My cat had urinary tract blockage. Unblocked, was fine, but the vet prescribed 5mg of Phenoxybenzamine 2X a day. Cat got weak, rear legs collapse, won't eat etc. Stopped giving it to him 3 days ago. Drinks water, & I force feed somewhat. No bowel movement. Will this get out of his system. Any info. appreciated. Thanks ## It really sounds like you should take him back to the vet, that sounds more like Kidney failure than anything from the med. If you stopped giving it to him 3 days ago, that is already out of his system, but if you are having to forcefeed him, then something is wrong, go back to the vet NOW!