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How Long Does it Take for Clavamox to Work in Dogs and Cats?

How Long Does it Take for Clavamox to Work?

Our question this week was:

Hi Dr. Debra,

I have a quick question. I have a male cat of about 2 years old. Took him to the vet because he had problems urinating. He prescribed Clavamox® for treatment.

My question is how long does it take before it starts working. Because I was told that his urine has crystallized. He has already takes his second dose. Is this enough for him to start recovering?

Deborah Hendricks


Thanks for your question. Clavamox is an antibiotic commonly used to treat infections of the urinary tract, skin and soft tissue in dogs and cats. The onset of action of Clavamox is pretty quick. It is readily absorbed and reaches a good blood concentration in about 1 hour. However, it make take longer to fully reach the urinary tract and effectively treat an infection. I’d give the antibiotic a little more time. In the mean time, make sure your kitty is eating and drinking well. Offer plenty of fresh clean water. Top off the water bowl to encourage him to drink. This is important – make sure he is urinating. If he is staining, not producing urine, doesn’t want to eat or drink, vomits, or acts lethargic, call your veterinarian immediately. The concern is that he could have a urinary obstruction if you see these symptoms.

Cats can get other conditions that resemble urinary track infections including urinary blockages or “stones”. If he is not doing well or you are concerned, the safest thing is to call your vet and have him re-examined.

I hope the Clavamox helps him soon!

Best of luck!

Dr. Debra

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