Ibutilide and Relugolix: 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
Ibutilide
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.
These two medicines can each affect your heart's electrical timing, something doctors measure as the QT interval. Relugolix (Orgovyx) lowers testosterone as part of prostate cancer treatment, and lowering testosterone can slightly stretch out that timing. Ibutilide (Corvert) is a heart rhythm medicine that is well known for stretching it too. Taken together, those effects can add up, which in rare cases can lead to a dangerous irregular heartbeat.
This concern is based on how the drugs work rather than lots of real-world reports, so please don't be alarmed. Your care team can manage this by checking your heart tracing (ECG) and your blood minerals, and by keeping those minerals in a healthy range.
Effect: Additive QT interval prolongation with increased risk of torsades de pointes.
Mechanism: Pharmacodynamic (additive), not pharmacokinetic. Ibutilide is a class III antiarrhythmic that prolongs repolarization; androgen deprivation from relugolix can independently prolong the QTc. Neither is a prodrug here; direction is additive QT effect.
- Severity: Major; Evidence: theoretical; Onset: unspecified.
- Management: Avoid concomitant use when possible. Weigh benefit of ADT in patients with congenital long QT, CHF, or frequent electrolyte disturbances. If combined, correct and maintain K+ and Mg2+, avoid other QT-prolonging or electrolyte-depleting agents, and perform periodic ECG and electrolyte monitoring.
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 and antagonists can itself lengthen the QT interval. In patients with 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 at the same time as QT prolonging agents. Should coadministration be necessary, refrain from using drugs that produce electrolyte disturbances (that is, hypokalemia or hypomagnesemia) 2, correct any electrolyte abnormalities, and consider periodic monitoring of ECGs and electrolytes 1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
Keep taking both exactly as prescribed unless your care team tells you otherwise. Because both can affect your heart rhythm, your team will decide whether the benefit outweighs the risk and may manage the combination closely.
- Expect periodic ECGs to check your heart's timing.
- Expect blood tests for minerals like potassium and magnesium, which your team will correct and keep in range.
- Tell your doctor if you have heart failure, a known long QT syndrome, or a history of low potassium or magnesium.
- Report fainting, dizziness, or a racing or irregular heartbeat right away.
Ask your pharmacist before starting any new medicine, since some also affect QT.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) A study examined male patients undergoing androgen deprivation therapy (ADT) using individual case safety reports in VigiBase, the international pharmacovigilance database. It identified 184 cases of acquired long-QT syndrome (aLQTS) and/or torsades de pointes (TdP; 11% of which were fatal), along with 99 cases of sudden death linked to ADT. The majority of ADT-associated aLQTS/TdP cases (62%) and sudden death cases (88%) arose without concurrent use of other drugs known to raise TdP risk; nonetheless, use of 1 drug and of 2 or more drugs carrying conditional, possible, or known TdP risk was noted in some aLQTS/TdP events (23% or 43%) and sudden death events (18% and 22%). The agents classified as ADTs included abiraterone, gonadotropin-releasing hormone agonists and antagonists, nonsteroidal androgen receptor inhibitors used for prostate cancer, and 5-alpha-reductase inhibitors used for androgenic alopecia and prostatism. Among the 10 ADTs assessed, 7 showed 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 roughly 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 mainly for prostate cancer, with some treated for prostatism and androgenic alopecia. Most patients were on ADT monotherapy (83%), while 17% were receiving ADT combination therapy 3.
Common questions
Can I take Ibutilide and Relugolix together?
Relugolix and ibutilide can both prolong the QT interval, and combining them adds to that risk, so your care team may avoid the combination or monitor your ECG and electrolytes closely. Keep taking both as prescribed and report any fainting or irregular heartbeat. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ibutilide and Relugolix 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 Ibutilide and Relugolix interaction managed?
Keep taking both exactly as prescribed unless your care team tells you otherwise. Because both can affect your heart rhythm, your team will decide whether the benefit outweighs the risk and may manage the combination closely. Expect periodic ECGs to check your heart's timing. Expect blood tests for minerals like potassium and magnesium, which your team will correct and keep in range. Tell your doc… 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 Ibutilide or Relugolix 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 Relugolix
Keep reading about Ibutilide
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
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