Relugolix and Sparsentan: 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
Sparsentan
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 carried through your body by a kind of cellular "pump" called P-gp. Sparsentan (Filspari) can slow that pump down. When the pump is slowed, more relugolix can build up in your blood, which may make side effects (like hot flashes, tiredness, or digestive upset) more likely.
I want to reassure you that this is a manageable situation. This concern is based mostly on how these drugs behave in theory, not on lots of real-world reports. Your care team can watch you more closely and adjust your dose if needed. Please don't stop either medicine on your own, just check in with your pharmacist or doctor.
Mechanism: Sparsentan inhibits P-glycoprotein (P-gp)-mediated efflux. Relugolix is a sensitive P-gp substrate, so coadministration is expected to increase relugolix exposure (Cmax/AUC) and the risk of substrate-related adverse effects.
- Direction: Increased relugolix exposure (reduced efflux).
- Magnitude: Not quantified for relugolix; as reference, sparsentan raised digoxin Cmax ~61% and AUC ~18%.
- Onset: Unspecified.
- Evidence: Theoretical.
- Management: Monitor for relugolix-related adverse reactions; consider dose reduction of sensitive P-gp substrates when coadministered, individualized to the patient.
What happens
Increased P-gp substrate exposure and an increased risk of P-gp substrate-related adverse effects
Interaction Deep Dive
Because sparsentan acts as a P-gp inhibitor, giving it alongside sensitive P-gp substrates can raise the exposure of those transporter substrates. When digoxin (a P-gp substrate) was given together with sparsentan, its Cmax rose by 61% and its AUC(0-inf) rose by 18%. For P-gp substrates that have narrow therapeutic indices, watch for adverse reactions and think about lowering the dose when they are used together with sparsentan1.
Why it happens (mechanism)
Inhibition of P-gp-mediated efflux transport by sparsentan
How to manage this interaction
The good news: your care team can manage this by keeping a closer eye on you and tailoring your dose if needed.
- Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise.
- Your team may monitor you more closely for relugolix side effects (such as hot flashes, fatigue, or digestive symptoms).
- Your relugolix dose may be adjusted and individualized by your care team if side effects appear.
- Tell your pharmacist or doctor about any new or worsening symptoms, and confirm this combination is on their radar.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) When administered together with sparsentan, exposure to digoxin (a P-gp substrate) rose, with the Cmax increasing by 61% and the AUC(0-inf) increasing by 18% 1.
Common questions
Can I take Relugolix and Sparsentan together?
Sparsentan can slow the pump that clears relugolix, so relugolix levels may rise and side effects could increase. Keep taking both as prescribed and let your care team monitor and adjust your dose if needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Relugolix and Sparsentan interaction?
It is rated moderate. Can be significant — usually manageable with 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 Sparsentan interaction managed?
The good news: your care team can manage this by keeping a closer eye on you and tailoring your dose if needed. Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Your team may monitor you more closely for relugolix side effects (such as hot flashes, fatigue, or digestive symptoms). Your relugolix dose may be adjusted and individualized by your care team i… 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 Sparsentan 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 anything you'd monitor while I'm on both?
References (1)
- Product Information: FILSPARI® oral tablets, sparsentan oral tablets. Travere Therapeutics Inc, San Diego, CA, 2026. DailyMed
Keep reading about Relugolix
Keep reading about Sparsentan
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