Randomized study of single-dose, three-day, and seven-day treatment of cystitis in women.

We evaluated the following five treatment regimens for acute cystitis in nonpregnant women: cefadroxil, 1,000 mg single-dose; cefadroxil, 500 mg twice a day for three days; cefadroxil, 500 mg twice a day for seven days; trimethoprim-sulfamethoxazole (TMP-SMZ), 320-1,600 mg single-dose, and TMP-SMZ, 160-800 mg twice a day for three days. At four weeks after the end of treatment, 25%, 58%, 70%, 65%, and 88% of patients, respectively, remained cured of infection. The results indicated that three-day treatment (1) might improve cure rates (over single-dose), (2) would reduce incidence of relapse (vs. single-dose), and (3) may be as curative as seven-day treatment. The results of the antibody-coated bacteria test did not predict treatment failure or relapse.