Relugolix and Eliglustat: 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
Eliglustat
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 two medicines that can affect each other. Eliglustat (Cerdelga) blocks a natural "pump" in your body called P-glycoprotein, or P-gp. That pump normally helps move relugolix (Orgovyx) out of your system. When the pump is slowed down, more relugolix stays in your blood.
That means relugolix can build up to higher levels than intended, which may raise your chance of side effects. This is considered a serious pairing, but your care team can manage it by spacing the doses out, watching you more closely, or adjusting your plan. Don't stop or change either medicine on your own. Just check in with your pharmacist or doctor.
Effect: Increased relugolix exposure. Eliglustat is a P-gp inhibitor; relugolix is a P-gp substrate. Inhibition of intestinal P-gp-mediated efflux increases relugolix AUC and Cmax, raising the risk of relugolix-related adverse reactions.
Magnitude: By analogy, erythromycin (P-gp inhibitor) increased relugolix AUC ~3.5-fold and Cmax ~2.9-fold. Evidence: probable. Severity: major.
- Avoid concomitant use where possible.
- If unavoidable, give relugolix (or relugolix/estradiol/norethindrone) first, separate by at least 6 hours, and monitor for adverse reactions more frequently.
- Relugolix may be interrupted up to 2 weeks for short P-gp inhibitor courses; if interrupted >7 days, restart with a 360 mg loading dose then 120 mg daily.
What happens
Increased relugolix exposure
Interaction Deep Dive
Because relugolix is a P-gp substrate, taking it together with P-gp inhibitors can raise relugolix exposure and thereby heighten the likelihood of relugolix-related adverse reactions, so such combined use should be avoided. When coadministration cannot be avoided, give relugolix or the relugolix/estradiol/norethindrone acetate product first, allow a minimum of 6 hours between the doses, and increase the frequency of monitoring for adverse reactions12. For a brief course of certain P-gp inhibitors, relugolix therapy may be paused for as long as 2 weeks, with relugolix restarted once the P-gp inhibitor has been stopped. Should the relugolix interruption exceed 7 days, resume with a 360 mg loading dose on the first day, then proceed with 120 mg once daily. A drug interaction study found that giving relugolix (a P-gp substrate) alongside erythromycin (a 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
Both drugs can be used with care, but your team will usually try to avoid combining them when possible. If they must be used together, expect a plan like this:
- Take relugolix first, then separate the two medicines by at least 6 hours.
- Your team may monitor you more closely for relugolix side effects.
- In some cases relugolix may be paused during a short course of the other drug, then restarted (sometimes with a loading dose) per your prescriber.
Keep taking both exactly as prescribed, and ask your pharmacist or doctor how to space your doses and what side effects to watch for.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In a study of 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 Eliglustat together?
Eliglustat can raise relugolix levels by blocking the P-gp pump, increasing side-effect risk. Don't change anything yourself; ask your care team about spacing doses at least 6 hours apart and closer monitoring. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Relugolix and Eliglustat 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 Eliglustat interaction managed?
Both drugs can be used with care, but your team will usually try to avoid combining them when possible. If they must be used together, expect a plan like this: Take relugolix first, then separate the two medicines by at least 6 hours. Your team may monitor you more closely for relugolix side effects. In some cases relugolix may be paused during a short course of the other drug, then restarted (som… 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 Eliglustat 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 Eliglustat
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