Enrofloxacin in the cat: blindness from retinal degeneration
12-year-old cat with chronic kidney disease treated with enrofloxacin above the licensed dose for a urinary infection. After 10 days it is blind, with bilateral mydriasis and no pupillary light reflexes, and fundoscopy shows diffuse tapetal hyperreflectivity and attenuated retinal vessels. Normal blood pressure.
What is the most likely diagnosis?
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A. Hypertensive retinal detachment
Blood pressure is normal and the fundus shows no detached retina or haemorrhages, but tapetal hyperreflectivity and vascular attenuation.
B. Sudden acquired retinal degeneration syndrome (SARDS)
SARDS is a disease of dogs, with an initially normal fundus; it does not explain the drug history in a cat.
C. Diffuse retinal degeneration due to fluoroquinolones, favoured by the high dose and kidney disease
Correct. Cats have a defect in a transporter (ABCG2) that allows fluoroquinolones to accumulate in the retina. A high dose and reduced renal clearance increase the risk, and the blindness is usually irreversible.
D. Bilateral optic neuritis
In optic neuritis the retina is usually normal and the optic disc may appear swollen; diffuse tapetal hyperreflectivity indicates retinal degeneration.
lightbulb Key takeaway
In cats do not exceed 5 mg/kg/day of enrofloxacin, adjust the regimen in kidney disease and, if you need a fluoroquinolone, prefer those with a wider margin in this species (marbofloxacin, pradofloxacin). Ask the owner to watch for signs of blindness or mydriasis.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.