I'm at a point with one of my cats where I'm not sure what else to try or if this is something I'm just going to have to live with.
We rescued Dexter three years ago after his owners stopped feeding him and letting him inside. He was over a year old and pretty beat up, so we took him home, got him neutered and all cleaned up. But I think because he had been neutered so late, and had been surviving in the outdoors, he had picked up the habit of spraying/marking, and never got out of it.
He was into the vet for urine tests and other check-up stuff after a few months of the spraying, and everything was clear there, the vet said it was definitely behavioral and not medical.
The vet tried him on an anti-anxiety pill for a few months, and this didn't help. Since then, over the past two years, we've tried him on Feliway, as well as another type of pheromone diffuser, and an anti-anxiety collar. None of these seemed to make much of a difference.
We clean the areas he is spraying with Nature's Miracle, and we have a blue light thing to help us find any spots we may have missed.
The trigger seems to be ANYTHING happening outside. He is indoors only and shows no desire to go outside, but he likes looking out the window. But if a cat walks by or a bird is irritating him, etc., he gets stressed out and sprays.
When I'm home to catch it, he gets aggravated for a bit, meowing and pacing, before he sprays.
Other than this, he is a completely happy cat. We have four cats and they are all buddies. He grooms with the other cats, cuddles them, plays with them, etc. He gets tons of love.
They eat Orijen. Litterbox is cleaned every day. He has lots of fun toys and a gigantic cat tree. He sleeps with his tummy up a lot and sits on my lap for cuddles. He is a fabulous sweet cat, but he sprays at least weekly, and sometimes multiple times daily.
Is there anything I am missing? I'm going to make it work regardless, and I'm thinking of taking him back to the vet for more advice, but I'm not sure what else they can suggest.
I don't know what medication your vet used, but there are several and just because one didn't work doesn't mean another won't.
You said "litterbox" (singular). If you have 4 cats, you should have 5 litter boxes.
Do the litter boxes have hoods on them? Remove them. Are they all in the same location? Separate them and make sure they are all over the house. Do you use liners? Get rid of them. Have you tried using different types of litter? Try different ones in different pans. Sometimes a cat prefers a pan without any litter.
Do not punish or interrupt your cat when he is spraying. Negative punishment makes cats worse. Positive reinforcement improves cat behavior. When you see him using the litter box, reward him AFTER he has just left the box with verbal praise, treats, and petting.
Continue the Feliway and collars and toys and play and cuddling.
Have another urinalysis performed and bloodwork also if that hasn't been done recently.
Can you keep him away from windows so he can't see other animals and birds?
As a last resort, cats may be kept in a dog crate with their litter and food and water and be on medication at the same time for a period of time until they are retrained to use their litter.
Of course, discuss all this with your veterinarian. Best of luck. I thoroughly admire your devotion. Also, there are many other pages on this site about this problem.