Authors: Raz R, Stamm WE.
Publication Year: 1993
Citation: N Engl J Med 1993;329(11):753-6.
This randomized, double blind, placebo-controlled trial looked at the incidence of urinary tract infections (UTI) in 93 postmenopausal women using 0.5 mg estriol vaginal cream once nightly for two weeks followed by twice weekly application or placebo. Results showed significantly lower UTI rates in treatment group (0.5 infections per patient-year vs. 5.9 for placebo group). The mean vaginal pH fell from 5.5+-0.7 to 3.6+-1.0 for treatment group and 5.8+-1/2 to 6.1+-2.0 in placebo group and there was an increase in vaginal colonization with lactobacilli in the treatment group. Authors recommend use of topical vaginal estriol in preventive treatment of women with frequent UTI as possible replacement for long-term use of nitrofurantoin, co-trioxazole, trimethoprim, cehpalexin or fluoroquinolones.