I HAD to use fluoxetine in order to keep a stray cat (Stanley) we found dumped in our neighborhood. When we found him he had been declawed on ALL FOUR PAWS. He was a total sweetheart with our human family, but hated our other cat, and 2 labs. He started peeing in our house. Trust me when I say that we tried EVERYTHING-

multiple litterboxes scooped multiple times daily
Full checkup and labs costing hundereds of dollars
kept him separate and did the SLOW intro, etc.

When all else failed my vet suggested Fluoxetine. It saved Stanley's life. He wouldn't take a pill so we had it compounded into liquid form ( fish flavored) and put it into his food daily. We saw no side effects, except he was a little stoned for the first few days. The peeing stopped almost immediately. I know there are many who are against this type of drug, but it was a miracle for my family.
Good Luck and keep us posted!

I had a cat that was on valium for several yrs. She started urinating on furniture suddenly at about 3 yrs. Had been quite ill as a kitten & I think had some physical problems that we never got to the root of. I know we spent literally thousands on tests, vet visits, and mostly, furniture she ruined.

We finally ended up w/her on a low dose of valium twice a day, and she was locked in a bedroom overnight every night, with 2 litter pans food & water. I usually sat w/her at night for a few hrs too. Night was when she did most of her damage. She was pretty loopy at first but it helped. We even got her off it once over a long period of decreasing dosage & frequency, but she started peeing again soon afterwards.

Finally after about 5 yrs we put her down, I couldn't take it any more. I had a cat ruining my house because I felt bad, like I needed to do everything to save her. And I really loved her, it was awful all around.

The meds were cheap, we did have to get her blood checked maybe twice a yr for liver damage, iirc. Good luck I hope it works out for you.

Treated a lot of cats with Fluoxetine... so far never seen a problem nor even a change in lab work... doesn't ALWAYs work for all behavioral problems, but by far the most effective of all the behavioral drugs I have used on cats (and that is about 6 or 7). Works pretty fast unlike how it works on people (can take over a month to start working on us).

My cat has been on amitriptyline for about 8 months; first 5 mg/day (which reduced the peeing incidents for a while), then 10 mg when he started blitzing the house again.

He has been checked monthly for cystitis, had a bladder scan, etc. and the vet thinks it may be a chronic cystitis situation with a behavioral component. In other words, he started peeing outside the box due to the cystitis and now just keeps doing it.

He is also on Cosequin and presciption canned food for the chronic cystitis. The Amitripyline is a transdermal that I rub inside his ear flap. I think it has helped him with his phobias (he has several: ceiling fans, skylights) and he definitely doesn't act dopey even on the higher dose, but clearly it's not helping with the peeing.

I am calling the vet today to ask about switching to Prozac because it's getting to be much too much; every day, sometimes twice a day is just too much.