Ceritinib 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
Ceritinib
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 of your medicines can affect the heart's electrical rhythm in the same way. Ceritinib (a cancer medicine) and relugolix (used for prostate cancer) can each slightly stretch out part of the heartbeat, something doctors call QT prolongation. When two medicines do this at once, the effect can add up and, rarely, lead to an irregular heartbeat.
This concern is based on how the drugs work rather than lots of real-world reports, but it is worth taking seriously. The good news is your care team can manage this by keeping an eye on your heart tracing (ECG) and your blood minerals like potassium and magnesium. Please don't stop either medicine on your own, just talk with your doctor or pharmacist.
Additive QT prolongation. Both ceritinib and relugolix are independently associated with QT interval prolongation; androgen deprivation from GnRH antagonists like relugolix can prolong QT, and ceritinib carries a known QTc risk. Concurrent use produces additive pharmacodynamic risk of QTc prolongation and, potentially, torsades de pointes. Evidence is theoretical/mechanistic; severity graded major.
- Direction: additive PD effect, not a metabolic (PK) interaction.
- Higher-risk patients: congenital long QT, CHF, electrolyte disturbances.
- Management: avoid combination when possible; if required, correct and avoid hypokalemia/hypomagnesemia, 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 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, refrain from using relugolix alongside QT prolonging agents. Should coadministration be necessary, steer clear of 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
Your care team weighs the benefit of treatment against this heart-rhythm risk, especially if you have a history of long QT, heart failure, or low blood minerals. Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise.
- Your team may check ECGs and blood electrolytes (potassium and magnesium) from time to time.
- They will try to correct and avoid low potassium or magnesium.
- In some cases they may consider an alternative if a safer option exists.
Tell your pharmacist or doctor about any fainting, dizziness, or palpitations, and mention any other QT-affecting medicines you take.
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 from the international pharmacovigilance database VigiBase, identifying 184 cases of acquired long-QT syndrome (aLQTS) and/or torsades de pointes (TdP; 11% fatal cases), along with 99 cases of sudden death linked to ADT. The majority of aLQTS/TdP cases (62%) and sudden death cases (88%) tied to ADT arose without exposure to other agents known to raise TdP risk; nevertheless, exposure to 1 drug and to 2 or more drugs carrying conditional, possible, or known TdP risk was reported in a portion of aLQTS/TdP (23% or 43%) and sudden death (18% and 22%) events. The agents classified 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 median patient age was approximately 76 years, and the median time to onset of aLQTS/TdP events was 170 days (range, 7 to 4884 days) while sudden death events had a median onset of 92 days (range, 0.25 to 4984 days). Patients were mainly receiving ADT to manage prostate cancer, with some 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 Ceritinib and Relugolix together?
Ceritinib and relugolix can each prolong the QT interval, so together the effect may add up. Keep taking both as prescribed and let your care team monitor your ECG and electrolytes. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ceritinib 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 Ceritinib and Relugolix interaction managed?
Your care team weighs the benefit of treatment against this heart-rhythm risk, especially if you have a history of long QT, heart failure, or low blood minerals. Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Your team may check ECGs and blood electrolytes (potassium and magnesium) from time to time. They will try to correct and avoid low potassium or… 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 Ceritinib 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 Ceritinib
Keep reading about Relugolix
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