I took my cat with recurring UTIs (neurological issues) to a teaching vet hospital and they prescribed methenamine hippurate. They were pretty convinced it would help, but it gave her awful GI symptoms. I'd love a non antibiotic preventative for her even if it's daily, that doesn't cause those issues. It was too much, so I had to take her off of it. I'm not sure if people get those side effects but I hope not (extreme nausea/inappetance and really bad diarhhea).