Why Hasn’t my Cat’s Bladder Infection Cleared up?
My 12-year-old male cat was diagnosed with a urinary tract infection and prescribed Clavamox. He has had two days of meds plus his pain med. I was told he did not have crystals in his urine, just blood, he is now trying to urinate in odd places and his bowel movements are runny and he is using his litter box for those. Shouldn’t he be better by now and urinating in his box?
Julie
Knoxville, TN
Urinary tract infections, or bladder infections, commonly cause bloody urine and house soiling in cats. But other problems can cause these symptoms as well.
Bladder infections generally show marked improvement during the first 24 to 48 hours of treatment. Clavamox is effective against most bladder infections. If your cat’s condition hasn’t improved after two days on the medicine, I am worried that something other than a bladder infection might be going on.
Bladder stones, bladder tumors, and chronic irritation of the bladder can cause bloody urine and house soiling in cats. Blood clotting problems, infections with resistant strains of bacteria, and trauma are less frequent causes of these symptoms.
I recommend that you visit the vet again for more tests such as X-rays and abdominal ultrasound. These are the next steps in solving your cat’s urinary problems.
Your cat’s diarrhea probably is a side effect of the Clavamox. All antibiotics can cause upset stomach or diarrhea. This problem is likely to get worse if you keep administering the Clavamox.
You have questions. 
Freckles is on Clavamox for a different type of infection and although it caused diarrhea for a couple of days that quickly got better. If your cat still has symptoms you can ask your vet to culture his urine to check to see if the bacteria is resistant to Clavamox and retest for crystals etc in case its something else.