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mifepristone (Mifeprex, RU-486, Mifegyne)
Controversial abortion pill. Available 11/2000;
Indications:
- termination of pregnancy of < 70 day duration
Dosage:
1) 3 office visits vs dispensed by mail [6]
2) 1st visit: 200 mg mifepristone tablet
- formerly 600 mg (3 tablets) [4]
- not necessary to observe in a medical facility
3) 2 days later, 400 ug of buccal misoprostol
- unclear with new labeling that this step required [4]
- vaginal misoprostol 24 hours later [5]
4) doxycline 100 mg PO BID
5) follow-up after 2 weeks to confirm termination of pregnancy
Mechanism of action:
1) anti-progestin; interrupts pregnancy
2) misoprostol stimulates uterine contractions
3) combination of mifepristone followed by misoprostol is 95% effective in terminating pregnancies during the 1st 7 weeks
4) RU486 also antagonizes glucocorticoid receptors
Adverse effects:
- septic death (4 cases)
- Clostridium sordellii etiologic agent in 2 of 4 cases [2] Mifeprex info: (877) 432-7596 or www.earlyoptionpill.com
General
endocrine agent
Database Correlations
PUBCHEM correlations
References
- Prescriber's Letter 7(10):56 2000
- FDA Medwatch
http://www.fda.gov/medwatch/safety/2005/safety05.htm#Mifeprex
http://www.fda.gov/medwatch/safety/2006/safety06.htm#Mifeprex
- FDA Drug Safety. March 30, 2016
Mifeprex (mifepristone) Information
http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm111323.htm
- Greene MF, Drazen JM
A New Label for Mifepristone.
N Engl J Med 2016; 374:2281-2282. June 9, 2016
PMID: 27276566
http://www.nejm.org/doi/full/10.1056/NEJMe1604462
- Schreiber CA, Creinin MD, Atrio J et al.
Mifepristone pretreatment for the medical management of
early pregnancy loss.
N Engl J Med 2018 Jun 7; 378:2161. June 7, 2018
PMID: 29874535
https://www.nejm.org/doi/10.1056/NEJMoa1715726
- Westhoff CL.
A better medical regimen for the management of miscarriage.
N Engl J Med 2018 Jun 7; 378:2232. June 7, 2018
PMID: 29874544
https://www.nejm.org/doi/10.1056/NEJMe1804945
- US Food & Drug Administration. Jan 24, 2023
Information about Mifepristone for Medical Termination of Pregnancy
Through Ten Weeks Gestation.
https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/information-about-mifepristone-medical-termination-pregnancy-through-ten-weeks-gestation