Haloperidol 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
Haloperidol
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 your medicines can affect your heart's rhythm in the same way. Haloperidol is known to stretch out a part of the heartbeat called the QT interval, and relugolix (Orgovyx), which lowers testosterone, can do the same thing. When you take them together, those effects can add up and, in rare cases, lead to an irregular heartbeat.
The good news is this is a possible concern based on how the drugs work, not something guaranteed to happen. Your care team can manage it 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 doctor or pharmacist.
Effect: Additive QT-interval prolongation with increased torsades risk.
Mechanism: Pharmacodynamic additivity. Haloperidol prolongs QT via hERG/IKr blockade; androgen deprivation from relugolix (GnRH antagonist) can independently prolong QT. Neither drug is a prodrug; this is a PD, not PK, interaction.
Evidence: Theoretical. Onset: unspecified. Severity: major.
Management:
- Avoid concomitant use where feasible; weigh ADT benefit against risk.
- Higher caution in congenital long QT, CHF, or recurrent electrolyte disturbance.
- Correct and avoid hypokalemia/hypomagnesemia.
- 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 and antagonists can itself prolong 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 benefits 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, refrain from using drugs 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
Your care team can manage this safely. Here is what they typically do:
- Weigh the benefits of relugolix against heart-rhythm risk, especially if you have long QT syndrome, heart failure, or frequent electrolyte problems.
- Avoid combining QT-prolonging drugs when another option works, but sometimes both are needed.
- Watch your electrolytes (potassium and magnesium) and correct any lows.
- Check periodic ECGs and blood tests.
Keep taking both exactly as prescribed. Ask your pharmacist or doctor about ECG and electrolyte checks, and report any fainting, dizziness, or palpitations.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In an analysis of male patients undergoing androgen deprivation therapy (ADT) using individual case safety reports from VigiBase, the international pharmacovigilance database, 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 ADT-associated aLQTS/TdP cases (62%) and sudden death cases (88%) occurred without concurrent exposure to other agents known to raise TdP risk; nonetheless, 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 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 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 primarily receiving ADT for prostate cancer, with some treated for prostatism and androgenic alopecia. Most patients received ADT as monotherapy (83%), while 17% were on ADT combination therapy 3.
Common questions
Can I take Haloperidol and Relugolix together?
Haloperidol and relugolix can both prolong the QT interval, so together they may add up and raise the risk of a rhythm problem. Keep both as prescribed and ask your care team about ECG and electrolyte monitoring. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Haloperidol 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 Haloperidol and Relugolix interaction managed?
Your care team can manage this safely. Here is what they typically do: Weigh the benefits of relugolix against heart-rhythm risk, especially if you have long QT syndrome, heart failure, or frequent electrolyte problems. Avoid combining QT-prolonging drugs when another option works, but sometimes both are needed. Watch your electrolytes (potassium and magnesium) and correct any lows. Check periodic… 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 Haloperidol 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 Haloperidol
Keep reading about Relugolix
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