Levonorgestrel

Not to be confused with Medication abortion.
Levonorgestrel
Clinical data
Trade namesPlan B, Julie, Mirena, Plan B One-Step, Liletta, others
Other namesLNG; LNG-EC; d-Norgestrel; d(–)-Norgestrel; D-Norgestrel; WY-5104; SH-90999; NSC-744007; 18-Methylnorethisterone; 17α-Ethynyl-18-methyl-19-nortestosterone; 17α-Ethynyl-18-methylestr-4-en-17β-ol-3-one; 13β-Ethyl-17α-hydroxy-18,19-dinorpregn-4-en-20-yn-3-one
AHFS/Drugs.comMonograph
MedlinePlusa610021
Pregnancy
category
Routes of
administration		By mouth, transdermal patch, intrauterine device, subcutaneous implant
Drug classProgestogen (medication); Progestin
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailability95% (range 85–100%)[4][5]
Protein binding98% (50% to albumin, 48% to SHBGTooltip sex hormone-binding globulin)[4]
MetabolismLiver (reduction, hydroxylation, conjugation)[4][6]
Metabolites• 5α-Dihydro-LNG[4]
Elimination half-life24–32 hours[4]
ExcretionUrine: 20–67%
Feces: 21–34%[6]
Identifiers
  • (8R,9S,10R,13S,14S,17R)-13-ethyl-17-ethynyl-17-hydroxy-1,2,6,7,8,9,10,11,12,14,15,16-dodecahydrocyclopenta[a]phenanthren-3-one
CAS Number
PubChem CID
IUPHAR/BPS
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard100.011.227 Edit this at Wikidata
Chemical and physical data
FormulaC21H28O2
Molar mass312.453 g·mol−1
3D model (JSmol)
Melting point235 to 237 °C (455 to 459 °F)
  • CC[C@]12CC[C@H]3[C@H]([C@@H]1CC[C@]2(C#C)O)CCC4=CC(=O)CC[C@H]34
  • InChI=1S/C21H28O2/c1-3-20-11-9-17-16-8-6-15(22)13-14(16)5-7-18(17)19(20)10-12-21(20,23)4-2/h2,13,16-19,23H,3,5-12H2,1H3/t16-,17+,18+,19-,20-,21-/m0/s1 checkY
  • Key:WWYNJERNGUHSAO-XUDSTZEESA-N checkY
  (verify)

Levonorgestrel is a hormonal medication which is used in a number of birth control methods.[3][7] It is combined with an estrogen to make combination birth control pills.[8] As an emergency birth control, sold under the brand names Plan B One-Step and Julie, among others, it is useful within 72 hours of unprotected sex.[3][7][9] The more time that has passed since sex, the less effective the medication becomes, and it does not work after pregnancy (implantation) has occurred.[7] Levonorgestrel works by preventing ovulation or fertilization from occurring.[10] It decreases the chances of pregnancy by 57–93%.[11] In an intrauterine device (IUD), such as Mirena among others, it is effective for the long-term prevention of pregnancy.[7] A levonorgestrel-releasing implant is also available in some countries.[12]

Common side effects include nausea, breast tenderness, headaches, and increased, decreased, or irregular menstrual bleeding.[7] When used as an emergency contraceptive, if pregnancy occurs, there is no evidence that its use harms the fetus.[7] It is safe to use during breastfeeding.[7] Birth control that contains levonorgestrel will not change the risk of sexually transmitted infections.[7] It is a progestin and has effects similar to those of the hormone progesterone.[7] It works primarily by preventing ovulation and closing off the cervix to prevent the passage of sperm.[7]

Levonorgestrel was patented in 1960 and introduced for medical use together with ethinylestradiol in 1970.[13][14] It is on the World Health Organization's List of Essential Medicines.[15] It is available as a generic medication.[16] In the United States, levonorgestrel-containing emergency contraceptives are available over the counter (OTC) for all ages.[17] In 2020, it was the 323rd most commonly prescribed medication in the United States, with more than 800 thousand prescriptions.[18]

  1. ^ a b "Levonorgestrel Use During Pregnancy". Drugs.com. 23 March 2020. Archived from the original on 2 July 2020. Retrieved 29 June 2020.
  2. ^ "Jaydess 13.5 mg intrauterine delivery system - Summary of Product Characteristics (SmPC)". (emc). 1 July 2022. Archived from the original on 13 April 2021. Retrieved 1 July 2022.
  3. ^ a b c "Plan B One-Step- levonorgestrel tablet". DailyMed. 21 December 2022. Retrieved 26 December 2022.
  4. ^ a b c d e Cite error: The named reference pmid16112947 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference pmid8842581 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference ShoupeHaseltine2012 was invoked but never defined (see the help page).
  7. ^ a b c d e f g h i j "Progestins (Etonogestrel, Levonorgestrel, Norethindrone)". The American Society of Health-System Pharmacists. Archived from the original on 2015-09-07. Retrieved Aug 21, 2015.
  8. ^ Postgraduate Gynecology. Jaypee Brothers Medical Pub. 2011. p. 159. ISBN 9789350250822. Archived from the original on 2015-09-26.
  9. ^ "Levonorgestrel 1.5 mg Tablet Emergency Contraceptive: New Drug Application 21998, Supplement 5" (PDF). U.S. Food and Drug Administration.
  10. ^ "Now Is the Time to Change Label on Emergency Contraceptives". Relias Media | Online Continuing Medical Education | Relias Media - Continuing Medical Education Publishing. Retrieved 2022-08-16.
  11. ^ Gemzell-Danielsson K (November 2010). "Mechanism of action of emergency contraception". Contraception. 82 (5): 404–409. doi:10.1016/j.contraception.2010.05.004. PMID 20933113.
  12. ^ "Chapter 1". Research on reproductive health at WHO : biennial report 2000-2001. Geneva: World health organization. 2002. ISBN 9789241562089. Archived from the original on 2015-09-26.
  13. ^ Fischer J, Ganellin CR (2006). Analogue-based Drug Discovery. John Wiley & Sons. p. 479. ISBN 9783527607495. Archived from the original on 2021-08-28. Retrieved 2020-08-05.
  14. ^ Cite error: The named reference Roth2014 was invoked but never defined (see the help page).
  15. ^ World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
  16. ^ Hamilton RJ (2014). Tarascon pocket pharmacopoeia : 2014 deluxe lab-pocket edition (15th ed.). Sudbury: Jones & Bartlett Learning. pp. 310–312. ISBN 9781284053999. Archived from the original on 2015-09-26.
  17. ^ "FDA approves Plan B One-Step emergency contraceptive for use without a prescription for all women of child-bearing potential" (Press release). June 20, 2013. Archived from the original on 14 January 2016. Retrieved 2 February 2016.
  18. ^ "Levonorgestrel - Drug Usage Statistics". ClinCalc. Retrieved 7 October 2022.