To assess the efficacy of nitrofurantoin vs trimethoprim-sulfamethoxazole , 338 women aged 18 to 45 years with acute uncomplicated cystitis were randomized to open-label treatment with either trimethoprim-sulfamethoxazole , 1 double-strength tablet twice daily for 3 days , or nitrofurantoin , 100 mg twice daily for 5 days .
