Systematic (IUPAC) name
Clinical data
AHFS/ International Drug Names
MedlinePlus a604034
Pregnancy cat.  ?
Legal status  ?
Pharmacokinetic data
Bioavailability 64%
Protein binding >95%
Half-life 7 hours
CAS number 68-22-4 YesY
ATC code G03AC01 G03DC02
PubChem CID 6230
DrugBank APRD00679
ChemSpider 5994 YesY
UNII T18F433X4S YesY
KEGG D00182 YesY
Chemical data
Formula C20H26O2 
Mol. mass 298.419 g/mol
SMILES eMolecules & PubChem
 N(what is this?)  (verify)

Norethisterone (or norethindrone) (or 19-nor-17α-ethynyltestosterone) is a molecule used in some combined oral contraceptive pills, progestogen only pills and is also available as a stand-alone drug. It is a progestogen and can be used to treat premenstrual syndrome, painful periods, abnormal heavy bleeding, irregular periods, menopausal syndrome (in combination with oestrogen), or to postpone a period. It is also commonly used to help prevent uterine hemorrhage in complicated non-surgical or pre-surgical gynecologic cases. Norethindrone was the first orally highly active progestin to be synthesized. It was synthesized for the first time by chemists Luis Miramontes, Carl Djerassi, and George Rosenkranz at Syntex in Mexico City in 1951.[1] It was the progestin used in one of the first two oral contraceptives. It is often used as the related ester, norethisterone acetate.


Norethisterone synth.png


  1. ^ Djerassi, C.; Miramontes, L.; Rosenkranz, G.; Sondheimer, Franz (1954). "Steroids. LIV. Synthesis of 19-Nor-17α-ethynyltestosterone and 19-Nor-17α-methyltestosterone". J. Am. Chem. Soc. 76 (16): 4092–94. doi:10.1021/ja01645a010.