Relugolix and Itraconazole: 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
Itraconazole
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.
Let's talk about taking itraconazole (an antifungal, brand Sporanox) together with relugolix (Orgovyx, used for prostate cancer). Itraconazole blocks a 'pump' in your gut called P-gp that normally limits how much relugolix your body absorbs. When that pump is slowed down, more relugolix can build up in your system, which may lead to more side effects.
Both drugs can also affect the heart's electrical rhythm (the QT interval), and using them together may add to that effect. The good news is your care team knows how to manage this by spacing the doses, watching you more closely, and checking your heart tracing and blood work if needed. Please don't change anything on your own, just check in with your pharmacist or doctor.
Effect: Increased relugolix exposure plus additive QT prolongation risk.
Mechanism: Itraconazole inhibits P-gp-mediated efflux of relugolix (a P-gp substrate), raising relugolix AUC/Cmax. Both agents can prolong QT, giving an additive PD effect. Neither is a prodrug here.
Evidence: Theoretical. Severity: Major. Onset: Unspecified.
Management:
- Avoid concomitant use where possible.
- If unavoidable: give relugolix first, separate by at least 6 hours, monitor closely.
- Relugolix may be interrupted up to 2 weeks for a short itraconazole course; if held greater than 7 days, restart with 360 mg loading dose, then 120 mg daily.
- Correct electrolytes; consider periodic ECG and electrolyte monitoring, especially with cardiac risk factors.
What happens
Increased relugolix exposure and an increased risk of QT interval prolongation
Interaction Deep Dive
Do not combine relugolix (a P-gp substrate) with P-gp inhibitors, since doing so can raise relugolix exposure and thereby heighten the likelihood of adverse reactions. When coadministration cannot be avoided, give the relugolix-containing product first, allow a gap of no less than 6 hours between doses, and increase how often patients are monitored for adverse reactions12. Relugolix therapy may be paused for as long as 2 weeks to permit a brief course of a P-gp inhibitor, with relugolix resumed once the P-gp inhibitor has been stopped. Should relugolix be withheld for more than 7 days, restart it using a 360 mg loading dose on day one, followed by 120 mg once daily thereafter1. Giving relugolix together with medications that prolong the QT interval can produce additive QT interval effects. In patients who have congenital long QT syndrome, congestive heart failure, or recurrent electrolyte disturbances, as well as those receiving drugs recognized to prolong the QT interval, weigh whether the benefits of androgen deprivation therapy such as relugolix are greater than the possible risks. Electrolyte abnormalities should be corrected, and periodic ECG and electrolyte monitoring should be considered1.
Why it happens (mechanism)
Inhibition of P-gp-mediated efflux transport of relugolix; additive QT interval prolongation
How to manage this interaction
This combination can be managed by your care team. Keep taking both medications exactly as prescribed unless your prescriber tells you otherwise.
Your team may take steps such as:
- Avoiding the combination when another option works.
- If both are needed, taking your relugolix first and separating the two doses by at least 6 hours.
- Watching you more closely for side effects, and possibly checking your heart tracing (ECG) and blood mineral (electrolyte) levels.
- Sometimes pausing relugolix during a short course of the antifungal, with a specific plan to restart it.
Tell your pharmacist or doctor about any heart rhythm problems, fainting, dizziness, or palpitations, and mention all other medicines you take.
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 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 Itraconazole together?
Itraconazole can raise relugolix levels and add to heart-rhythm (QT) effects, so your care team may avoid the combination, space the doses, or monitor you more closely. Keep taking both as prescribed and check with your pharmacist or doctor before making changes. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Relugolix and Itraconazole 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 Itraconazole interaction managed?
This combination can be managed by your care team. Keep taking both medications exactly as prescribed unless your prescriber tells you otherwise. Your team may take steps such as: Avoiding the combination when another option works. If both are needed, taking your relugolix first and separating the two doses by at least 6 hours. Watching you more closely for side effects, and possibly checking your… 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Relugolix or Itraconazole 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 Itraconazole
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