Prescribed sulfamethoxazole tmp DS every 12 hours, began treatment Wednesday PM. No urinalysis, no relief from symptoms! Symptoms tonight GREATLY exacerbated, blood in urine. It s Saturday! I have a prescription already filled with 10 levofloxacin 250 mg and I just now stopped the sulfamethoxazole and took a levofloxacin. Should I continue with the course of levo to see if symptoms are relieved, or should I visit Urgent Care tomorrow to give urine sample? Note: never prescribed Bactrim/sulfamethoxazole for UTI before now, always had previous success with nitrofurantoin. Could nitrofurantoin be better than levo right now? Desperate for relief.