User:Mr. Ibrahem/Levonorgestrel
From Wikipedia, the free encyclopedia
Levonorgestrel is a hormonal medication which is used in a number of birth control methods.[5] It is combined with an estrogen to make combination birth control pills.[6] As an emergency birth control, sold under the brand name Plan B among others, it is useful within 120 hours of unprotected sex.[5] The more time that has passed since sex, the less effective the medication becomes, and it does not work after pregnancy (implantation) has occurred.[5] It decreases the chances of pregnancy by 57 to 93%.[7] In an intrauterine device (IUD), such as Mirena among others, it is effective for the long-term prevention of pregnancy.[5] A levonorgestrel-releasing implant is also available in some countries.[8]
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Clinical data | |
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Trade names | Plan B, others |
Other names | LNG; 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.com | Monograph |
MedlinePlus | a610021 |
Pregnancy category | |
Routes of administration | By mouth, transdermal patch, intrauterine device, subcutaneous implant |
Drug class | Progestogen; progestin |
Legal status | |
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Pharmacokinetic data | |
Bioavailability | 95% (range 85–100%)[2][3] |
Protein binding | 98% (50% to albumin, 48% to SHBGTooltip sex hormone-binding globulin)[2] |
Metabolism | Liver (reduction, hydroxylation, conjugation)[2][4] |
Metabolites | • 5α-Dihydro-@@@6@@@[2] |
Elimination half-life | 24–32 hours[2] |
Excretion | Urine: 20–67% Feces: 21–34%[4] |
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Chemical and physical data | |
Formula | C21H28O2 |
Molar mass | 312.453 g·mol−1 |
3D model (JSmol) | |
Melting point | 235 to 237 °C (455 to 459 °F) |
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Common side effects include nausea, breast tenderness, headaches, and increased, decreased, or irregular menstrual bleeding.[5] When used as an emergency contraceptive, if pregnancy occurs, there is no evidence that its use harms the baby.[5] It is safe to use during breastfeeding.[5] Birth control that contains levonorgestrel will not change the risk of sexually transmitted infections.[5] It is a progestin and has effects similar to those of the hormone progesterone.[5] It works primarily by preventing ovulation and closing off the cervix to prevent the passage of sperm.[5]
Levonorgestrel was patented in 1960 and introduced for medical use together with ethinylestradiol in 1970.[9][10] It is on the World Health Organization's List of Essential Medicines.[11] It is available as a generic medication.[12] The wholesale cost in the developing world is between $0.23 and $1.65 US for the dose required for emergency birth control.[13] In the United States, levonorgestrel-containing emergency birth control is available over the counter (OTC) for all ages.[14] In 2016, it was the 223rd most commonly prescribed medication in the United States, with more than two million prescriptions.[15]