Amitriptyline and Chlorpromazine: 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
Chlorpromazine
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 amitriptyline and chlorpromazine can slightly affect your heart's electrical rhythm, causing something called QT prolongation. When you take them together, that effect can add up, which may raise the risk of an irregular heartbeat.
The good news is this is mostly a theoretical concern based on how these drugs work, not something that happens to everyone. Many people take medicines like these safely. Please keep taking both as prescribed, and check in with your doctor or pharmacist. They can watch your heart rhythm and adjust things if needed. Let them know right away if you feel fainting, dizziness, or a fluttering heartbeat.
Effect: Additive risk of QT interval prolongation when amitriptyline and chlorpromazine are used together.
Mechanism: Both agents independently prolong cardiac repolarization; combined use produces additive QT effects (pharmacodynamic, not PK based). Neither is a relevant prodrug here.
- Severity: Major
- Evidence: Theoretical
- Onset: Unspecified
Management: Use with caution. Consider baseline and follow-up ECG, correct electrolytes (K+, Mg2+), review other QT-prolonging agents, and assess cardiac risk factors. Dosing may need to be individualized and patients monitored more closely. Counsel on syncope, palpitations, and presyncope.
What happens
An increased risk of QT interval prolongation
Interaction Deep Dive
Concurrent administration of amitriptyline and chlorproMAZINE warrants caution, as these agents may produce additive QT interval effects and heighten the risk of serious cardiovascular events1.
Why it happens (mechanism)
Additive effects on the QT interval
How to manage this interaction
Your care team can manage this combination safely with a few sensible steps:
- Keep taking both medications exactly as prescribed unless your prescriber tells you otherwise.
- Your doctor may check your heart rhythm (an ECG) and your blood levels of potassium and magnesium, since these affect heart rhythm.
- Doses may need to be adjusted and individualized by your care team, and they may monitor you more closely.
Tell your pharmacist or doctor about any other medicines you take, and report symptoms like fainting, dizziness, or a pounding or irregular heartbeat right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Amitriptyline and Chlorpromazine together?
Taking amitriptyline and chlorpromazine together can add up to a higher risk of a heart rhythm change (QT prolongation), so use them together only under your care team's guidance and monitoring. Keep taking both as prescribed and report fainting, dizziness, or an irregular heartbeat. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline and Chlorpromazine 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 Amitriptyline and Chlorpromazine interaction managed?
Your care team can manage this combination safely with a few sensible steps: Keep taking both medications exactly as prescribed unless your prescriber tells you otherwise. Your doctor may check your heart rhythm (an ECG) and your blood levels of potassium and magnesium, since these affect heart rhythm. Doses may need to be adjusted and individualized by your care team, and they may monitor you mor… 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 Chlorpromazine 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: amitriptyline HCl oral tablet, amitriptyline HCl oral tablet. RemedyRepack Inc. (per DailyMed), Indiana, PA, 2010. DailyMed
Keep reading about Amitriptyline
Keep reading about Chlorpromazine
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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