Relugolix and Mifepristone: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Mifepristone
Relugolix
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.
Let's talk about taking mifepristone and relugolix together. Mifepristone can slow down a 'pump' in your body (called P-gp) that normally helps move relugolix along. When that pump is blocked, more relugolix can build up, which may make side effects more likely.
On top of that, both drugs can affect your heart's rhythm by lengthening something called the QT interval. Combined, that effect can add up. The good news is that this concern is theoretical and very manageable. Your care team can time your doses, watch your heart rhythm and blood minerals, and adjust things as needed. Keep taking both exactly as prescribed and check in with your pharmacist or doctor.
Effect: Mifepristone (P-gp inhibitor) may increase exposure to relugolix (P-gp substrate), raising the risk of adverse effects, plus additive QT prolongation from both agents.
- Mechanism: Inhibition of intestinal P-gp efflux increases relugolix AUC/Cmax; both drugs independently prolong QTc.
- Direction: Increased relugolix effect (neither is a prodrug in this context).
- Evidence: Theoretical; severity rated major. Onset unspecified.
- Management: Avoid coadministration if possible. If unavoidable, give relugolix first, separate by at least 6 hours, and monitor more closely. Relugolix may be interrupted up to 2 weeks; if held >7 days, restart with 360 mg loading dose then 120 mg daily. Correct electrolytes; consider periodic ECG and electrolyte monitoring.
What happens
Increased relugolix exposure and an increased risk of QT interval prolongation
Interaction Deep Dive
Do not use relugolix (a P-gp substrate) together with P-gp inhibitors, because doing so can raise relugolix exposure and thereby heighten the likelihood of adverse reactions. When such combined use cannot be avoided, give the relugolix-containing product first, keep the two doses at least 6 hours apart, and increase the frequency of monitoring for adverse reactions12. Relugolix therapy may be paused for as long as 2 weeks to allow a brief course of a P-gp inhibitor. Once the P-gp inhibitor is stopped, relugolix can be resumed. When relugolix has been withheld for more than 7 days, reinitiate it using a 360 mg loading dose on day one and then continue at 120 mg once daily1. Giving relugolix alongside medications that prolong the QT interval can produce additive effects on the QT interval. In patients with congenital long QT syndrome, congestive heart failure, or frequent electrolyte abnormalities, as well as those receiving drugs recognized to prolong the QT interval, weigh whether the benefits of androgen deprivation therapy such as relugolix outweigh the potential risks. Correct any electrolyte abnormalities and consider periodic monitoring of ECGs and electrolytes1.
Why it happens (mechanism)
Inhibition of P-gp-mediated efflux transport of relugolix; additive QT interval prolongation
How to manage this interaction
This combination can be managed. Your care team will weigh whether both drugs are truly needed, especially if you have heart rhythm concerns, heart failure, or electrolyte problems.
- Keep taking both as prescribed unless your doctor tells you otherwise.
- If used together, the team may have you take relugolix first and separate the doses by at least 6 hours.
- They may monitor you more closely, including periodic ECGs and blood tests to check and correct minerals like potassium and magnesium.
- In some cases relugolix may be paused during a short course of mifepristone and restarted afterward (sometimes with a loading dose).
Ask your pharmacist or prescriber how they plan to time and monitor these medications for you.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) When relugolix (a P-gp substrate) was given together with erythromycin (a P-gp and CYP3A inhibitor), the AUC and Cmax of relugolix rose by 3.5-fold and 2.9-fold, respectively 1.
Common questions
Can I take Relugolix and Mifepristone together?
Mifepristone can raise relugolix levels and both can affect heart rhythm, so this combo is best avoided; if used together, your team will space the doses and monitor your ECG and electrolytes. Keep taking both as prescribed and confirm the plan with your pharmacist or doctor. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Relugolix and Mifepristone interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Relugolix and Mifepristone interaction managed?
This combination can be managed. Your care team will weigh whether both drugs are truly needed, especially if you have heart rhythm concerns, heart failure, or electrolyte problems. Keep taking both as prescribed unless your doctor tells you otherwise. If used together, the team may have you take relugolix first and separate the doses by at least 6 hours. They may monitor you more closely, includi… Management is individual — always follow your own care team's guidance.
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 Relugolix or Mifepristone 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 (2)
- Product Information: ORGOVYX oral tablets, relugolix oral tablets. Sumitomo Pharma America, Inc (per FDA), Marlborough, MA, 2025. DailyMed
- Product Information: MYFEMBREE(R) oral tablets, relugolix, estradiol, norethindrone acetate oral tablets. Myovant Sciences Inc (per FDA), Brisbane, CA, 2021. DailyMed
Keep reading about Mifepristone
Keep reading about Relugolix
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