Mifepristone

Antiprogestins, selective progesterone receptor modulators

ATC code: G03XB01

Brand names: Mifeprex, Korlym (для синдрома Кушинга)

Updated 19 Jun 2026 · Methodology

Indications

Medical abortion

First line

First-line for medical abortion per 2022, 2020, 2015. Standard regimen – mifepristone 200 mg orally, then misoprostol 800 mcg buccally, sublingually, or vaginally 24–48 hours later. Up to 9 weeks: 95–98 % efficacy; 9–12 weeks: up to 95 % with possible repeat misoprostol doses. After 12 weeks – higher-dose regimens or surgical methods. Alternative – vacuum aspiration. WHO classifies medical abortion as primary care and supports access.

Sources

ICD-10: O04 · ICD-11: JA00.1

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Threatened miscarriage

Not recommended

Mifepristone is an antiprogestin and contraindicated when continuing pregnancy is desired. Off-protocol or impromptu use is unacceptable. In a patient with cramping or spotting in a wanted pregnancy, mifepristone is not indicated and is hazardous.

Sources

ICD-10: O20.0 · ICD-11: JA40.0

How to read tiers A–F

AStrong evidence – first or second line in international guidelines
BRecommended in selected cases
CStudy data contradict each other
DBenefit not proven, no documented harm
FDocumented harm, or risk without benefit

Mechanism of action

Selective antagonist of progesterone and glucocorticoid receptors. Blockade of endometrial progesterone receptors causes decidual necrosis, gestational sac detachment, cervical softening, and increased myometrial sensitivity to prostaglandins. Combined with misoprostol (a synthetic prostaglandin E1 analog, 24–48 hours after mifepristone), it provides medical abortion up to 12 weeks. Efficacy 95–98 % with proper use.

Safety

Boxed warning

FDA boxed warning: serious and sometimes fatal infections and bleeding after medical abortion. Patients must have access to emergency medical care for several days after misoprostol. Symptoms of serious complications require urgent hospital evaluation.

Contraindications

Suspected or confirmed ectopic pregnancy
Intrauterine device in place (remove first)
Chronic adrenal insufficiency
Long-term corticosteroid therapy
Bleeding disorders, anticoagulant therapy
Severe asthma (relative)
Hypersensitivity to mifepristone or misoprostol

Serious adverse effects

Severe bleeding requiring transfusion (about 0.1 % of cases)
Incomplete abortion requiring surgery (about 1 %)
Severe infection, septic shock (Clostridium sordellii — rare but reported cause of death)
Anaphylaxis (very rare)

Common adverse effects

Vaginal bleeding (part of expected effect)
Abdominal cramping
Nausea, vomiting
Diarrhea (from misoprostol)
Fatigue
Headache
Chills, fever (from misoprostol, usually transient)

Pregnancy: can you take Mifepristone?

AEMPS summary of product characteristics (section 4.6): in animals, the abortifacient effect of mifepristone prevents assessment of any teratogenic effect; at subabortive doses, malformations were seen in rabbits but not in rats, mice or monkeys. In clinical practice, rare cases of lower-limb malformations (including clubfoot) have been reported with mifepristone alone or combined with prostaglandins, possibly through amniotic band syndrome, but the data are too limited to say whether it is a human teratogen. Because of the risk of failure of medical termination and the risks to the fetus, the follow-up visit is mandatory. If an ongoing viable pregnancy is found and the woman still wants the termination, it is completed by another method; if she wishes to continue the pregnancy, it is closely monitored with ultrasound in a specialised centre, with particular attention to the limbs.

Breastfeeding: can you take Mifepristone?

Transfers into milk in small amounts. After a single dose, no feeding interruption is needed; with repeat dosing, skip feeds for 12 hours.

RID, infant dose via milk: 0.5%

Calculate RID Full profile on NIH LactMed ↗

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Practical notes

Timing and administration

Standard medical abortion regimen: day 1 — mifepristone 200 mg orally; day 2–3 (24–48 hours later) — misoprostol 800 mcg buccally, sublingually, or vaginally. After misoprostol — cramping abdominal pain, bleeding, and gestational sac expulsion within 4–24 hours. Follow-up at 1–2 weeks — clinical evaluation; ultrasound if needed to confirm complete abortion. Per 2022, routine confirmatory ultrasound is not mandatory in most cases.

