Mifepristone and Irbesartan: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Mifepristone
Irbesartan
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 exposure to irbesartan
Interaction Deep Dive
Concomitant administration of irbesartan, a CYP2C9 substrate2, with mifepristone, a CYP2C9 inhibitor, may lead to increased exposure to irbesartan. Although not specifically studied with irbesartan, coadministration of a single 40 mg fluvastatin dose (a CYP2C8/2C9 substrate) in healthy subjects receiving mifepristone (Korlym(TM)) 1200 mg orally once daily led to significantly increased fluvastatin exposure, with geometric mean ratios (with/without coadministration) of fluvastatin AUC and Cmax of 3.57 and 1.76, respectively. The lowest dose of irbesartan should be used when given concomitantly with mifepristone (Korlym(TM)) and patients should be monitored closely for irbesartan adverse effects. Due to the long terminal half-life of mifepristone after reaching steady state, allow at least 2 weeks following cessation of mifepristone (Korlym(TM)) before increasing the dose of irbesartan 1.
Why it happens (mechanism)
Inhibition of CYP2C9-mediated metabolism of irbesartan
Common questions
Can I take Mifepristone and Irbesartan together?
Increased exposure to irbesartan Always confirm with your pharmacist or prescriber before making any change.
How serious is the Mifepristone and Irbesartan interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
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 Irbesartan 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 anything you'd monitor while I'm on both?
References (2)
- Product Information: Korlym(TM) oral tablets, mifepristone oral tablets. Corcept Therapeutics (per manufacturer), Menlo Park, CA, 2012. DailyMed
- Product Information: AVAPRO(R) oral tablets, irbesartan oral tablets. Bristol-Myers Squibb Sanofi-Synthelabo Partnership (per FDA), New York, NY, 2012. DailyMed
Keep reading about Mifepristone
Keep reading about Irbesartan
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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