A selective benzothiophene estrogen receptor modulator (SERM). Raloxifene binds to estrogen receptors (ER) as a mixed estrogen agonist/antagonist; it displays both an ER-alpha-selective partial agonist/antagonist effect and a pure ER-beta-selective antagonist effect. This agent functions as an estrogen agonist in some tissues (bones, lipid metabolism) and as an estrogen antagonist in others (endometrium and breasts), with the potential for producing some of estrogen's beneficial effects without producing its adverse effects. (NCI04)

A selective estrogen receptor modulator; has both agonist and antagonist estrogen action.

The active ingredient in a drug used to reduce the risk of invasive breast cancer in postmenopausal women who are at high risk of the disease or who have osteoporosis. It is also used to prevent and treat osteoporosis in postmenopausal women. It is also being studied in the prevention of breast cancer in certain premenopausal women and in the prevention and treatment of other conditions. Raloxifene blocks the effects of the hormone estrogen in the breast and increases the amount of calcium in bone. It is a type of selective estrogen receptor modulator (SERM).