Treatment of lower urinary tract infections with single-dose trimethoprim-sulfamethoxazole.

Two hundred three women from a primary care medical practice with symptoms of lower urinary tract infection and positive urine cultures were treated with trimethoprim-sulfamethoxazole. One hundred eleven women received a single dose and 92 were treated for ten days. Cure rates were 87 percent and 89 percent, respectively, one week after therapy. A narrow 95 percent confidence interval for the difference between the two cure rates (.02 +/- .09) suggests the treatments are equally effective. Patients were followed by chart audit and a self-reporting questionnaire. No difference in recurrence rates was found between the two groups six months after therapy. Single-dose trimethoprim-sulfamethoxazole is as effective as ten-day treatment in women with symptoms suggestive of lower urinary tract infection and has no greater relapse rate.