If your kitty has interstitial cystitis, highly acidified cat foods and extra urinary acidifiers can irritate the bladder lining more. Just want to make sure you are aware of that possibility. The Cosequin is supposed to help heal the lining of the bladder so it has that protective layer it should have.
You should talk to your vet about the possibility that it is IC and what your options are.
You should talk to your vet about the possibility that it is IC and what your options are.