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 797-63-7
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 36 ± 13 hours
Excretion Renal: 45%; Fecal:32%
Therapeutic considerations
Pregnancy cat.

X
Legal status
Routes Implant; insert (extended-release); oral

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

Contents

[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 contraceptive pills (ECPs), both in a combined Yuzpe regimen which includes estrogen, and as a levonorgestrel-only method. The levonorgestrel-only method uses levonorgestrel 1500 μg (as a single dose or as two 750 μg doses 12 hours apart) taken within 3 days of unprotected sex. There are many brand names of levonorgestrel-only ECPs, including: Escapelle, Plan B, Levonelle, NorLevo, Postinor-2, and 72-HOURS.[3]

[edit] IUD

Levonorgestrel is the active ingredient in Mirena.

[edit] Contraceptive implants

Levonorgestrel is the active ingredient in Norplant and Jadelle.

[edit] References

  1. ^ Edgren RA, Stanczyk FZ (1999). "Nomenclature of the gonane progestins". Contraception 60 (6): 313. doi:10.1016/S0010-7824(99)00101-8. PMID 10715364. 
  2. ^ Sitruk-Ware R (2006). "New progestagens for contraceptive use". Hum Reprod Update 12 (2): 169-78. PMID 16291771. 
  3. ^ Trussell, James; Cleland, Kelly (2007-04-10). Emergency Contraceptive Pills Worldwide. Princeton University. Retrieved on 2007-05-28.

[edit] External links

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Sex hormones and related agents (primarily G03, also L02, H01C) - human endogenous in CAPS
Progestogens:
(receptor)
Androgens:
(receptor)
Estrogens:
(receptor)
Gonadotropins:
(FSHR/LHCGR)
GnRH:
(receptor)
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