Relugolix and Sunitinib: 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
Sunitinib
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.
Both sunitinib (a cancer medicine) and relugolix (used mainly for prostate cancer) can affect your heart's electrical rhythm in the same way. Each one can stretch out a part of the heartbeat called the QT interval. When you take them together, that effect can add up and, in rare cases, lead to an abnormal heart rhythm.
The good news is this is a known, manageable concern. Your care team may check an ECG (a heart tracing) and your blood minerals like potassium and magnesium from time to time. Please keep taking both exactly as prescribed and talk with your pharmacist or doctor before changing anything.
Additive QT prolongation. Both agents independently prolong the QT interval; sunitinib is a known QT-prolonging tyrosine kinase inhibitor, and androgen deprivation from relugolix can also prolong QT. This is a pharmacodynamic (not metabolic) interaction, so no prodrug consideration applies.
- Direction: increased combined QT prolongation / torsades risk
- Evidence: theoretical; Severity: major; Onset: unspecified
- Higher-risk patients: congenital long QT, CHF, frequent electrolyte abnormalities
- Management: avoid combination when feasible; if required, avoid drugs causing hypokalemia/hypomagnesemia, correct electrolytes, and consider 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 or antagonists can itself lengthen the QT interval. In patients who have congenital long QT syndrome, congestive heart failure, or recurring electrolyte disturbances, as well as those receiving drugs known to prolong the QT interval, weigh whether the benefits of androgen deprivation therapy such as relugolix outweigh the potential risks 1. Where possible, do not use relugolix at the same time as agents that prolong the QT interval. Should coadministration be necessary, avoid medications that produce electrolyte abnormalities (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
This combination can add to the effect each drug has on your heart rhythm, but your care team can manage it.
- Keep taking both as prescribed unless your doctor tells you otherwise.
- Your team may do periodic ECGs and check electrolytes (potassium and magnesium), correcting any that are low.
- They may weigh whether the benefits outweigh the risks if you have a heart condition, heart failure, or frequent electrolyte problems.
- Tell your prescriber about any other QT-affecting medicines you take.
Report fainting, palpitations, or dizziness to your care team promptly.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) A study looking at male patients on androgen deprivation therapy (ADT) using individual case safety reports from VigiBase, the international pharmacovigilance database, identified 184 cases of acquired long-QT syndrome (aLQTS) and/or torsades de pointes (TdP; 11% of cases 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 happened without concurrent use of other agents known to raise TdP risk; nevertheless, use of 1 drug and of 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 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 patients had a median age of 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 primarily on ADT to treat prostate cancer, with some treated for prostatism and androgenic alopecia. Most were on ADT monotherapy (83%); 17% were on ADT combination therapy 3.
Common questions
Can I take Relugolix and Sunitinib together?
Taking sunitinib and relugolix together can add up their effect on your heart rhythm (QT interval), so your care team may monitor ECGs 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 Sunitinib 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 Sunitinib interaction managed?
This combination can add to the effect each drug has on your heart rhythm, but your care team can manage it. Keep taking both as prescribed unless your doctor tells you otherwise. Your team may do periodic ECGs and check electrolytes (potassium and magnesium), correcting any that are low. They may weigh whether the benefits outweigh the risks if you have a heart condition, heart failure, or freque… 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 Sunitinib 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 Sunitinib
Keep reading about Relugolix
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