Relugolix and Delamanid: 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
Delamanid
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 of these medicines can affect your heart's rhythm. Relugolix (Orgovyx) lowers testosterone to treat prostate cancer, and that hormone change can slightly stretch out a part of your heartbeat called the QT interval. Delamanid, a medicine for tuberculosis, can do the same thing. When you take them together, those effects can add up and raise the small risk of an irregular heartbeat.
The good news is that this is a possible risk your care team knows how to watch for. They may check your heart with an ECG and keep an eye on your blood minerals like potassium and magnesium. Don't stop either medicine on your own, just talk with your doctor or pharmacist so they can keep you safe.
Effect: Additive QT interval prolongation with combined relugolix and delamanid.
Mechanism: Pharmacodynamic (additive), not a metabolic interaction. Androgen deprivation from relugolix can prolong QT; delamanid is an independent QT-prolonging agent. Neither is a prodrug relevant here.
- Severity/evidence: Major severity, theoretical substantiation.
- Onset: Unspecified.
- Management: Avoid concomitant use when feasible. Weigh benefit of ADT in patients with congenital long QT, CHF, or electrolyte disturbances. If used together, avoid agents causing hypokalemia/hypomagnesemia, correct electrolytes, 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 outweigh the possible risks1. Where feasible, do not use relugolix concurrently with QT prolonging agents. Should coadministration be necessary, steer clear of drugs that produce electrolyte abnormalities (that is, hypokalemia or hypomagnesemia)2, correct any electrolyte abnormalities, and consider periodic ECG and electrolyte monitoring1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
Your care team can manage this combination safely with some monitoring.
- Keep taking both medicines as prescribed unless your doctor tells you otherwise.
- Your team may order periodic ECGs to check your heart rhythm and blood tests for potassium and magnesium.
- They will try to avoid other things that lower these minerals and will correct any imbalances.
- If you have a heart condition, heart failure, or a family history of long QT syndrome, mention it.
Tell your pharmacist or prescriber right away if you feel fainting, dizziness, or a fluttering or pounding heartbeat.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) A study assessing 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 ADT-associated aLQTS/TdP cases (62%) and sudden death cases (88%) arose without concurrent use of other agents known to raise TdP risk; nevertheless, use of 1 drug and 2 or more drugs carrying conditional, possible, or known TdP risk was noted 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 demonstrated 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 on ADT chiefly to manage prostate cancer, with some treated for prostatism and androgenic alopecia. The majority of patients received ADT monotherapy (83%); 17% were on ADT combination therapy 3.
Common questions
Can I take Relugolix and Delamanid together?
Relugolix and delamanid can both prolong the QT interval, and together the effect may add up. It is a theoretical but serious concern, so let your care team monitor your heart rhythm and electrolytes and report any dizziness or palpitations. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Relugolix and Delamanid 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 Delamanid interaction managed?
Your care team can manage this combination safely with some monitoring. Keep taking both medicines as prescribed unless your doctor tells you otherwise. Your team may order periodic ECGs to check your heart rhythm and blood tests for potassium and magnesium. They will try to avoid other things that lower these minerals and will correct any imbalances. If you have a heart condition, heart failure,… 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 Delamanid 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 Delamanid
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