Vorinostat 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
Vorinostat
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 timing of your heartbeat. Doctors call this QT prolongation. Vorinostat (Zolinza) is a cancer medicine that can lengthen this timing, and relugolix (Orgovyx), which lowers testosterone to treat prostate cancer, can do the same. When you take both, those effects can add together, and in rare cases that can lead to an irregular heartbeat.
The good news is that this is a known, manageable concern. Your care team can check your heart rhythm with an ECG and keep an eye on blood minerals like potassium and magnesium. Please don't stop either medicine on your own. Just let your doctor or pharmacist know you take both.
Effect: Additive risk of QT interval prolongation with concurrent vorinostat and relugolix.
Mechanism: Pharmacodynamic (additive), not a metabolic interaction. Vorinostat is an intrinsic QT-prolonging agent; androgen deprivation from relugolix can also prolong the QT interval.
- Direction: Additive PD effect increasing torsadogenic risk.
- Onset: Unspecified.
- Evidence: Theoretical.
- Severity: Major.
Management: Avoid combination when feasible. If required, correct and avoid electrolyte disturbances (hypokalemia, hypomagnesemia), and consider periodic ECG and electrolyte monitoring. Weigh benefit of ADT against risk in patients with congenital long QT, CHF, or recurrent electrolyte abnormalities.
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. GnRH agonists and antagonists can lengthen the QT interval through androgen deprivation. 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 hazards1. Where feasible, do not combine relugolix with 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 think about periodic monitoring of 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 doctor tells you otherwise. Here is how a care team usually handles this:
- Weigh the benefit: Your team decides if the cancer benefit of relugolix outweighs the heart risk, especially if you have a known QT condition, heart failure, or mineral imbalances.
- Monitoring: They may check ECGs and blood electrolytes (potassium, magnesium) from time to time.
- Prevent triggers: They will correct any low potassium or magnesium and avoid other things that cause them.
Tell your pharmacist or prescriber about all your medicines, and report fainting, dizziness, or palpitations right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) An analysis of male patients on androgen deprivation therapy (ADT), drawing on individual case safety reports from the international pharmacovigilance database VigiBase, identified 184 cases of acquired long-QT syndrome (aLQTS) and/or torsades de pointes (TdP; 11% of which were fatal), 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 in the absence of 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 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. The patients were receiving ADT chiefly for 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 Vorinostat and Relugolix together?
Using vorinostat and relugolix together can add up to prolong the QT interval and raise the risk of a dangerous heart rhythm, so your care team may monitor ECGs and electrolytes and correct any imbalances. Keep taking both as prescribed and report fainting or palpitations. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Vorinostat 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 Vorinostat and Relugolix interaction managed?
Keep taking both medicines exactly as prescribed unless your doctor tells you otherwise. Here is how a care team usually handles this: Weigh the benefit: Your team decides if the cancer benefit of relugolix outweighs the heart risk, especially if you have a known QT condition, heart failure, or mineral imbalances. Monitoring: They may check ECGs and blood electrolytes (potassium, magnesium) from t… 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 Vorinostat 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 Vorinostat
Keep reading about Relugolix
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