Relugolix and Voriconazole: 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
Voriconazole
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.
Taking voriconazole (an antifungal) together with relugolix (a treatment for prostate cancer) can cause two things. First, both can affect your heart's rhythm by stretching out something called the QT interval, and combining them may add to that effect. Second, relugolix may cause your body to clear the voriconazole faster, so the antifungal might not work as well.
Please don't stop either medicine on your own. This is very manageable. Your care team can check your heart rhythm with an ECG, watch your blood minerals, and adjust your voriconazole dose if needed. Let your pharmacist or doctor know you take both.
Dual concern: additive QT prolongation plus a pharmacokinetic effect on voriconazole.
- QT/PD: Both agents can prolong the QT interval; combined use is additive. Risk is higher with congenital long QT, CHF, or electrolyte disturbances.
- PK: Relugolix is a CYP3A4 inducer; it may reduce voriconazole exposure (voriconazole is a CYP3A4/2C19/2C9 substrate), risking subtherapeutic antifungal levels and treatment failure.
- Evidence: theoretical; severity major; onset unspecified.
- Management: Correct electrolytes, obtain periodic ECGs and electrolytes, weigh benefit/risk of ADT, and adjust voriconazole dose while monitoring for lack of efficacy.
What happens
Increased risk of QT interval prolongation, reduced voriconazole exposure and an reduced efficacy of voriconazole
Interaction Deep Dive
Taking relugolix together with medications that prolong the QT interval, such as voriconazole, can produce additive QT interval effects. In patients who have congenital long QT syndrome, congestive heart failure, or recurrent electrolyte abnormalities, as well as those receiving drugs recognized to extend the QT interval, evaluate whether the advantages of androgen deprivation therapy, including relugolix, justify the possible hazards. Any electrolyte abnormalities should be corrected, and periodic ECG and electrolyte monitoring may be warranted1. Because relugolix and other CYP3A4 inducers can lower voriconazole exposure when given alongside it, the voriconazole dose should be modified and the patient watched for loss of efficacy during concurrent administration of voriconazole with CYP3A4 inducers 2.
Why it happens (mechanism)
Additive QT interval prolongation; induction of CYP3A4-mediated metabolism of voriconazole
How to manage this interaction
Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Here is what your care team typically does:
- Heart monitoring: They may check periodic ECGs to watch your heart rhythm.
- Blood work: They may check and correct electrolytes (like potassium and magnesium), which helps protect against rhythm problems.
- Antifungal dosing: Because relugolix may lower voriconazole levels, your voriconazole dose may need to be adjusted and individualized by your team, who will watch to make sure the infection stays controlled.
Tell your pharmacist or doctor if you feel faint, dizzy, or have a fluttering heartbeat, or if your infection seems to be worsening.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) In a drug interaction study, rifAMPin (a CYP3A4 inducer) at 600 mg once daily reduced the steady state Cmax and AUC(tau) of voriconazole (200 mg every 12 hours for 7 days) by an average of 93% and 96%, respectively, in healthy subjects. Increasing the voriconazole dose twofold to 400 mg every 12 hours does not restore adequate voriconazole exposure when it is given together with rifAMPin 2.
b) In a separate published study in healthy volunteers who received multiple oral doses of St. John's Wort (a CYP3A4 inducer) (300 mg LI 160 extract three times daily for 15 days) followed by a single 400 mg oral dose of voriconazole, a 59% decrease in mean voriconazole AUC(0 to inf) was seen. By contrast, giving single oral doses of St. John's Wort and voriconazole together produced no appreciable effect on voriconazole AUC(0 to inf). Prolonged use of St. John's Wort could result in decreased voriconazole exposure 2.
Common questions
Can I take Relugolix and Voriconazole together?
Combining voriconazole and relugolix can add to QT-prolongation risk and may lower voriconazole levels so it works less well; keep taking both as prescribed while your care team monitors your ECG, electrolytes, and antifungal dose. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Relugolix and Voriconazole 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 Voriconazole interaction managed?
Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Here is what your care team typically does: Heart monitoring: They may check periodic ECGs to watch your heart rhythm. Blood work: They may check and correct electrolytes (like potassium and magnesium), which helps protect against rhythm problems. Antifungal dosing: Because relugolix may lower voriconazole… 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 Voriconazole 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, 2024. DailyMed
- Product Information: VFEND(R) oral tablets, oral suspension, intravenous injection, voriconazole oral tablets, oral suspension, intravenous injection. Roerig (per FDA), New York, NY, 2025. DailyMed
Keep reading about Voriconazole
Keep reading about Relugolix
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