in an exponential increase in tissue concentrations of both enrofloxacin and ciprofloxacin. The results provide support of the use of enrofloxacin in the treatment of ear infections in dogs. The authors provided recommended doses to achieve appropriate tissue concentrations of antibiotic based upon the MIC of the microorganisms isolated from the ear canal. (KLC) Cole LK, Papich MG, Kwochka KW, et al. Plasma and ear tissue concentrations of enrofloxacin and its metabolite ciprofloxacin in dogs with chronic end-stage otitis externa after intravenous administration of enrofloxacin. Vet Dermatol 2009;20:51-59.