Effective prophylaxis of recurrent urinary tract infections in premenopausal women by postcoital administration of cephalexin.

A total of 31 sexually active premenopausal women, prone to have recurrent urinary tract infections but who otherwise were healthy, underwent postcoital prophylaxis consisting of a single oral dose of 250 mg. cephalexin. While 127 urinary tract infections occurred in these patients during a mean of 6 months before treatment, only 1 occurred during a mean of 12 months after postcoital cephalexin prophylaxis. This difference was statistically highly significant. Each of these patients ingested approximately 120 cephalexin tablets per year of postcoital prophylaxis. Postcoital oral cephalexin prophylaxis is highly effective in the prevention of recurrent urinary tract infection in the nonpregnant as well as pregnant premenopausal women because of easy compliance, the high urine concentration achieved and the minimal induction of resistance to cephalexin in the introital gram-negative bacterial flora. Postcoital cephalexin prophylaxis achieves identical results to daily cephalexin prophylaxis but uses only a third of the tablets required in the daily regimens. Finally, cephalexin represents an additional valuable antibacterial drug in postcoital prophylaxis along with cotrimoxazole, nitrofurantoin and cinoxacin.