Clinical data | |
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Trade names | Mifeprex |
AHFS/Drugs.com | Monograph |
MedlinePlus | a600042 |
Pregnancy category |
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Routes of administration |
By mouth |
ATC code | G03XB01 (WHO) |
Legal status | |
Legal status |
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Pharmacokinetic data | |
Bioavailability | 69% |
Protein binding | 98% |
Metabolism | Liver |
Excretion | Fecal: 83%; Kidney: 9% |
Identifiers | |
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CAS Number | 84371-65-3 |
PubChem (CID) | 55245 |
IUPHAR/BPS | 2805 |
DrugBank | DB00834 |
ChemSpider | 49889 |
UNII | 320T6RNW1F |
KEGG | D00585 |
ChEBI | CHEBI:50692 |
ChEMBL | CHEMBL157 |
ECHA InfoCard | 100.127.911 |
Chemical and physical data | |
Formula | C29H35NO2 |
Molar mass | 429.60 g/mol |
3D model (Jmol) | Interactive image |
Density | 1.189 g/cm3 |
Melting point | 194 °C (381 °F) |
Boiling point | 629 °C (1,164 °F) |
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Mifepristone, also known as RU-486, is a medication typically used with misoprostol to bring about an abortion. This combination is more than 95% effective during the first 50 days of pregnancy. It is also effective in the second trimester of pregnancy. Two weeks after use effectiveness should be verified. It is taken by mouth.
Common side effects include abdominal pain, feeling tired, and vaginal bleeding. Serious side effects may include heavy vaginal bleeding, bacterial infection, and a malformed baby if the pregnancy does not end. If used, appropriate follow up care needs to be available. Mifepristone works by blocking the effects of progesterone and causing contractions of the uterus.
Mifepristone was developed in 1980 and came into use in France in 1987. It became available in the United States in 2000. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Mifepristone was approved by Health Canada in July 2015 and is expected to become available in Canada in January 2017. Cost and availability limits access in many parts of the developing world. In the United States it costs more than US$200 (equivalent to $202.08 in 2016) a dose.
Mifepristone followed by a prostaglandin analog (misoprostol or gemeprost) is used for medical abortion.
A 2011 evidence-based clinical guideline by the Royal College of Obstetricians and Gynaecologists (RCOG) says medical abortion using mifepristone followed by the prostaglandin analog misoprostol is effective and appropriate at any gestational age.
A 2012 technical and policy guidance book and a 2014 clinical practice handbook by the World Health Organization (WHO) recommend mifepristone followed by the prostaglandin analog misoprostol for first and second trimester medical abortions.