Testolactone

Testolactone

Clinical data
AHFS/Drugs.com	Consumer Drug Information
Pregnancy category	US: C (Risk not ruled out)
Routes of administration	Oral
ATC code	none
Pharmacokinetic data
Protein binding	~85%
Metabolism	Hepatic
Excretion	Renal
Identifiers
IUPAC name (4aS,4bR,10aR,10bS,12aS)-10a,12a-Dimethyl-3,4,4a,5,6,10a,10b,11,12,12a-decahydro-2H-naphtho[2,1-f]chromene-2,8(4bH)-dione
CAS Number	968-93-4 Y
PubChem CID	13769
IUPHAR/BPS	7303
DrugBank	DB00894 Y
ChemSpider	13172 N
UNII	6J9BLA949Q
KEGG	D00153 Y
ChEBI	CHEBI:9460 N
ChEMBL	CHEMBL1571 N
ECHA InfoCard	100.012.304
Chemical and physical data
Formula	C19H24O3
Molar mass	300.39 g/mol
3D model (Jmol)	Interactive image
SMILES CC12CCC3C(C1CCC(=O)O2)CCC4=CC(=O)C=CC34C
NY (what is this?)

Testolactone (INN, USAN) (brand name Teslac) is a non-selective, irreversible, steroidal aromatase inhibitor used as an antineoplastic drug to treat advanced-stage breast cancer. The drug was discontinued in 2008 and is no longer available for medical use.

This drug is mainly used for treating various types of breast cancer in women who have been through menopause or whose ovaries no longer function. It works by blocking the production of estrogen, which helps prevent the growth of breast cancers that are activated by estrogen. It may also prevent tumor cells from being activated by other hormones. It also has been used to postpone precocious puberty because of its ability to block estrogen production.

The most common side effects include:

The principal action of testolactone is reported to be inhibition of aromatase activity and the reduction in estrogen synthesis that follows. Androstenedione, a 19-carbon steroid hormone produced in the adrenal glands and the gonads, is where estrone synthesis originates and is the source of estrogen in postmenopausal women. In vitro studies report that the aromatase inhibition may be noncompetitive and irreversible, and could possibly account for the persistence of this drug's effect on estrogen synthesis after drug withdrawal.

In addition to its activity as an aromatase inhibitor, testolactone also reportedly possesses some anabolic activity and weak androgenic activity via binding to and activation of the androgen receptor. However, androgenic side effects such as hirsutism, acne, and voice changes have been reported in no women in clinical trials.