A total of 77 sexually active premenopausal women, susceptible to recurrent urinary tract infections (UTI) but otherwise healthy, were subjected to postcoital prophylaxis consisting of a single oral dose of either cotrimoxazole (80 mg trimethoprim+400 mg sulfamethoxazole), 50 mg nitrofurantoin macrocrystals, 500 mg nalidixic acid, 250 mg cinoxacin or 250 mg cephalexin. Postcoital prophylaxis reduced the incidence of recurrent UTI from 5-8 UTI per patient/year prior to prophylaxis, to a mere 0.03 UTI per patient/ year following prophylaxis. The differences in the incidence of UTI prior to and following institution of postcoital prophylaxis were statistically highly significant. A mean of 106–120 antibacterial tablets per patient were administered per year.
Postcoital prophylaxis of recurrent UTI in premenopausal women is highly effective because of easy compliance, the high urinary concentration achieved and the minimal induction of resistance in the introital Gram-negative bacterial flora, irrespective of the length of time this prophylaxis is used. Furthermore, postcoital prophylaxis is significantly more effective than daily, as it achieves the same effect but requires only one third or fewer of the antibacterial tablets used in daily prophylaxis. At present, postcoital prophylaxis with cotrimoxazole, nitrofurantoin macrocrystals or cephalexin is recommended.
Keywords Postcoital prophylaxis - Premenopausal women - Recurrent urinary tract infections