Baytril, Blindness, and Your Cat

By Shawn Messonnier DVM
A resource from Pet-Togethers

Antibiotics are often used in the treatment of various feline diseases. Due to over-use of antibiotics, bacteria can develop resistance to frequently used antibiotics; as a result, antibiotics become less effective over time, and may even become ineffective. To counter antibiotic resistance, pharmaceutical companies are constantly trying to find new medications to help win the war against deadly bacteria. One such recently introduced antibiotic is Baytril (enrofloxacin.) While Baytril is very effective against many bacteria, unfortunately it is often being used as a first choice antibiotic in many situations. While antibiotic resistance is now developing against Baytril, a new side effect (blindness) has been reported in some cats. This article will discuss this problem, and will also offer some alternatives to consider that can be equally effective against bacterial infections without causing this severe problem.

Over the last few months there have been a few rare reports of blindness in cats caused by administration of the antibiotic Baytril (enrofloxacin.) A timely report in the December 2002 issue of the Journal of the AVMA summarized the problem and reviewed a retrospective study of 17 affected cats. The affected cats ranged from 3-16 years of age and were treated with Baytril for a variety of medical problems. In the affected cats, the retinas of the eyes had degenerated following treatment for a variety of disorders with Baytril. The suspected mechanism of damage seems to be direct damage to the retinal cells. In most cats, the dosage of Baytril exceeded 5 mg/kg per day and the blindness was irreversible. Older cats developed blindness at lower dosages than what was needed to cause blindness in the younger patients. Older cats often have underlying kidney disease; if Baytril doses are not lowered, increased blood levels can accumulate due to inadequate kidney function. Currently, based upon the cases studied, it appears that the greatest risk factors are the dose of Baytril administered, the length of treatment (the longer the cat is treated the greater the risk of developing blindness,) age of the cat (it appears to be potentially more toxic to the retinas of older cats,) and rapid IV administration of the medication. While there have been no official reports of this problem in dogs, I have treated one dog whose owner came to me for a second opinion. This was an older small breed dog that had developed sudden blindness following Baytril administration for an oral cyst. Despite extensive testing and referral to an ophthalmologist, the exact cause of the blindness was never determined. Administration of Baytril immediately prior to the dog developing blindness was the only known link to the blindness.

While the risk of irreversible retinal degeneration and subsequent blindness is estimated to be 1 out of 122,414 cats treated with Baytril, there are other options to consider. First, if antibiotic therapy is needed, a different antibiotic should be chosen unless the situation is so severe that only enrofloxacin would be indicated. For example, amoxicillin, clindamycin, trimethoprim sulfa, tetracycline derivatives, and any of the cephalosporin antibiotics could be used without danger of retinal degeneration. Whenever possible, a natural alternative to antibiotic therapy would be preferred. As an example, cats with mild, non-bloody urinary disease (FLUTD) may benefit from herbs such as cranberry and homeopathics rather than antibiotics. Cats with chronic respiratory conditions (especially herpes virus infection) can be maintained (but not cured) with a combination of other antibiotics, immune boosting herbs, and topical saline nose drops and sometimes decongestants. Pets with skin infections often do quite well with frequent bathing with antibacterial shampoos, antibacterialolive leaf extract, and various immune stimulants such as Echinacea, astragalus, and colostrum.

My current recommendations are as follows: First, use Baytril only if another medication would not be suitable to treat the infection. In general, Baytril can be reserved for serious acute or difficult-to-treat chronic infections. Second, whenever possible, use a natural antibiotic-alternative for mild infectious problems, such as some of the supplements recommended earlier in this article. Extra caution is warranted in geriatric cats, especially those with underlying dehydration or kidney disease (the dosage of Baytril in the blood is increased in the presence of reduced kidney function.) In cats, I try to avoid any dose over 5 mg/kg per day, and only use Baytril if absolutely needed for as short a period as possible. By combining Baytril (when indicated) with natural therapies and fluid supplementation as needed, I can reduce the amount of Baytril needed and minimize chances for side effects.

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