[Rationale for the treatment of postmenopausal women by SERM]

Raloxifene has been developed as a selective estrogen receptor modulator (SERM) that binds to estrogen receptor (ER) and acts as an estrogen agonist in some tissues while acting as an estrogen antagonist in certain tissues. Raloxifene exerts anti-estrogenic actions in the uterus and the mammary gland, whereas it has estrogenic effects on bone and serum lipids. As a result, raloxifene increases bone volume and reduces vertebral fractures without increasing the incidence of uterine cancer. In addition, raloxifene reduces the incidence of breast cancer to nearly a third of those without raloxifene treatment by markedly reducing the development of ER-positive breast cancer. Raloxifene also reduces the risk of cardiovascular events among postmenopausal women with increased cardiovascular risk. From these observations, postmenopausal osteoporotic women without multiple or severe fractures who have risk factors for breast cancer or cardiovascular disorders can be excellent candidates for raloxifene treatment.