Amitryptilene worked for my cats for a little while but then they started up again. I've heard good things about kitty Prozac but mine are on Clomicalm, which is usually for dogs, but they've had no side effects whatsoever and what's better, no peeing. If Clomicalm should stop working, I'll give Prozac a whirl. I feel for ya; I know how difficult it can be but we can't let our homes be peed on. We live here. Let us know how it works for ya.