Mifepristone and Entrectinib: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Mifepristone
Entrectinib
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased entrectinib exposure, increased miFEPRIStone exposure and an increased frequency or severity of adverse reactions including increased risk of cardiac arrhythmias and an increased risk of QT interval prolongation
Interaction Deep Dive
Coadministration of miFEPRIStone (Korlym®) and entrectinib is contraindicated as it may increase entrectinib exposure. Concomitant use of miFEPRIStone with entrectinib may also increase miFEPRIStone exposure. Limit the dose of miFEPRIStone to 900 mg. Initiate entrectinib at least 2 weeks after stopping miFEPRIStone2. However, exert caution. Due to the slow elimination of miFEPRIStone (Mifeprex®), such interaction may be observed for a prolonged period after its administration 3. Concomitant use may also increase the frequency/severity of adverse reactions. If unavoidable, in adults and pediatric patients 2 years or older, reduce 600 mg starting entrectinib dose to 100 mg orally once daily, 400 mg or 300 mg to 50 mg once daily, 200 mg to 50 mg on alternate days and limit coadministration to 14 days or less. After discontinuation of miFEPRIStone for 3 to 5 elimination half-lives, resume the entrectinib dose that was taken prior to initiating miFEPRIStone. For pediatric patients with a starting dose less than 200 mg avoid coadministration with miFEPRIStone. Assess QT interval and electrolytes prior to initiation of entrectinib and periodically during treatment. Based on the severity of QTc interval prolongation, withhold entrectinib and then resume at same or reduced dose, or permanently discontinue 1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of entrectinib; inhibition of CYP3A4-mediated metabolism of miFEPRIStone; additive QT interval prolongation
Literature reports
2 reports — tap to read
a) Coadministration of itraconazole (a strong CYP3A inhibitor) with a single entrectinib dose of 100 mg increased entrectinib AUC(0 to inf) by 6-fold and Cmax by 1.7-fold 1.
b) In a drug interaction study, coadministration of miFEPRIStone 1200 mg once daily for 10 days and simvastatin (CYP3A4 substrate) 80 mg single dose, resulted in increased simvastatin AUC and Cmax by 10.40-fold and 7.02-fold, respectively. Also resulted in increased simvastatin acid AUC and Cmax by 15.7-fold and 18.20, respectively 2.
Common questions
Can I take Mifepristone and Entrectinib together?
Increased entrectinib exposure, increased miFEPRIStone exposure and an increased frequency or severity of adverse reactions including increased risk of cardiac arrhythmias and an increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.
How serious is the Mifepristone and Entrectinib interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Mifepristone or Entrectinib need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (3)
- Product Information: ROZLYTREK(R) oral capsules, pellets, entrectinib oral capsules, pellets. Genentech Inc (per FDA), South San Francisco, CA, 2023. DailyMed
- Product Information: KORLYM(R) oral tablets, mifepristone oral tablets. Corcept Therapeutics Incorporated (per Dailmed), Redwood City, CA, 2024. DailyMed
- Product Information: MIFEPREX(R) oral tablets, mifepristone oral tablets. Danco Laboratories, LLC (per FDA), New York, NY, 2023. DailyMed
Keep reading about Mifepristone
Keep reading about Entrectinib
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