Selective estrogen receptor modulators: a new category of compounds to extend postmenopausal women's health

Selective estrogen receptor modulators (SERMs) are a new category of therapeutic agents, which bind with high affinity to estrogen receptors and mimic the effect of estrogens in some tissues but act as estrogen antagonists in others. Tamoxifen, a triphenylethylene derivative, was the first clinically available SERM. It is a potent anti-estrogen in the breast, and its use in breast cancer patients has made it the most widely prescribed antineoplastic drug worldwide. It has estrogen-like activity on bone metabolism, as well as cholesterol reduction. However, its ability to produce proliferation, and polyp formation, and even carcinomas, in the endometrium is well known. A new SERM, raloxifene, a benzothiopene derivative, has a clinical profile similar to tamoxifen's. However, preclinical as well as clinical studies reveal that unlike tamoxifen it is a pure anti-estrogen in the uterus. It has recently been FDA approved for prevention of osteoporosis in postmenopausal women. This report reviews pertinent preclinical and currently available clinical studies about this new SERM and discusses clinical applicability.