Relugolix and Fexinidazole: 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
Fexinidazole
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.
Both of these medicines can affect your heart's electrical timing, something doctors call the QT interval. Fexinidazole (an infection medicine) and relugolix (Orgovyx, used in prostate cancer) can each stretch out that timing a little. When you take them together, those effects can add up, which in rare cases can lead to an abnormal heartbeat.
The good news is that this concern is theoretical, meaning it is based on how the drugs work rather than reported problems. Your care team can manage it well, often by checking your heart tracing (ECG) and blood minerals like potassium and magnesium. Please don't stop either medicine on your own. Just talk with your pharmacist or doctor about the best plan.
Effect: Additive QT interval prolongation (pharmacodynamic, not PK based). Both agents independently prolong QT; androgen deprivation from relugolix contributes to QT prolongation, and fexinidazole is a recognized QT prolonging agent.
- Direction: Additive increase in QT prolongation risk / torsades risk.
- Onset: Unspecified.
- Evidence: Theoretical; severity rated major.
- Higher-risk patients: Congenital long QT, CHF, frequent electrolyte disturbances.
Management: Avoid concomitant use where possible. If required, correct and maintain normal potassium/magnesium, avoid agents causing electrolyte depletion, and perform periodic ECG and electrolyte monitoring. Weigh benefit of ADT against arrhythmia risk.
What happens
Increased risk of QT interval prolongation
Interaction Deep Dive
When relugolix is given together with medications that prolong the QT interval, the effects on the QT interval are additive. The androgen deprivation produced by GnRH agonists or antagonists can itself lengthen the QT interval. 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 advantages of androgen deprivation therapy such as relugolix are greater than the possible risks 1. Where feasible, do not use relugolix alongside QT prolonging agents. Should coadministration be necessary, steer clear of drugs that produce electrolyte disturbances (namely, hypokalemia or hypomagnesemia) 2, correct any electrolyte abnormalities, and consider periodic ECG and electrolyte monitoring 1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
Your care team can keep this manageable. Here is what they typically consider:
- Weighing options: They may decide whether both drugs are truly needed together, especially if you have a heart-rhythm condition, heart failure, or a history of low blood minerals.
- Monitoring: They may order periodic heart tracings (ECGs) and blood tests for potassium and magnesium.
- Correcting minerals: They will keep your potassium and magnesium in a healthy range and avoid anything that lowers them.
What you should do: Keep taking both exactly as prescribed unless told otherwise. Report any fainting, dizziness, or palpitations right away, and ask your pharmacist or doctor before adding new medicines.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In an investigation of male patients receiving androgen deprivation therapy (ADT) using individual case safety reports from the international pharmacovigilance database VigiBase, investigators identified 184 cases of acquired long-QT syndrome (aLQTS) and/or torsades de pointes (TdP; 11% of cases were fatal), along with 99 cases of sudden death linked to ADT. The majority of aLQTS/TdP cases (62%) and sudden death cases (88%) related to ADT arose without concurrent use of other agents known to elevate TdP risk; nevertheless, use of 1 drug and 2 or more drugs carrying conditional, possible, or known TdP risk was documented in a portion of aLQTS/TdP (23% or 43%) and sudden death (18% and 22%) events. The agents regarded as ADTs included abiraterone, gonadotropin-releasing hormone agonists and antagonists, nonsteroidal androgen receptor inhibitors indicated for prostate cancer, and 5-alpha-reductase inhibitors indicated for androgenic alopecia and prostatism. Among the 10 ADTs assessed, 7 demonstrated a disproportional association (reporting odds ratio, 1.4 to 4.7) with aLQTS, TdP, or sudden death, namely leuprorelin, goserelin, triptorelin, degarelix, bicalutamide, finasteride, and dutasteride. The median patient age was approximately 76 years, and the median time to onset was 170 days (range, 7 to 4884 days) for aLQTS/TdP events and 92 days (range, 0.25 to 4984 days) for sudden death events. Patients were taking ADT chiefly for prostate cancer, with a subset treated for prostatism and androgenic alopecia. The majority of patients were on ADT monotherapy (83%); 17% were receiving ADT combination therapy 3.
Common questions
Can I take Relugolix and Fexinidazole together?
Taking fexinidazole and relugolix together can add up their effects on your heart's QT interval, so your care team may monitor your ECG and blood minerals. Keep taking both as prescribed and report any fainting or palpitations. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Relugolix and Fexinidazole 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 Fexinidazole interaction managed?
Your care team can keep this manageable. Here is what they typically consider: Weighing options: They may decide whether both drugs are truly needed together, especially if you have a heart-rhythm condition, heart failure, or a history of low blood minerals. Monitoring: They may order periodic heart tracings (ECGs) and blood tests for potassium and magnesium. Correcting minerals: They will keep yo… 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 Fexinidazole 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 (3)
- Product Information: ORGOVYX oral tablets, relugolix oral tablets. Sumitomo Pharma America, Inc (per FDA), Marlborough, MA, 2025. DailyMed
- Lyon AR, Lopez-Fernandez T, Couch LS, et al: 2022 ESC guidelines on cardio-oncology developed in collaboration with the European Hematology Association (EHA), the European Society for Therapeutic Radiology and Oncology (ESTRO) and the International Cardio-Oncology Society (IC-OS). Eur Heart J 2022; 43(41):4229-4361.
- Salem JE, Yang T, Moslehi JJ, et al: Androgenic effects on ventricular repolarization: a translational study from the international pharmacovigilance database to iPSC-cardiomyocytes. Circulation 2019; 140(13):1070-1080. PubMed
Keep reading about Fexinidazole
Keep reading about Relugolix
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