Levonorgestrel

Levonorgestrel
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
Clinical data
Trade names Norplant
MedlinePlus a610021
Pregnancy cat. X
Legal status  ?
Routes Implant; insert (extended-release); oral
Pharmacokinetic data
Bioavailability ~100%
Protein binding 55%
Metabolism Hepatic via CYP3A4
Half-life 36 ± 13 hours
Excretion Renal: 45%; Fecal:32%
Identifiers
CAS number 797-63-7 YesY
ATC code G03AC03 G03AD01
PubChem CID 13109
DrugBank APRD00754
ChemSpider 12560 YesY
UNII 5W7SIA7YZW N
KEGG D00950 N
ChEBI CHEBI:6443 N
ChEMBL CHEMBL1389 N
Chemical data
Formula C21H28O2 
Mol. mass 312.446 g/mol
 N(what is this?)  (verify)

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

Contents

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]

If taken concommitantly with drugs that induce the CYP3A4 cytochrome liver enzyme, the levonorgestrel will be metabolized faster and have lower efficacy.(Citation?) A larger dose is required to maintain the high level of efficacy expected of a birth control medication.

Usage

Oral contraception

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.

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, with one study indicating that beginning as late as 120 hours (5 days) after intercourse could be effective. There are many brand names of levonorgestrel-only ECPs, including: Escapelle, Plan B, Levonelle, NorLevo, Postinor-2, i-pill, "Next Choice" and 72-HOURS.[3]

Intrauterine system

Levonorgestrel is the active ingredient in the Mirena intrauterine system.

Contraceptive implants

Levonorgestrel is the active ingredient in Norplant and Jadelle.

Side effects

Possible side effects of levonorgestrel include nausea, vomiting, stomach pain, dizziness, breast tenderness, tiredness and weakness, headache, menstrual changes, and diarrhea.[4]

It decreases total and free testosterone, androstenedione, dehydroepiandrosterone sulfate (DHEAS), dihydrotestosterone (DHT) and sex hormone–binding globulin (SHBG), but has no effect on sexual function or markers of androgen bioactivity.[5]

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. doi:10.1093/humupd/dmi046. PMID 16291771. 
  3. ^ Trussell, James; Cleland, Kelly (2007-04-10). "Emergency Contraceptive Pills Worldwide". Princeton University. http://ec.princeton.edu/questions/dedicated.html. Retrieved 2007-05-28. 
  4. ^ MedicineNet.com > LEVONORGESTREL - ORAL (lee-voh-nor-JEST-rell) Retrieved on April 3, 2010
  5. ^ Kovalevsky G, Ballagh SA, Stanczyk FZ, Lee J, Cooper J, Archer DF (April 2010). "Levonorgestrel effects on serum androgens, sex hormone-binding globulin levels, hair shaft diameter, and sexual function". Fertil. Steril. 93 (6): 1997–2003. doi:10.1016/j.fertnstert.2008.12.095. PMID 19394598. 

External links


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Look at other dictionaries:

  • Levonorgestrel — Nombre (IUPAC) sistemático …   Wikipedia Español

  • Levonorgestrel — Lévonorgestrel Lévonorgestrel Général Nom IUPA …   Wikipédia en Français

  • Lévonorgestrel — Général Nom IUPAC …   Wikipédia en Français

  • levonorgestrel — /lē vō nör jesˈtrəl/ noun A hormone used in oral contraceptives, esp as an emergency contraceptive taken a few hours after intercourse ORIGIN: The l(a)evorotatory form of the hormone norgestrel …   Useful english dictionary

  • Levonorgestrel — Strukturformel Allgemeines Freiname Levonorgestrel Andere Namen …   Deutsch Wikipedia

  • levonorgestrel — A form of the hormone progesterone that is made in the laboratory and used to prevent pregnancy. It is being studied in the prevention of ovarian and endometrial cancer, and in the treatment of other conditions. Levonorgestrel is a type of oral… …   English dictionary of cancer terms

  • levonorgestrel — noun Etymology: lev + norgestrel, a progestin Date: 1977 the levorotatory form of a synthetic progestin C21H28O2 used especially in oral contraceptives …   New Collegiate Dictionary

  • levonorgestrel — le·vo·nor·ges·trel (lē və nôr jĕsʹtrəl) n. The levorotatory form of norgestrel, used in oral contraceptives and in contraceptives implanted subdermally. In implant form it can prevent pregnancy for up to five years. * * * …   Universalium

  • levonorgestrel — noun A synthetic progestogen used as an active ingredient in some hormonal contraceptives …   Wiktionary

  • levonorgestrel — le·vo·nor·ges·trel .lē və nȯr jes trəl n the levorotatory form of norgestrel used in birth control pills and contraceptive implants see NORPLANT * * * n. a synthetic female sex hormone a progestogen used mainly in oral contraceptive, either in… …   Medical dictionary

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