I had uti/ecoli.doc gave me cipro.that gave me vertigo.switched to zpack. 6 days later doc says he made a mistake & put me on bactrim. i didnt take it until urologist advised me to take it. i took it & now uro told me stop and take amoxicillin. why?

Hard to guess: Usually when there is a urine culture, the lab can tell which antibiotics should work, and which antibiotics might not work (lab looks for the bacteria's resistance to a panel of 7-10 different antibiotics). The choice of medication also depends on a patient's past history of similar infections, of antibiotic usage, and of other factors unique to that patient's case. Details make the difference.