Special situations

If pregnancy continues after failed medical abortion, the fetus is at increased malformation risk — informed decision-making is required regarding continuation or surgical completion. In Rh-negative patients beyond 8 weeks — anti-D immunoglobulin prophylaxis. Signs of serious complications (severe pain not relieved by NSAIDs, fever over 24 hours, bleeding above 2 pads per hour for more than 2 hours, foul-smelling discharge) — urgent ED presentation.

Label mentions26 mentions

Verbatim lines from the interaction sections, in the language of the label

From this drug’s label

Criticalanticoagulantsclass named in the label
«CONTRAINDICATIONS: Hemorrhagic disorders or concurrent anticoagulant therapy (risk of heavy bleeding)»
FDA, section 4 · Open on DailyMed
Criticalcorticosteroidsclass named in the label
«CONTRAINDICATIONS: Concurrent long-term corticosteroid therapy (risk of acute adrenal insufficiency)»
FDA, section 4 · Open on DailyMed
Majorcorticosteroidesclass named in the label
«1.- En todos los casos: Debido a la actividad antiglucocorticoidea de la mifepristona, la eficacia del tratamiento con corticoides a largo plazo, que incluye corticoides inhalados en pacientes…»
AEMPS, section 4.4 · Open on CIMA
ModerateCYP3A4 inhibitorsclass named in the label
«DRUG INTERACTIONS: CYP3A4 inhibitors can increase mifepristone concentrations. Use with caution. ( 7.2 )»
FDA, section 7 · Open on DailyMed
ModerateErythromycin
«La administración concomitante de mifepristona con itraconazol, un inhibidor del CYP3A4, aumentó 2,6 veces el AUC de la mifepristona y 5,1 y 1,5 veces la exposición de sus metabolitos 22-hidroxi…»
AEMPS, section 4.5 · Open on CIMA
ModerateErythromycin
«DRUG INTERACTIONS: Although specific drug or food interactions with mifepristone have not been studied, on the basis of this drug's metabolism by CYP 3A4, it is possible that ketoconazole…»
FDA, section 7 · Open on DailyMed
ModerateItraconazole
«La administración concomitante de mifepristona con itraconazol, un inhibidor del CYP3A4, aumentó 2,6 veces el AUC de la mifepristona y 5,1 y 1,5 veces la exposición de sus metabolitos 22-hidroxi…»
AEMPS, section 4.5 · Open on CIMA
ModerateItraconazole
«DRUG INTERACTIONS: Although specific drug or food interactions with mifepristone have not been studied, on the basis of this drug's metabolism by CYP 3A4, it is possible that ketoconazole…»
FDA, section 7 · Open on DailyMed
ModerateKetoconazole
«La administración concomitante de mifepristona con itraconazol, un inhibidor del CYP3A4, aumentó 2,6 veces el AUC de la mifepristona y 5,1 y 1,5 veces la exposición de sus metabolitos 22-hidroxi…»
AEMPS, section 4.5 · Open on CIMA
ModerateKetoconazole
«DRUG INTERACTIONS: Although specific drug or food interactions with mifepristone have not been studied, on the basis of this drug's metabolism by CYP 3A4, it is possible that ketoconazole…»
FDA, section 7 · Open on DailyMed
Acetylsalicylic acid
«Teóricamente puede producirse una disminución de la eficacia del método debido a las propiedades antiprostaglandina de los fármacos antiinflamatorios no esteroides (AINEs), incluida la aspirina…»
AEMPS, section 4.5 · Open on CIMA
AINEclass named in the label
«Teóricamente puede producirse una disminución de la eficacia del método debido a las propiedades antiprostaglandina de los fármacos antiinflamatorios no esteroides (AINEs), incluida la aspirina…»
AEMPS, section 4.5 · Open on CIMA
antiepilépticosclass named in the label
«Se ha demostrado que la administración concomitante de mifepristona con rifampicina, un inductor del CYP3A4, disminuye el AUC de la mifepristona en 6,3 veces y de sus metabolitos 22-hidroxi…»
AEMPS, section 4.5 · Open on CIMA
antiepilepticsclass named in the label
«DRUG INTERACTIONS: CYP450 3A4 is primarily responsible for the metabolism of mifepristone. CYP3A4 inducers such as rifampin, dexamethasone, St. John's Wort, and certain anticonvulsants (such as…»
FDA, section 7 · Open on DailyMed
Carbamazepine
«Se ha demostrado que la administración concomitante de mifepristona con rifampicina, un inductor del CYP3A4, disminuye el AUC de la mifepristona en 6,3 veces y de sus metabolitos 22-hidroxi…»
AEMPS, section 4.5 · Open on CIMA
Carbamazepine
«DRUG INTERACTIONS: CYP450 3A4 is primarily responsible for the metabolism of mifepristone. CYP3A4 inducers such as rifampin, dexamethasone, St. John's Wort, and certain anticonvulsants (such as…»
FDA, section 7 · Open on DailyMed
CYP3A4 inducersclass named in the label
«DRUG INTERACTIONS: CYP3A4 inducers can lower mifepristone concentrations. ( 7.1 )»
FDA, section 7 · Open on DailyMed
Dexamethasone
«DRUG INTERACTIONS: CYP450 3A4 is primarily responsible for the metabolism of mifepristone. CYP3A4 inducers such as rifampin, dexamethasone, St. John's Wort, and certain anticonvulsants (such as…»
FDA, section 7 · Open on DailyMed
Phenobarbital
«Se ha demostrado que la administración concomitante de mifepristona con rifampicina, un inductor del CYP3A4, disminuye el AUC de la mifepristona en 6,3 veces y de sus metabolitos 22-hidroxi…»
AEMPS, section 4.5 · Open on CIMA
Phenobarbital
«DRUG INTERACTIONS: CYP450 3A4 is primarily responsible for the metabolism of mifepristone. CYP3A4 inducers such as rifampin, dexamethasone, St. John's Wort, and certain anticonvulsants (such as…»
FDA, section 7 · Open on DailyMed
Phenytoin
«Se ha demostrado que la administración concomitante de mifepristona con rifampicina, un inductor del CYP3A4, disminuye el AUC de la mifepristona en 6,3 veces y de sus metabolitos 22-hidroxi…»
AEMPS, section 4.5 · Open on CIMA
Phenytoin
«DRUG INTERACTIONS: CYP450 3A4 is primarily responsible for the metabolism of mifepristone. CYP3A4 inducers such as rifampin, dexamethasone, St. John's Wort, and certain anticonvulsants (such as…»
FDA, section 7 · Open on DailyMed
Rifampicin
«Se ha demostrado que la administración concomitante de mifepristona con rifampicina, un inductor del CYP3A4, disminuye el AUC de la mifepristona en 6,3 veces y de sus metabolitos 22-hidroxi…»
AEMPS, section 4.5 · Open on CIMA

