Medical Condition:
Selective Estrogen Receptor Modulator
A structurally diverse group of compounds distinguished from ESTROGENS by their ability to bind and activate the estrogen receptor, but act as either an estrogen agonist or antagonist depending on the tissue type and hormonal milieu. They are classified as either first generation because they demonstrate estrogen agonist properties in the ENDOMETRIUM or second generation based on their patterns of tissue specificity. (Horm Res 1997;48:155-63)