Relugolix and Triclabendazole: 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
Triclabendazole
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.
These two medicines can each affect your heart's rhythm. Triclabendazole (Egaten) is a short course used to treat a parasite infection, and relugolix (Orgovyx) lowers testosterone to treat prostate cancer. Both can slightly stretch out the heart's electrical cycle, something doctors call QT prolongation. When taken together, that effect can add up and, in rare cases, lead to an irregular heartbeat.
The good news is this is a theoretical concern, and your care team can manage it easily. They may check an ECG and your blood minerals (like potassium and magnesium) and keep those in a healthy range. Keep taking both as prescribed and just talk with your pharmacist or doctor.
Effect: Additive risk of QT-interval prolongation with coadministration of relugolix and triclabendazole. Neither is a prodrug; this is a pharmacodynamic (additive), not pharmacokinetic, interaction.
- Direction: Both agents independently prolong QT; combined use increases torsadogenic risk.
- Onset: Unspecified. Evidence: Theoretical.
- Higher-risk patients: Congenital long QT, CHF, electrolyte disturbances, or other QT-prolonging drugs.
Management: Avoid concomitant use when possible. If required, correct and maintain normal potassium/magnesium, avoid additional agents causing electrolyte loss, and consider periodic ECG and electrolyte monitoring. Weigh benefits of androgen deprivation against risk.
What happens
Increased risk of QT interval prolongation
Interaction Deep Dive
When relugolix is given alongside 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 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 potential risks1. Where feasible, do not use relugolix together with 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 periodic monitoring of ECGs and electrolytes1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
This is manageable with a few precautions. Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise.
- Your care team may avoid using these together when another option exists.
- If you do take both, they may check an ECG and your electrolytes (potassium and magnesium) and correct any low levels.
- Tell them about any other QT-affecting medicines, or conditions like heart failure or a family history of heart rhythm problems.
- Report symptoms such as fainting, palpitations, or dizziness right away.
Ask your pharmacist or doctor if you have questions about timing or monitoring.
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 on androgen deprivation therapy (ADT) using individual case safety reports from the international pharmacovigilance database VigiBase, investigators 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%) associated with ADT arose without exposure to other agents recognized to raise TdP risk; nevertheless, exposure to 1 drug and to 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 receiving ADT 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 Triclabendazole together?
Both triclabendazole and relugolix can prolong the QT interval, so together they raise the risk of an irregular heartbeat; your care team can manage this by checking your ECG and electrolytes and avoiding the combination when possible. Keep taking both as prescribed and flag any fainting or palpitations. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Relugolix and Triclabendazole 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 Triclabendazole interaction managed?
This is manageable with a few precautions. Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Your care team may avoid using these together when another option exists. If you do take both, they may check an ECG and your electrolytes (potassium and magnesium) and correct any low levels. Tell them about any other QT-affecting medicines, or conditions like he… 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 Triclabendazole 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 Triclabendazole
Keep reading about Relugolix
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