Efficacy of single-dose versus seven-day trimethoprim treatment of cystitis in women: a randomized double-blind study.

Single-dose trimethoprim treatment of cystitis was compared with 7-day treatment in a randomized double-blind study in primary health care. Consecutive female patients (613) with symptoms of lower urinary tract infection (UTI) and positive bacteriuria screening tests were enrolled. In 502 cases UTI was confirmed by urine culture. Follow-up was performed twice, after 2-3 and 5-6 weeks. Short-term efficacy could be evaluated in 425 cases and accumulated efficacy in 344. Short-term efficacy was 82% for single-dose and 94% for 7-day treatment (P less than .001). Accumulated efficacy was 71% for single-dose and 87% for 7-day therapy (P less than .001). Fewer adverse reactions were noted with single-dose therapy (not significant). The cure rate for UTI caused by P-fimbriated Escherichia coli was not different from that of other E. coli infections. Infections with Staphylococcus saprophyticus showed a lower cure rate than E. coli infections with the single-dose regimen (P less than .05 for short-term efficacy).