Updated On September 23rd, 2025
Pet's info: Cat | American Shorthair | Male | neutered | 1 year and 2 months old | 12 lbs
My 1 year old male cat is on clavamox for a mild upper respiratory infection, he started the meds yesterday and has gotten much worse, drooling and foaming excessively from the mouth and his fur is all matted. He has not eaten today and is just hiding in an enclosed cat bed.
1 Answer
Published on October 17th, 2017
It can take several days for an antibiotic to take effect against a bacterial infection, but not all upper respiratory infections are bacterial in origin. Many are actually viral which will have to run their course with supportive care. The drooling and foaming at the mouth can sometimes be seen shortly after administering oral medications such as Clavamox since they taste badly to cats. Matted fur could be caused by not feeling well enough to groom. Not eating is common in cats that can't smell well since they are smell-driven when eating. I would recommend that you try to give Sam water or pedialyte to stay hydrated, and try "smelly" cat food such as canned cat food or canned tuna. If he isn't better tomorrow, becomes profoundly lethargic, or you cannot get food or water into him, then he should be re-evaluated by your vet for other treatment options or even hospitalization.
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