My kitty has Idiopathic cystitis. I was previously feeding her an all dry Hills prescription diet before this started, but have since switched her to all canned diet and she seems to be doing better since switching, at least so far. She is peeing big pees now, much larger than she ever has. The vet prescribed Hills CD canned - expensive and kitty is lukewarm about it (doesn't gobble, eats it very slowly) so I bought some Pro Plan Focus Urinary canned which she seems to like a lot better. I have been giving her both because I am afraid to take her off the prescription canned. Is mixing the two foods bad? How does the Pro Plan compare to prescription and is it risky to take her off prescription and just feed all Pro Plan focus canned? Other options/dietary advice for this condition? TIA!!!