Levonorgestrel

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Levonorgestrel
Systematic (IUPAC) name
13-ethyl-17-ethynyl-17-hydroxy- 1,2,6,7,8,9,10,11,12,13,14,15,16, 17- tetradecahydrocyclopenta[a] phenanthren-3-one
Identifiers
CAS number	17489-40-6
ATC code	G03AC03
PubChem	13109
DrugBank	APRD00754
Chemical data
Formula	C₂₁H₂₈O₂
Mol. mass	312.446 g/mol
Pharmacokinetic data
Bioavailability	~100%
Protein binding	55%
Metabolism	Hepatic
Half life	?
Excretion	Renal: 45%; Fecal:32%
Therapeutic considerations
Pregnancy cat.	?
Legal status
Routes	Implant; insert (extended-release); oral

Levonorgestrel (or l-norgestrel or D-norgestrel) is a synthetic progestagen, normally used as an active ingredient in hormonal contraceptives.

1 Chemistry
2 Usage
3 References
4 External links

[edit] Chemistry

Chemically, it is a hormonally active levorotatory enantiomer of the racemic mixture norgestrel. It is a gonane progestin derived from 19-nortestosterone.^[1]

Its in vitro relative binding affinities at human steroid hormone receptors are: 323% that of progesterone at the progesterone receptor, 58% that of testosterone at the androgen receptor, 17% that of aldosterone at the mineralocorticoid receptor, 7.5% that of cortisol at the glucocorticoid receptor, and <0.02% that of estradiol at the estrogen receptor.^[2]

[edit] Usage

Main article: birth control

[edit] Oral contraceptives

At low doses, levonorgestrel is used in monophasic and triphasic formulations of combined oral contraceptive pills, with available monophasic doses ranging from 100-250 µg, and triphasic doses of 50 µg/75 µg/125 µg.

At very low daily dose of 30 µg, levonorgestrel is used in some progestogen only pill formulations.

[edit] Emergency contraception

Levonorgestrel is used in emergency contraception pills, both in a combined regimen which includes estrogen, and as a levonorgestrel-only method. For the latter, a single dose of 1500 ug within 3 days is almost 100% effectve. There are many names for levonorgestrel-only emergency contraception products, including Plan B, Levonelle One Step, and Postinor-2.

[edit] IUD

Levonorgestrel is the active ingredient in Mirena.

[edit] Contraceptive implants

Levonorgestrel is the active ingredient in Norplant and Jadelle.

[edit] References

^ Edgren RA, Stanczyk FZ (1999). "Nomenclature of the gonane progestins". Contraception 60 (6): 313. PMID 10715364.
^ Sitruk-Ware R (2006). "New progestagens for contraceptive use". Hum Reprod Update 12 (2): 169-78. PMID 16291771.

[edit] External links

Levonelle manufacturer's product information from Schering
Monograph for levonorgestrel - Uk Medicines Information

v • d • e Sex hormones and related agents (primarily G03, also L02, H01C) - human endogenous in CAPS
Progestogens: (receptor)	PROGESTERONE, Desogestrel, Drospirenone, Dydrogesterone, Ethisterone, Etonogestrel, Ethynodiol diacetate, Gestodene, Gestonorone, Levonorgestrel, Lynestrenol, Medroxyprogesterone, Megestrol, Norelgestromin, Norethisterone, Norethynodrel, Norgestimate, Norgestrel, Norgestrienone, Tibolone Antiprogestogen: Mifepristone
Androgens: (receptor)	TESTOSTERONE, Androstanolone, Fluoxymesterone, Mesterolone, Methyltestosterone, (see also anabolic steroids) Antiandrogens: Bicalutamide, Cyproterone, Flutamide, Nilutamide, Spironolactone
Estrogens: (receptor)	ESTRADIOL, ESTRIOL, ESTRONE, Chlorotrianisene, Dienestrol, Diethylstilbestrol, Ethinylestradiol, Fosfestrol, Mestranol, Polyestradiol phosphate Selective estrogen receptor modulator: Bazedoxifene, Clomifene, Fulvestrant, Raloxifene, Tamoxifen, Toremifene Aromatase inhibitor: Aminogluthetimide, Anastrozole, Exemestane, Formestane, Letrozole, Vorozole
Gonadotropins: (FSHR/LHCGR)	ovulation stim.:Clomifene, Urofollitropin Antigonadotropins: Danazol, Gestrinone
GnRH: (receptor)	agonist: Buserelin, Goserelin, Histrelin, Leuprorelin, Nafarelin, Triptorelin antagonist: Abarelix, Cetrorelix, Ganirelix