Relugolix and Maribavir: 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
Maribavir
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 maribavir (Livtencity) and relugolix (Orgovyx). Here's what's going on: maribavir can slow down a 'pump' in your gut called P-gp that normally helps move relugolix out of your body. When that pump is blocked, more relugolix builds up in your blood. In a similar study with another blocker, relugolix levels rose about 3.5 times higher.
More relugolix means a higher chance of its side effects, like hot flashes, tiredness, or changes in blood pressure. The good news is your care team can manage this safely by adjusting timing, watching you more closely, or choosing another option. Please don't stop either medicine on your own. Just talk with your pharmacist or doctor.
Effect: Increased relugolix exposure. Maribavir inhibits P-gp-mediated efflux of relugolix (a P-gp substrate), raising systemic exposure and adverse-reaction risk.
Magnitude: Not established for this pair; a study with erythromycin (P-gp inhibitor) increased relugolix AUC ~3.5-fold and Cmax ~2.9-fold.
Evidence: Probable. Severity: Major. Onset: Unspecified.
Management:
- Avoid concomitant use when possible.
- If unavoidable, give relugolix (or relugolix/estradiol/norethindrone) first, separate by at least 6 hours, and monitor adverse reactions more frequently.
- Relugolix may be interrupted up to 2 weeks for short P-gp inhibitor courses; if held >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, because doing so can raise relugolix exposure and thereby heighten the likelihood of adverse reactions linked to relugolix. When coadministration cannot be avoided, 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 interrupted for more than 7 days, it should be restarted using a loading dose of 360 mg 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
This combination is manageable with a plan from your care team. Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise.
Your team may do one or more of the following:
- Take your relugolix dose first and separate the two medicines by at least 6 hours.
- Watch you more closely for relugolix side effects while you're on both.
- For a short course of maribavir, they may briefly pause relugolix and restart it afterward, using a loading dose if it was held more than 7 days.
Ask your pharmacist or doctor before changing any timing or dose, and report new or worsening side effects.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In a study evaluating drug interactions, giving relugolix (a P-gp substrate) together with erythromycin (a P-gp inhibitor) raised the AUC of relugolix by 3.5-fold and the Cmax by 2.9-fold 1.
Common questions
Can I take Relugolix and Maribavir together?
Maribavir can raise relugolix levels by blocking a gut pump, increasing side-effect risk, so let your care team space the doses and monitor you closely. Do not stop or change either drug on your own. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Relugolix and Maribavir 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 Maribavir interaction managed?
This combination is manageable with a plan from your care team. Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Your team may do one or more of the following: Take your relugolix dose first and separate the two medicines by at least 6 hours. Watch you more closely for relugolix side effects while you're on both. For a short course of maribavir, they may… 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 Relugolix or Maribavir 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 Maribavir
Keep reading about Relugolix
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.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist