My Bengal boy had his first bout of FLUTD, (Interstitial Cystitis), three years ago. He tends to be hyper, and when I took him to my vet, his urine pH was a 9. A reading of 6.2 is normal, so his was very high. Stress puts the urine pH up, which can contribute to crystal formation and IC.
After a few bouts and trips to both Emergency and my regular vet, several syringes of Buprenorphine for pain, and some Phenoxybenzamine (does the same as Prazosin), my vet decided to give Bela an ongoing prescription for Amitriptyline. It is a tricyclic antidepressant, but it's the specialist's drug of choice for FLUTD in cats for 3 reasons:
1. It is calmative, and keeps his pH down
2. It is analgesic, so it remedies the pain associated with FLUTD
3. It is anti-inflammatory, so it addresses inflamed bladder walls associated with IC/ FLUTD
I keep Phenoxybenzamine on hand for if he exhibits any discomfort and I think his urethral muscles need relaxing. Prazosin is supposed to work into the system faster, though. Bela does not need a relaxer much any more.
I give Bela Cosequin twice per day, sprinkled on his wet food.
At the time of his troubles, I switched him from a grain-free diet, to Urinary SO. I cringed, too. It supposedly dissolves crystals, it acidifies the system/urine to lower the urinary pH, and I figure it is the lesser of two evils. I do not want to see my boy suffer, so I am following the vet's recommendations. It has been three years now, and he seems fine, but if we get off course in the least little way, he starts to have a bout, so ... not much choice. You will all live through it. I've known of cats to eat junky food (I worked in pet food) and they lived to be 23 years old. I saw that over and over, so I wouldn't lose sleep over having to feed a vet diet. One thing I do do, is .. I mix in some Wellness Chicken or Wellness Turkey, in with his prescription food. These two have a good low Ash content in the GA, and they don't seem to throw him into a bout, so we have had good luck adding some better food in with his prescription.
Good luck, and hope you can keep this under control. Water fountains encourage drinking and that is also a good thing, besides slurries.