UTI. Already tried Clavimox & Trimethoprim. He still is not well.

I am new to this site and so glad to find such a great place to talk to other cat lovers.
I am hoping someone can help my sweet male cat. Since Aug he has periodically wandered the house from window to window meowing and marking the walls. To my shame I at first thought he was just upset about the feral cats, from surrounding farms, that I have had neutered and am feeding. He had a UTI according to the Vet. I brought in a sample, not sterile, but contained blood and high white blood cells. Started him on amoxicillin which didn't help. The Vet then gave him Clavimox. He improved and started playing again. I thought at the time that two weeks might not be long enough, as he just improved towards the end of week two. Vet said it was long enough but to look at sample again in one month.
He got worse again and same results in second sample. Next tried Cefa-Drops which he immediately threw up. He had threw up two doses of Clavimox also. Next antibiotic tried was a sulfa drug Trimethoprim and pain medication, Bupro something. He seemed to tolerate it better but was very tired. I mentioned this to the Vet but he wasn't concerned. Nine days in and he was lethargic and running a fever. I looked up side effects and people have had this type of reaction. I called the Vet back and they said take him off the antibiotic, which I had already done the night before. It took four days for the fever to stop, Vet had me give him a baby aspirin every 48 hours to lower fever. I had to bring him back to the Vet during that time for fluids and to get blood work done. He was one sick kitty.
Blood tests on kidneys and liver function okay. No on HIV and Leukemia. CBC okay except for platelets which are low. He is feeling better now three weeks after fever but still has episodes of pain and marking. I have had him on cooked chicken with a vitamin premix for cats for two months now - he ate canned cat food before and small amounts intermittently of dry no grain. I add as much water to the food as he will eat. The Vet wants to use Baytril next, I said no way after reading possible side effects like blindness. I read the post on the kitty who has lost sight from too much Baytril- horribly tragically sad.
I am at a loss as to how to help my cat. He is extremely sensitive to foods and medications. He had a hard time with anesthesia at 5 1/2 months of age when he was neutered. I am looking into possible use of Butterbur, but at what doseage and is it safe for cats? I dont really trust the Vet to know how to help him and I am still paying off the blood work. I can't afford to take him three hours away to the nearest specialist as the Vet recommended, as much as I wish I could. Does anyone have any advice? I really can't bear to lose him or see him suffer. Would Nitrofurantoin (Macrobid) be safe for him to take? Could it be Cystitis? Thank you for reading this thread.

I would get a second opinion.  Has the urine been cultured and examined for the presence of crystals?  Is he urinating at all?  Have you changed his diet to a one for kitties with UTIs?

I agree with getting the culture done to check for crystals. I had a kitten who had what we thought was a UTI and after 2 full weeks of antibiotics he had more blood in his urine than before. A culture was sent off and it came back that he was producing very high amounts of crystals. A few weeks on the urinary prescription diet and he was much better.

Thank you for your response to my plea for help. He has been tested for the presence of crystals and stones. No ultra sound but X-ray showed inflamed bladder walls, no stones. Three urine cultures over the last 4 months have showed no crystals. I am feeding him cooked chicken breast with vitamin powder premix and lots of broth. He hasn't had any blockages.
Two years ago he ate some Christmas ribbon, the kind with the sharp edges. The Vet gave him hydrogen peroxide to get him to throw it up. He didn't for hours. When he did throw up he threw up some blood with the ribbon. I can't help but wonder if the hydrogen peroxide messed him up. He always was sensitive to lots of cat food, but became very intolerant after. Plain chicken I cook or turkey is what he doesn't throw up, hasn't in several months. He also tried to get outside all the time to eat grass. Then he wanted back inside and would throw up. I planted oat grass which he loves and does well on, that solved the grass problem, mostly.

I've see you feed him cooked chicken with a vitamin premix for cats

Does the vitamin premix include Taurine?  Quite often they are made for people who choose to prepare a raw diet for their cats (see our raw and home cooked feeding forum), and may not be appropriate for cooked chicken as cooking removes the Taurine. 

It does contain taurine. He also eats a raw egg yolk everyday.

If you are going to try a new antibiotic you can enquire about Veraflox similar to Baytril but is safer from an ocular perspective 

http://www.researchgate.net/publica...terial_Lower_Urinary_Tract_Infections_in_Cats 

Thank you very much. I will take this information to my vet. The only antibiotic he talked about was Baytril. He is a farm vet and its an hour away to the next vet clinic. I am happy to hear about Veraflox being safer and effective in the article you referenced.