Relugolix and Cisapride: 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
Cisapride
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.
Let's talk about taking relugolix (Orgovyx) together with cisapride (Propulsid). Both of these medicines can affect the timing of your heartbeat, something doctors call the QT interval. When two drugs that do this are combined, the effect can add up and raise the risk of a dangerous irregular heartbeat.
Because of this, using these two together is not recommended at all. The good news is this is easy for your care team to handle. Don't stop anything on your own, but do reach out to your pharmacist or doctor so they can review your medicines and pick a safer plan for you.
Interaction: Additive QT interval prolongation with concomitant relugolix and cisapride. This combination is classified as contraindicated.
- Mechanism: Additive pharmacodynamic prolongation of cardiac repolarization; both agents carry QT liability. Neither is a prodrug relevant here.
- Direction/effect: Increased risk of QT prolongation and serious ventricular arrhythmias (including torsades de pointes).
- Evidence: Theoretical; onset unspecified.
- Management: Avoid coadministration. If unavoidable, ECG and electrolyte (K+, Mg2+) monitoring would be warranted, but per labeling this pairing should not be used.
What happens
Increased risk of QT interval prolongation
Interaction Deep Dive
Giving cisapride together with medications known to prolong the QT interval is contraindicated, since combining them can heighten the likelihood of QT prolongation and serious ventricular arrhythmias1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
This drug pair is flagged as one to avoid combining because both can affect heart rhythm.
- Keep taking your medicines as prescribed for now, and do not stop either one on your own.
- Contact your pharmacist or prescriber promptly so they can review the combination.
- Your care team will typically choose an alternative medication for one of these, since using them together is not recommended.
- Mention any symptoms like fainting, dizziness, palpitations, or a fluttering heartbeat right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Relugolix and Cisapride together?
Relugolix and cisapride together can add up to raise the risk of a dangerous heart rhythm, and this combination should be avoided. Talk to your pharmacist or doctor so they can choose a safer option. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Relugolix and Cisapride interaction?
It is rated contraindicated. These should generally not be used together.
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 Cisapride interaction managed?
This drug pair is flagged as one to avoid combining because both can affect heart rhythm. Keep taking your medicines as prescribed for now, and do not stop either one on your own. Contact your pharmacist or prescriber promptly so they can review the combination. Your care team will typically choose an alternative medication for one of these, since using them together is not recommended. Mention an… 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 Cisapride 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 (1)
- Product Information: PROPULSID(R) oral tablets, oral suspension, cisapride oral tablets, oral suspension. Janssen Pharmaceutica, Titusville, NJ, 2000.
Keep reading about Relugolix
Keep reading about Cisapride
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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