Title: Etonogestrel
CAS Registry Number: 54048-10-1
CAS Name: (17a)-13-Ethyl-17-hydroxy-11-methylene-18,19-dinorpregn-4-en-20-yn-3-one
Additional Names: 17-ethynyl-17b-hydroxy-18-methyl-11-methyleneestr-4-en-3-one; 3-ketodesogestrel; 3-oxodesogestrel
Manufacturers' Codes: Org-3236
Trademarks: Implanon (Organon)
Molecular Formula: C22H28O2
Molecular Weight: 324.46
Percent Composition: C 81.44%, H 8.70%, O 9.86%
Literature References: Biologically active metabolite of desogestrel, q.v.. Prepn: H. Hofmeister et al., EP 51762; eidem, US 4371529 (1982, 1983 both to Schering AG); H. Gao et al., Steroids 62, 398 (1997). Series of articles on clinical experience: Contraception 58, Suppl. 1, 75S-115S (1998). Clinical safety and efficacy: H. B. Croxatto et al., Hum. Reprod. 14, 976 (1999). Review of clinical studies: J. E. Edwards, A. Moore, Br. J. Fam. Plann. 24, 3-16 (1999).
Properties: mp 199-201°. [a]D +87.6°.
Melting point: mp 199-201°
Optical Rotation: [a]D +87.6°
Therap-Cat: Progestogen; implantable contraceptive.
Keywords: Contraceptive (Implantable); Progestogen.
Etoperidone Etorphine Etoxazole Etozolin Etretinate

Systematic (IUPAC) name
Clinical data
AHFS/ Multum Consumer Information
MedlinePlus a604032
Legal status Prescription Only (S4) (AU) POM (UK) -only (US) Prescription only
Routes Subdermal as slow-release implant
Pharmacokinetic data
Metabolism Hepatic (P450 3A4)
Half-life 25 hours
Excretion Urinary (majority) and fecal
CAS number 54048-10-1 YesY
ATC code G03AC08
PubChem CID 21729469
DrugBank DB00294
ChemSpider 5292944 YesY
KEGG D04104 YesY
ChEBI CHEBI:50777 YesY
Chemical data
Formula C22H28O2 
Mol. mass 324.457 g/mol
 YesY (what is this?)  (verify)

Etonogestrel is a steroidal progestin used in hormonal contraceptives, most notably the subdermal implant Nexplanon and the vaginal ring NuvaRing.

Etonogestrel is the active metabolite of the inactive prodrug desogestrel, one of two third-generation progestins found in some epidemiological studies of combined oral contraceptive pills to be associated with a higher risk of venous thrombosis than combined oral contraceptive pills containing certain second-generation progestins. Because hormones are released continuously from NuvaRing, peak and total estrogen and progestin doses are significantly lower than with combined oral contraceptives, although it is not known whether this lowers the risk of blood clots.