Drug Name	Mechanism of action	Chemical formula	History	Applications
Tamoxifen	It is metabolized in the liver by the cytochrome p450 isoform CYP2D6 and CYP3A4 into active metabolites such as 4-hydroxytamoxifen and N-desmethyl-4-hydroxytamoxifen^.which have 30 - 100 times more affinity with the estrogen receptor than tamoxifen itself.	C₂₆H₂₉NO	Discover in 1967 most important drug need for basic health system.	Tamoxifen is currently used for the treatment of both early and advanced ER+ (estrogen receptor positive) breast cancer in pre- and post-menopausal women.
Fulvestrant	When fulvestrant binds to estrogen receptor monomers it inhibits receptor dimerization, activating function 1 (AF1) and AF2 are rendered inactive, translocation of receptor to the nucleus is reduced, and degradation of the estrogen receptor is accelerated.	C₃₂H₄₇F₅O₃S	Fulvestrant is another antiestrogen, and is the only pure antiestrogen, or silent 4 KB (380 words)-16:12, 21 January 2016	It is indicated for the treatment of hormone receptor positive metastatic breast cancer in postmenopausal women.
Aromatase inhibitors	Aromatase inhibitors work by inhibiting the action of the enzyme aromatase, which converts androgens into estrogens by a process called aromatization.	C17-H11-N5	The commercial names and year of approval in the United States are: letrozole (Femara, 1995).	Used in the treatment of breast cancer and ovarian cancer in postmenopa-usal women and gynecomastia in men.
Raloxifene	Enter the nucleus of the target organ cells in order to bind there to a series of unoccupied, inactive proteins, called ER.	C₂₈H₂₇NO₄S	Tumor registry and membership files identify women diagnosed with breast cancer after 1994 who were health plan members in 1998 or later, when raloxifene became available	Raloxifene is indicated for the treatment and prevention of osteoporosis in postmenopausal women.