How Long can Cats Take Zeniquin (Marbofloxacin)?


Hello Dr. Barchas,

My question is about giving my cat, a 12-year old with chronic renal failure, Zeniquin (12 mg.) on a daily basis. He has been on it for one month; our vet is running another urine culture but advised keeping him on it indefnitely because we noticed his appetite dropped off significantly when we stopped it (after 1st month).

Have you heard of it being used for more than one month this way? could it damage his retinas? Thank you in advance for any input.


I’m generally opposed to any long term medication that does not lead to a clear benefit for the patient. A 12-year-old cat with kidney failure certainly would be a high risk candidate for a chronic low grade bladder or kidney infection that might respond to Zeniquin (which is an antibiotic related to ciprofloxacin, also known as cipro). If you have noticed that your cat’s appetite is better while on the medicine, a bladder infection (or the placebo effect, which does occur in animals when owners perceive an improvement that isn’t actually linked to the medication in use) would be the most likely explanation. A urine culture is considered the best way to test for bladder infections, but some types of kidney infections will not show up in urine cultures.

If your cat’s urine culture is clean, I would try discontinuing the medication again to see whether appetite is affected. If your cat will only eat well while on the medication, then I recommend continuing the medication. However, I would prefer that he not take it unless he truly benefits from it.

Zeniquin, like cipro and Baytril (two related medications), is excreted by the kidneys and must be used cautiously in cats with kidney failure. However, its use is not inappropriate in cats with kidney failure. Baytril (enrofloxacin) has been linked to retinal damage and blindness in high doses in some especially susceptible cats. Zeniquin appears to have a dramatically lower potential to cause retinal toxicity. It is not likely that the medication will damage your cat’s eyes, but I still don’t recommend using it continuously unless you have a good cause.

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