Amitriptyline 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
Amitriptyline
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.
These two medicines are not meant to be taken together. Amitriptyline (Elavil) is an older antidepressant, and cisapride (Propulsid) is a stomach medicine. Both can affect the electrical timing of your heartbeat, something doctors call the QT interval. When you take them together, that effect can add up and raise the risk of a dangerous irregular heartbeat.
The good news is this is easy to avoid. If you have been prescribed both, don't stop anything on your own, but do reach out to your pharmacist or doctor soon. They can pick a safer option so your heart stays protected.
Interaction: Additive QT interval prolongation with combined amitriptyline and cisapride, increasing risk of serious ventricular arrhythmias (including torsades de pointes).
- Mechanism: Both agents independently prolong cardiac repolarization; effect is additive (pharmacodynamic, not a prodrug issue).
- Direction/magnitude: Increased QT prolongation risk; magnitude not quantified.
- Evidence: Theoretical, but severity rating is contraindicated.
- Onset: Unspecified.
- Management: Avoid concomitant use. If unavoidable, ECG and electrolyte monitoring (K+, Mg2+) and selection of an alternative agent are warranted.
What happens
Increased risk of QT interval prolongation
Interaction Deep Dive
Giving cisapride together with agents that prolong the QT interval is contraindicated, because such combined administration 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 combination is listed as contraindicated, meaning it is generally meant to be avoided rather than dose-adjusted.
- Keep taking both as prescribed for now, but contact your pharmacist or prescriber promptly.
- Your care team will likely choose an alternative to one of these medicines so both effects on the heart's rhythm don't stack up.
- Tell your team about any dizziness, fainting, palpitations, or a racing or irregular heartbeat right away.
- Mention any history of heart rhythm problems or low potassium or magnesium levels.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Amitriptyline and Cisapride together?
Amitriptyline and cisapride are considered a contraindicated combination because both can prolong the QT interval, raising the risk of a dangerous heart rhythm. Don't stop either on your own, but contact your pharmacist or doctor soon so they can switch you to a safer option. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline 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 Amitriptyline and Cisapride interaction managed?
This combination is listed as contraindicated, meaning it is generally meant to be avoided rather than dose-adjusted. Keep taking both as prescribed for now, but contact your pharmacist or prescriber promptly. Your care team will likely choose an alternative to one of these medicines so both effects on the heart's rhythm don't stack up. Tell your team about any dizziness, fainting, palpitations, o… 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Amitriptyline 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 Amitriptyline
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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