Vanzacaftor and Relugolix: 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
Relugolix
Vanzacaftor
No brand names on record
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.
Here's what's going on. Relugolix (Orgovyx) is cleared out of your body partly by a pump in your gut called P-gp. Vanzacaftor can slow that pump down. When the pump slows, more relugolix stays in your body, so the level rises. In studies with a similar pump-blocker, relugolix levels went up about three times higher.
The concern is not that the drug stops working, it's that higher levels can mean more side effects, like hot flashes, fatigue, or blood pressure changes. The good news is your care team can manage this by spacing the doses out and watching you a little more closely. Please don't change anything on your own, just check with your pharmacist or doctor.
Mechanism: Relugolix is a P-gp substrate; vanzacaftor is expected to inhibit P-gp-mediated intestinal efflux, reducing relugolix elimination and increasing exposure. Neither drug is a prodrug, so this raises active relugolix levels.
- Direction/magnitude: Increased relugolix AUC/Cmax. Reference P-gp inhibitor erythromycin raised AUC 3.5-fold and Cmax 2.9-fold.
- Evidence: Probable. Severity major.
- Management: Avoid concomitant use if possible. If unavoidable, give relugolix (or relugolix/estradiol/norethindrone) first and separate by at least 6 hours; monitor more frequently for relugolix adverse reactions. Relugolix may be interrupted up to 2 weeks for short P-gp inhibitor courses; if interrupted >7 days, restart with 360 mg loading dose then 120 mg daily.
What happens
Increased relugolix exposure
Interaction Deep Dive
Do not use relugolix (a P-gp substrate) together with P-gp inhibitors, since this can raise relugolix exposure and thereby heighten the likelihood of relugolix-related adverse reactions. When such combined use cannot be prevented, give relugolix or relugolix/estradiol/norethindrone acetate first, allow a gap of at least 6 hours between doses, and increase the frequency of monitoring for adverse reactions12. Relugolix therapy may be paused for as long as 2 weeks to accommodate a brief course of certain P-gp inhibitors, and relugolix can be resumed once the P-gp inhibitor has been stopped. Should relugolix be held for more than 7 days, reinitiate it with a 360 mg loading dose on day one, followed by 120 mg once daily thereafter. In a drug interaction study, giving relugolix (P-gp substrate) alongside erythromycin (P-gp inhibitor) raised relugolix AUC by 3.5-fold and Cmax by 2.9-fold1.
Why it happens (mechanism)
Inhibition of P-gp-mediated efflux transport of relugolix
How to manage this interaction
The main goal is to keep relugolix levels from climbing too high. Your care team may prefer to avoid using these together. When both are needed, they have clear ways to handle it.
- They may have you take relugolix (or the combination product) first and separate it from vanzacaftor by at least 6 hours.
- They may monitor you more closely for relugolix side effects.
- For a short course of the other drug, relugolix may be paused for up to 2 weeks and restarted afterward, sometimes with a loading dose your team will manage.
Keep taking both exactly as prescribed and ask your pharmacist or doctor before making any change.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) A drug interaction study found that giving relugolix (a P-gp substrate) together with erythromycin (a P-gp inhibitor) raised the AUC and Cmax of relugolix by 3.5-fold and 2.9-fold, respectively 1.
Common questions
Can I take Vanzacaftor and Relugolix together?
Vanzacaftor can raise relugolix levels by blocking a gut pump, increasing the risk of relugolix side effects; your care team may avoid the combo, space the doses at least 6 hours apart, or monitor you more closely. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Vanzacaftor and Relugolix 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 Vanzacaftor and Relugolix interaction managed?
The main goal is to keep relugolix levels from climbing too high. Your care team may prefer to avoid using these together. When both are needed, they have clear ways to handle it. They may have you take relugolix (or the combination product) first and separate it from vanzacaftor by at least 6 hours. They may monitor you more closely for relugolix side effects. For a short course of the other drug… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Vanzacaftor or Relugolix 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 Relugolix
Keep reading about Vanzacaftor
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