From other drugs’ labels

MajorFlurbiprofen
«Mifepristona: Como los AINEs pueden reducir el efecto de la mifepristona, no deben utilizarse en los 8-12 días posteriores a la administración de la mifepristona.»
AEMPS, section 4.5 · Open on CIMA
MinorDexketoprofen
«Mifepristona: existe un riesgo teórico de que los inhibidores de la síntesis de prostaglandinas alteren la eficacia de la mifepristona. Evidencias científicas limitadas sugieren que la…»
AEMPS, section 4.5 · Open on CIMA
Ibuprofen
«Mifepristona : teóricamente se puede producir una disminución de la eficacia de este medicamento debido a las propiedades antiprostaglandínicas de los AINEs. Las evidencias limitadas sugieren que la…»
AEMPS, section 4.5 · Open on CIMA

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Frequently asked

What is Mifepristone used for?

Mifepristone is evaluated for the following indications with varying evidence strength: Medical abortion (evidence tier A), Threatened miscarriage (evidence tier F). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Mifepristone?

Common side effects of Mifepristone (≥ 1 in 100): Vaginal bleeding (part of expected effect), Abdominal cramping, Nausea, vomiting, Diarrhea (from misoprostol), Fatigue, Headache. See the Safety section for uncommon and serious reactions.

Is Mifepristone safe during pregnancy?

Is Mifepristone compatible with breastfeeding?

Transfers into milk in small amounts. After a single dose, no feeding interruption is needed; with repeat dosing, skip feeds for 12 hours.

Who should not take Mifepristone?

Mifepristone is contraindicated in: Suspected or confirmed ectopic pregnancy; Intrauterine device in place (remove first); Chronic adrenal insufficiency; Long-term corticosteroid therapy; Bleeding disorders, anticoagulant therapy. Full list in the Safety section.

Does Mifepristone carry an FDA boxed warning?

Official sources

Direct links to regulator labels. Open in a new tab.

AEMPS / CIMALabel dated 09/11/2024
FDA / DailyMedLabel dated 06/06/2026

Other drugs in this group

Norelgestromin + Ethinylestradiol (transdermal patch), Norethisterone, Progesterone, micronized, Red clover (Trifolium pratense), Tibolone, Desogestrel, Estradiol valerate + Dienogest, Ethinylestradiol + Norgestimate