Formestane

Drugbox
IUPAC_name = (8"R",9"S",10"R",13"S",14"S")-4-hydroxy-10,13-dimethyl-
2,6,7,8,9,11,12,14,15,16-decahydro-1"H"-
cyclopenta [a] phenanthrene-3,17-dione


CAS_number=566-48-3
ATC_prefix=L02
ATC_suffix=BG02
ATC_supplemental=
PubChem=11273
DrugBank=
C = 19 | H = 26 | O = 3
molecular_weight = 302.408 g/mol
bioavailability=
metabolism =
elimination_half-life=
excretion =
pregnancy_category =
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Formestane belongs to a class of drugs known as aromatase inhibitors. It is used in the treatment of estrogen-receptor positive breast cancer in post-menopausal women. It is available as an intramuscular depot injection (Lentaron).

Formestane is often used to suppress estrogen production from anabolic steroids or prohormones. It also acts as a prohormone to 4-hydroxytestosterone, an active steroid which displays weak androgenic activity in addition to acting as a mild aromatase inhibitor.

Formestane has poor oral bioavailability and as such is no longer popular as many orally available aromatase inhibitors have been developed.