Relugolix and Flibanserin: 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
Flibanserin
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.
If you take Addyi (flibanserin) along with Orgovyx (relugolix), here is what to know. Flibanserin can block a natural "pump" in your body called P-gp that normally helps move relugolix along and clear it out. When that pump is slowed, more relugolix can build up in your blood, which may raise your chance of side effects from relugolix.
The good news is your care team can manage this. They may space the two medicines apart, watch you more closely, or adjust your plan. Please don't stop or change either medicine on your own, just talk with your pharmacist or doctor so they can help you take both safely.
Effect: Increased relugolix exposure. Flibanserin inhibits P-gp, reducing efflux of relugolix (a P-gp substrate), raising its systemic exposure and risk of adverse reactions.
- Direction: Increased relugolix effect/toxicity (relugolix is not a prodrug).
- Magnitude: Reference P-gp inhibitor erythromycin raised relugolix AUC ~3.5-fold and Cmax ~2.9-fold.
- Evidence: Probable; severity major.
- Management: Avoid combination. If unavoidable, give relugolix first, separate dosing by at least 6 hours, and monitor for adverse reactions more frequently. Relugolix may be interrupted 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
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 relugolix-related adverse reactions. When coadministration cannot be avoided, give relugolix or relugolix/estradiol/norethindrone acetate first, allow a gap of no less than 6 hours between doses, and increase the frequency of monitoring for adverse reactions12. Relugolix therapy may be paused for up to 2 weeks to accommodate a brief course of certain P-gp inhibitors, resuming once the P-gp inhibitor has been stopped. Should relugolix be interrupted for more than 7 days, resume it 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 the AUC and Cmax of relugolix by 3.5-fold and 2.9-fold, respectively1.
Why it happens (mechanism)
Inhibition of P-gp-mediated efflux transport of relugolix
How to manage this interaction
Your care team will usually try to avoid using these two together when possible. If both are needed, they have clear ways to manage it:
- Take relugolix first and separate the two doses by at least 6 hours.
- Expect closer monitoring for relugolix side effects.
- In some cases relugolix may be paused briefly and restarted after flibanserin is stopped, with dosing individualized by your team.
Keep taking both exactly as prescribed and don't adjust anything yourself. Ask your pharmacist or prescriber how best to time these 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 examining 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 its Cmax by 2.9-fold 1.
Common questions
Can I take Relugolix and Flibanserin together?
Flibanserin can raise relugolix levels by blocking P-gp, increasing side-effect risk, so this combination is best avoided; if used together, separate doses by at least 6 hours (relugolix first) and let your care team monitor you closely. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Relugolix and Flibanserin 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 Flibanserin interaction managed?
Your care team will usually try to avoid using these two together when possible. If both are needed, they have clear ways to manage it: Take relugolix first and separate the two doses by at least 6 hours. Expect closer monitoring for relugolix side effects. In some cases relugolix may be paused briefly and restarted after flibanserin is stopped, with dosing individualized by your team. Keep taking… 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 Flibanserin 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 Flibanserin
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.
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