Degeneração de retina associada a enrofloxacina em gatos / Enrofloxacin-associated retinal degeneration in cats

Enrofloxacin-associated retinal degeneration in cats

1. Kirk N. Gelatt^1,*, 
2. Alexandra Van Der Woerdt², 
3. Kerry L. Ketring³, 
4. Stacy E. Andrew¹,
5. Dennis E. Brooks¹, 
6. Daniel J. Biros¹, 
7. Heidi M. Denis¹, 
8. Timothy J. Cutler¹

Article first published online: 21 DEC 2001

DOI: 10.1046/j.1463-5224.2001.00182.x

Issue

Veterinary Ophthalmology

Volume 4, Issue 2, pages 99–106, June 2001

Additional Information(Show All)

Keywords:

• enrofloxacin;
• feline;
• retinal degeneration

Abstract

Objective

The objective of this study was to evaluate the possible relationship between the administration of parenteral enrofloxacin and the onset of acute retinal degeneration in cats. The animals studied included 17 cats that received systemic enrofloxacin and developed retinal degeneration soon thereafter.

Procedures

In this retrospective clinical study, cats that received parenteral enrofloxacin and developed acute blindness were identified. Parameters recorded included breed, age, sex, enrofloxacin dosage (daily dose and number of days administered), medical condition for which the antibiotic had been prescribed, ophthalmic signs, examination results, and the visual outcome. Fundus photographs were obtained in seven cats, and electroretinography was performed in five cats. Histopathology was performed on two eyes from one cat (case 1) that received enrofloxacin 5 months previously and developed retinal degeneration.

Results

All cats were the domestic shorthair breed; seven were females (one neutered) and ten were males (seven castrated). Ages ranged from 3 to 16 years old (mean ± SD; 8.8 ± 4.6 years). The medical disorders for which enrofloxacin was administered ranged from lymphoma and pancreatitis to otitis and dermatitis, and eight cats had urinary diseases. The daily and total dosage of enrofloxacin and number of days of administration were also highly variable. Presenting clinical signs were most often mydriasis and acute blindness. All cats had diffuse retinal degeneration as evidenced by increased tapetal reflectivity and retinal vascular attenuation. Absence of recordable electroretinographic responses suggested diffuse and extensive outer retinal disease. Vision returned in a few cats, but the retinal degeneration persisted or even progressed. Histopathology of two eyes revealed primarily outer retinal degeneration, with diffuse loss of the outer nuclear and photoreceptor layers, and hypertrophy and proliferation of the retinal pigment epithelium.

Conclusion

Parenteral enrofloxacin is potentially retinotoxic in some cats, and may result in acute and diffuse retinal degeneration. Blindness often results, but some cats may regain vision. Practitioners should adhere closely to the manufacturer’s current enrofloxacin dosage recommendation (5 mg/kg q 24 h), and continue clinical observations for this drug toxicity in cats.