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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 | |
Legal status |
|
Pharmacokinetic data | |
Bioavailability | 95% (range 85–100%) [2] [3] |
Protein binding | 98% (50% to albumin, 48% to SHBG ) [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] |
Identifiers | |
| |
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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| |
(verify) |
Levonorgestrel is a hormonal medication which is used in a number of birth control methods. [6] It is combined with an estrogen to make combination birth control pills. [8] As an emergency birth control, sold under the brand name Plan B among others, it is useful within 120 hours of unprotected sex. [6] The more time that has passed since sex, the less effective the medication becomes, and it does not work after pregnancy ( implantation) has occurred. [6] It decreases the chances of pregnancy by 57 to 93%. [9] In an intrauterine device (IUD), such as Mirena among others, it is effective for the long-term prevention of pregnancy. [6] A levonorgestrel-releasing implant is also available in some countries. [10]
Common side effects include nausea, breast tenderness, headaches, and increased, decreased, or irregular menstrual bleeding. [6] When used as an emergency contraceptive, if pregnancy occurs, there is no evidence that its use harms the baby. [6] It is safe to use during breastfeeding. [6] Birth control that contains levonorgestrel will not change the risk of sexually transmitted infections. [6] It is a progestin and has effects similar to those of the hormone progesterone. [6] It works primarily by preventing ovulation and closing off the cervix to prevent the passage of sperm. [6]
Levonorgestrel was patented in 1960 and introduced for medical use together with ethinylestradiol in 1970. [11] [12] It is on the World Health Organization's List of Essential Medicines. [13] It is available as a generic medication. [14] The wholesale cost in the developing world is between $0.23 and $1.65 US for the dose required for emergency birth control. [15] In the United States, levonorgestrel-containing emergency birth control is available over the counter (OTC) for all ages. [16] In 2016, it was the 223rd most commonly prescribed medication in the United States, with more than two million prescriptions. [17]
MSF2020
was invoked but never defined (see the
help page).WHO2020DDD
was invoked but never defined (see the
help page).Roth2014
was invoked but never defined (see the
help page).
![]() | |
![]() | |
Clinical data | |
---|---|
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 | |
Legal status |
|
Pharmacokinetic data | |
Bioavailability | 95% (range 85–100%) [2] [3] |
Protein binding | 98% (50% to albumin, 48% to SHBG ) [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] |
Identifiers | |
| |
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) |
| |
| |
(verify) |
Levonorgestrel is a hormonal medication which is used in a number of birth control methods. [6] It is combined with an estrogen to make combination birth control pills. [8] As an emergency birth control, sold under the brand name Plan B among others, it is useful within 120 hours of unprotected sex. [6] The more time that has passed since sex, the less effective the medication becomes, and it does not work after pregnancy ( implantation) has occurred. [6] It decreases the chances of pregnancy by 57 to 93%. [9] In an intrauterine device (IUD), such as Mirena among others, it is effective for the long-term prevention of pregnancy. [6] A levonorgestrel-releasing implant is also available in some countries. [10]
Common side effects include nausea, breast tenderness, headaches, and increased, decreased, or irregular menstrual bleeding. [6] When used as an emergency contraceptive, if pregnancy occurs, there is no evidence that its use harms the baby. [6] It is safe to use during breastfeeding. [6] Birth control that contains levonorgestrel will not change the risk of sexually transmitted infections. [6] It is a progestin and has effects similar to those of the hormone progesterone. [6] It works primarily by preventing ovulation and closing off the cervix to prevent the passage of sperm. [6]
Levonorgestrel was patented in 1960 and introduced for medical use together with ethinylestradiol in 1970. [11] [12] It is on the World Health Organization's List of Essential Medicines. [13] It is available as a generic medication. [14] The wholesale cost in the developing world is between $0.23 and $1.65 US for the dose required for emergency birth control. [15] In the United States, levonorgestrel-containing emergency birth control is available over the counter (OTC) for all ages. [16] In 2016, it was the 223rd most commonly prescribed medication in the United States, with more than two million prescriptions. [17]
MSF2020
was invoked but never defined (see the
help page).WHO2020DDD
was invoked but never defined (see the
help page).Roth2014
was invoked but never defined (see the
help page).