Article: Tamoxifen

Tamoxifen
Systematic (IUPAC) name
(Z)-2-[4-(1,2-diphenylbut-1-enyl)phenoxy]-N,N-dimethyl-ethanamine
Identifiers
CAS number	10540-29-1
ATC code	L02BA01
PubChem	5376
DrugBank	APRD00123
Chemical data
Formula	C26H29N
Mol. weight	371.515 g/mol 563.638 g/mol (citrate salt)
Pharmacokinetic data
Bioavailability	?
Metabolism	Hepatic (CYP3A4, 2C9 and 2D6)
Half life	5-7 days
Excretion	Fecal
Therapeutic considerations
Pregnancy cat.	B3 (Au) D (US)
Legal status	POM(UK) ℞-only(US)
Routes	Oral

Tamoxifen is an oral selective estrogen receptor modulator which is used in breast cancer treatment, and is currently the world's largest selling breast cancer treatment. It is used for the treatment of early and advanced breast cancer in pre- and post-menopausal women. It is also approved by the Food and Drug Administration (FDA) for the reduction of the incidence of breast cancer in women at high risk of developing the disease. It has been further approved for the reduction of contralateral (in the opposite breast) breast cancer.

Tamoxifen was invented by ICI Pharmaceuticals (now AstraZeneca) and is sold under the brand names Nolvadex, Istubal, and Valodex. It is also available as a generic drug in a number of countries. In the United States and other countries, Tamoxifen was almost always referred to by its generic name even before its patents expired.

A rare condition occasionally treated with tamoxifen is retroperitoneal fibrosis.

Tamoxifen is sometimes used to treat gynecomastia in men. Tamoxifen is also used by bodybuilders in a steroid cycle to try and prevent or reduce drug-induced gynecomastia caused by steroids that are used in the same cycle.

Tamoxifen is also used to treat infertility in women with anovulatory disorders. A dose of 10-40 mg per day is administered in days 3-7 of a woman's cycle.

On April 17, 2006, it was announced that raloxifene is equally effective in reducing the incidence of breast cancer, but caused fewer side effects. [1] [2]

4-hydroxytamoxifen

4-hydroxytamoxifen is a form of the drug tamoxifen that is made by the body after taking tamoxifen. It can also be made in the laboratory, and may help decrease breast density. A topical form of 4-hydroxytamoxifen is being studied in breast cancer screening.