I haven't used prazosin, but whether or not you should wean your kitty off it is probably something you should ask the vet. I'd imagine, though, that the vet would have mentioned it if it's a drug that needs to be stepped down.
Buprex is buprenorphine? Just curious about how you'll wean kitty off it. Will you space out the doses? I gave it to my kitty until I had to let her go so never had the issue, but it was given in pre-filled syringes, so I don't know how I would have weaned her off.
Is the Adequan also for FLUTD or for arthritis?
Hope your little guy is feeling better soon!