Relugolix and Telaprevir: 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
Telaprevir
No brand names on recordRelugolix
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 moved out of your body with the help of a pump in your gut called P-gp. Telaprevir can block that pump, which means more relugolix can build up in your blood. Higher levels can mean more side effects.
On top of that, both of these medicines can affect your heart's rhythm (a change on the ECG called QT prolongation). Taken together, that effect may add up. The good news is this is a well-understood, manageable situation. Please don't stop or change either medicine on your own, just talk with your pharmacist or doctor so they can guide the timing and keep an eye on things.
Mechanism: Telaprevir inhibits P-gp-mediated efflux of relugolix (a P-gp substrate), increasing relugolix exposure. Both agents also carry QT-prolonging potential, giving additive PD risk. Neither is a prodrug here, so effect is increased relugolix levels plus additive QTc effect.
- Direction: increased relugolix AUC/Cmax; increased QT prolongation risk
- Evidence: theoretical; Severity: major; onset unspecified
- Management: avoid combination if possible. If unavoidable, give relugolix first, separate by at least 6 hours, and monitor for adverse reactions. 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.
- Correct electrolytes; consider periodic ECG and electrolyte monitoring, especially with long QT syndrome, CHF, or other QT drugs.
What happens
Increased relugolix exposure and an increased risk of QT interval prolongation
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. When such combined use cannot be avoided, give the relugolix-containing medication first, allow a gap of at least 6 hours between doses, and increase how often you monitor for adverse reactions 12. Relugolix therapy may be paused for as long as 2 weeks to allow a brief course of P-gp inhibitor treatment, with relugolix resumed once the P-gp inhibitor has been stopped. Should relugolix be withheld for more than 7 days, reinitiate it using a 360 mg loading dose on day one, followed by 120 mg once daily thereafter 1. When relugolix is given alongside drugs that prolong the QT interval, the effects on the QT interval may be additive. In patients who have congenital long QT syndrome, congestive heart failure, or recurrent electrolyte disturbances, as well as those receiving medications recognized to prolong the QT interval, weigh whether the advantages of androgen deprivation therapy such as relugolix are greater than the possible risks. Correct any electrolyte disturbances and consider carrying out periodic ECG and electrolyte monitoring 1.
Why it happens (mechanism)
Inhibition of P-gp-mediated efflux transport of relugolix; additive QT interval prolongation
How to manage this interaction
What your care team may do:
- Try to avoid using these two together when possible, or choose an alternative.
- If they must be combined, take your relugolix dose first and separate the two by at least 6 hours.
- Watch you more closely for side effects, and possibly check ECGs and electrolyte levels (like potassium and magnesium) periodically.
- In some cases relugolix may be paused briefly during a short course of the other drug, then restarted as directed by your prescriber.
What you should do: keep taking both exactly as prescribed and don't change anything on your own. Ask your pharmacist or doctor about the best timing and whether any heart or electrolyte checks are needed.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) When relugolix (a P-gp substrate) was given together with erythromycin (a P-gp and CYP3A inhibitor), the AUC and Cmax of relugolix rose by 3.5-fold and 2.9-fold, respectively 1.
Common questions
Can I take Relugolix and Telaprevir together?
Telaprevir can raise relugolix levels and both can affect heart rhythm, so this pairing is best avoided or carefully managed with separated dosing and monitoring. Talk with your pharmacist or doctor before combining them. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Relugolix and Telaprevir 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 Telaprevir interaction managed?
What your care team may do: Try to avoid using these two together when possible, or choose an alternative. If they must be combined, take your relugolix dose first and separate the two by at least 6 hours. Watch you more closely for side effects, and possibly check ECGs and electrolyte levels (like potassium and magnesium) periodically. In some cases relugolix may be paused briefly during a short… 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 Telaprevir 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 Telaprevir
Keep reading about Relugolix
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