Objective: Selective estrogen receptor modulators (SERMs) include a relatively large number of compounds, each with different profiles of estrogenic/antiestrogenic actions on the genital tract. The aim of this review was to systematically evaluate all the available data from randomized, controlled studies on the effects of these compounds on pelvic organ prolapse and urinary incontinence.
Methods: Literature searches were performed using three computerized databases to identify the result of all randomized, controlled trials performed with SERMs having any effects on pelvic floor as an outcome. A manual search was performed on all related articles.
Results: We have identified only one randomized, placebo-controlled trial specifically designed to assess the effect of raloxifene and tamoxifen on the urogenital tract. Most of the data on genitourinary effects of various compounds derive from either questionnaires or adverse events reported during phase III clinical trials. Both tamoxifen and raloxifene appear to increase the incidence of pelvic floor prolapse in one trial, although this was not apparent from the licensing studies data for either of the drugs. Raloxifene does not appear to increase the incidence of urinary incontinence. Levormeloxifene and idoxifene, on the contrary, were noted to increase uterine prolapse and incontinence during phase III trials that prematurely terminated. No data are available on the genitourinary effect of toremifene and on the newer SERMs currently undergoing phase III trials: basedoxifene, lasofoxifene, and arzoxifene.
Conclusion: Contrary to their effects in bone, SERMs do not have a class-specific effect on the genitourinary tract. In fact, compounds that are more estrogenic on the uterus such as levormeloxifene and idoxifene also increase the risk of prolapse and incontinence. SERMs can adversely affect the pelvic floor and incontinence but data from urodynamic studies are not yet available. Data on prolapse are contradictory. Given the increased incidence of prolapse and incontinence observed in several licensing trials, more focused research on the effect of these molecules on pelvic floor function is needed.