Relugolix and Nafarelin: 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
Nafarelin
No brand names on record
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 relugolix (Orgovyx) and nafarelin work on the same hormone system, and lowering these hormones can gently affect the heart's electrical rhythm. This shows up on an EKG as something called QT prolongation. When two medicines that can do this are used together, the effect may add up, which in rare cases can lead to an irregular heartbeat.
I want to be clear: this concern is theoretical, meaning it's based on how these drugs work rather than lots of real-world cases. The risk matters most if you have a heart condition or low potassium or magnesium. The good news is your care team can manage this by checking your EKG and lab levels. Please don't change anything on your own, just talk with your doctor or pharmacist.
Effect: Additive risk of QT interval prolongation. Both agents suppress the GnRH axis; androgen deprivation itself is associated with QT prolongation, so combined use may produce additive QTc effects (pharmacodynamic, not PK).
- Direction: Additive QT prolongation (increased effect on cardiac repolarization).
- Evidence: Theoretical; mechanism-based.
- Onset: Unspecified.
- Higher-risk patients: congenital long QT syndrome, CHF, bradyarrhythmias, electrolyte disturbance (hypokalemia, hypomagnesemia), or concurrent QT-prolonging drugs.
- Management: Avoid combination when possible; weigh benefit of ADT vs risk. If used together, correct and maintain 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 effect on the QT interval is additive. The androgen deprivation produced by GnRH agonists and antagonists can itself lengthen the QT interval. In individuals 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 benefits of androgen deprivation therapy such as relugolix are greater than the possible risks1. Where feasible, do not use relugolix at the same time as agents that prolong QT. Should coadministration be necessary, refrain from using drugs that produce electrolyte disturbances (that is, hypokalemia or hypomagnesemia)2, correct any electrolyte disturbances, and consider periodically monitoring ECGs and electrolytes1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Because these drugs can each nudge your heart rhythm, your care team may take a few sensible steps:
- Check whether both are truly needed together, or whether an alternative fits better.
- Keep your potassium and magnesium in a healthy range, since low levels raise the risk.
- Do periodic EKGs and blood tests to monitor your heart and electrolytes.
Tell your pharmacist or doctor if you have a history of heart rhythm problems, heart failure, fainting, or take other medicines that affect the heartbeat. Report any palpitations, dizziness, or fainting promptly.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) A study assessed male patients undergoing androgen deprivation therapy (ADT) using individual case safety reports from VigiBase, the international pharmacovigilance database, and identified 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%) related to ADT occurred in the absence of other drugs recognized 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 the aLQTS/TdP events (23% or 43%) and sudden death events (18% and 22%). The drugs 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 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 receiving ADT chiefly for prostate cancer, with some treated for prostatism and androgenic alopecia. Most patients were on ADT monotherapy (83%); 17% were receiving ADT combination therapy 3.
Common questions
Can I take Relugolix and Nafarelin together?
Using relugolix and nafarelin together may add up their effect on your heart's QT rhythm, so your care team may avoid the combination or monitor your EKG and electrolytes. Keep taking both as prescribed and raise any heart history or fainting with your pharmacist or doctor. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Relugolix and Nafarelin 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 Nafarelin interaction managed?
Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Because these drugs can each nudge your heart rhythm, your care team may take a few sensible steps: Check whether both are truly needed together, or whether an alternative fits better. Keep your potassium and magnesium in a healthy range, since low levels raise the risk. Do periodic EKGs and blood tests to… 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 Nafarelin 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 Nafarelin
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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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