Purpose: We evaluated and compared the efficacy of post-intercourse and daily oral ciprofloxacin prophylaxis against recurrent lower urinary tract infections in 135 sexually active premenopausal women.

Materials and methods: Post-intercourse (group 1, 70 patients) and daily (group 2, 65 patients) prophylactic regimens of 125 mg. ciprofloxacin were started following a curative, conventional treatment of the initial acute urinary tract infection. Prophylaxis was maintained for 12 months and during this period patients were followed clinically and bacteriologically with urine and introital samples. Patients were subsequently followed for an additional year after the end of preventive treatment.

Results: While 3.67 urinary tract infections per patient in group 1 and 3.74 in group 2 occurred during an identical mean time of 12.2 months before start of the corresponding prophylactic regimen, only 0.043 infection per patient in group 1 and 0.031 in group 2 developed during prophylaxis (p < 0.0001). Before prophylaxis 86% of the vaginal vestibule cultures yielded gram-negative Enterobacteriaceae, equally distributed between both treatment arms, compared to 5.6% and 2.5% during postcoital and daily prophylaxis, respectively. The overall improvement in the incidence of the urinary infections per patient and the rate of introital colonization with enteric gram-negative bacteria was maintained after the end of prophylaxis, with a mean incidence of infections of 0.44 per patient (occurring in 34% of the total patient population), while 36% of all women had abnormal introital colonization.

Conclusions: Long-term post-intercourse prophylaxis with ciprofloxacin proved to be equally effective as daily prophylaxis, and the major advantage of the former therapy was use of only a third of the amount of drug consumed in daily prophylaxis.