Last update June 22, 2022


Likely Compatibility

Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.

Antiprogestin which derives from Norethisterone, Mifepristone is a cortisol receptor blocker used to treat Cushing's syndrome and to terminate pregnancies up to 50-70 days' gestation.

Its high plasma protein-binding capacity and large volume of distribution (Sarkar 2002)  explains that excretion into breast milk is clinically non-significant. It achieves very low levels in breast milk at a maternal dose of 600 mg or undetectable at maternal dose of 200 mg. (Sääv 2010)

The punctual use of mifepristone does not contraindicate breastfeeding. (LactMed, Bettahar 2016)

When used with semi-experimental purposes due to its anti-androgenic and antiglucocorticoid properties a continuous administration and / or large doses is required. There is no experience in connection with breastfeeding. Those pathologies in which it is often used on a continuous basis by themselves are not compatible with breastfeeding.


We do not have alternatives for 米非司酮.

Suggestions made at e-lactancia are done by APILAM team of health professionals, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it. The pharmaceutical industry contraindicates breastfeeding, mistakenly and without scientific reasons, in most of the drug data sheets.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

Your contribution is essential for this service to continue to exist. We need the generosity of people like you who believe in the benefits of breastfeeding.

Thank you for helping to protect and promote breastfeeding.

José María Paricio, founder of e-lactancia.

Other names

米非司酮 is Mifepristone in Chinese.

Is written in other languages:


Main tradenames from several countries containing 米非司酮 in its composition:


Variable Value Unit
Oral Bioavail. 69 %
Molecular weight 430 daltons
Protein Binding 98 %
VD 1.5 l/Kg
pKa 12.87 -
Tmax 1.5 hours
18 hours
M/P ratio 0.01 - 0.04 -
Theoretical Dose < 0.026 mg/Kg/d
Relative Dose < 0.5 %


  1. AEMPS. Mifepristona. Ficha técnica. 2015 Full text (in our servers)
  2. Sääv I, Fiala C, Hämäläinen JM, Heikinheimo O, Gemzell-Danielsson K. Medical abortion in lactating women--low levels of mifepristone in breast milk. Acta Obstet Gynecol Scand. 2010 Abstract Full text (link to original source) Full text (in our servers)
  3. Grunberg SM, Weiss MH, Russell CA, Spitz IM, Ahmadi J, Sadun A, Sitruk-Ware R. Long-term administration of mifepristone (RU486): clinical tolerance during extended treatment of meningioma. Cancer Invest. 2006 Abstract
  4. FDA. Mifepristone. Drug Summary. 2004 Full text (in our servers)
  5. Baird DT. Antigestogens. Br Med Bull. 1993 Abstract

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