Relugolix and Vemurafenib: 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
Vemurafenib
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.
You've been prescribed vemurafenib (Zelboraf), a cancer medicine, along with relugolix (Orgovyx). Vemurafenib can block a transporter (called P-gp) that normally helps push relugolix out of your body. When that happens, more relugolix can build up, which may lead to more side effects.
On top of that, both drugs can affect your heart's rhythm by lengthening something called the QT interval. Together, that effect can add up. The good news is your care team can manage this by spacing out your doses, checking your heart with an ECG, watching your blood minerals, and adjusting things as needed. Keep taking both exactly as prescribed and let your doctor or pharmacist know about any dizziness, fainting, or a pounding heart.
Effect: Vemurafenib (P-gp inhibitor) may increase exposure of relugolix (P-gp substrate), plus additive QT prolongation since both agents can prolong QTc.
- Mechanism: Inhibition of P-gp-mediated intestinal efflux of relugolix; additive PD effect on cardiac repolarization.
- Direction: Increased relugolix AUC/Cmax; neither drug is a prodrug.
- Evidence/onset: Theoretical; onset unspecified. Severity major.
- Management: Avoid if possible. If unavoidable, give relugolix first and separate by at least 6 hours; monitor for adverse effects. Consider interrupting relugolix for short P-gp inhibitor courses (up to 2 weeks); if held >7 days, resume with 360 mg loading dose then 120 mg daily. Correct electrolytes; obtain periodic ECGs. Weigh ADT benefit against risk in long QT, CHF, or electrolyte-prone patients.
What happens
Increased relugolix exposure and an increased risk of QT interval prolongation
Interaction Deep Dive
Relugolix, a P-gp substrate, should not be taken together with P-gp inhibitors, because doing so can raise relugolix exposure and thereby heighten the likelihood of adverse reactions. When coadministration 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. For a brief course of a P-gp inhibitor, relugolix therapy may be paused for as long as 2 weeks, and relugolix can be restarted once the P-gp inhibitor has been stopped. When relugolix has been interrupted for more than 7 days, resume it with a 360 mg loading dose on the first day, followed by 120 mg once daily thereafter1. Giving relugolix alongside medications that prolong the QT interval may produce additive QT effects. In patients who have congenital long QT syndrome, congestive heart failure, or recurrent electrolyte disturbances, as well as in those receiving drugs known to prolong the QT interval, weigh whether the benefits of androgen deprivation therapy such as relugolix are greater than the possible risks. Electrolyte imbalances should be corrected, and periodic ECG and electrolyte monitoring should be considered1.
Why it happens (mechanism)
Inhibition of P-gp-mediated efflux transport of relugolix; additive QT interval prolongation
How to manage this interaction
Both medicines are important, so don't stop either on your own. Here is how care teams typically handle this combination:
- Your team may avoid using them together when possible, or briefly pause relugolix during a short course of vemurafenib.
- If both are needed, they may have you take relugolix first and separate the doses by at least 6 hours.
- They may check ECGs and blood minerals (electrolytes) periodically and correct any imbalances.
- Your dose and monitoring may be individualized based on your heart history.
Report any fainting, dizziness, or irregular heartbeat to your pharmacist or doctor right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) Giving relugolix (a P-gp substrate) together with erythromycin (a P-gp and CYP3A inhibitor) raised the AUC and Cmax of relugolix by 3.5-fold and 2.9-fold, respectively 1.
Common questions
Can I take Relugolix and Vemurafenib together?
Vemurafenib can raise relugolix levels and both can affect heart rhythm, so this combination is best avoided; if used together, expect spaced dosing and extra heart and electrolyte monitoring arranged by your care team. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Relugolix and Vemurafenib 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 Vemurafenib interaction managed?
Both medicines are important, so don't stop either on your own. Here is how care teams typically handle this combination: Your team may avoid using them together when possible, or briefly pause relugolix during a short course of vemurafenib. If both are needed, they may have you take relugolix first and separate the doses by at least 6 hours. They may check ECGs and blood minerals (electrolytes) p… 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 Vemurafenib 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 Vemurafenib
Keep reading about Relugolix
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