Amitriptyline and Moricizine: 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
Moricizine
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. Amitriptyline (Elavil) is an older antidepressant, and moricizine is a heart rhythm medicine. Each one can slightly change the timing of your heartbeat. When you take them together, those effects can add up, which may raise the chance of an irregular or dangerous heartbeat.
I want to be honest that this concern is theoretical, meaning it is based on how these drugs work rather than a lot of real-world reports. The good news is that your care team can manage this well by keeping an eye on your heart, often with an EKG. Please don't stop either medicine on your own, just talk with your doctor or pharmacist.
Effect: Additive cardiac effects raising risk of QT prolongation, torsades de pointes, and cardiac arrest.
Mechanism: Pharmacodynamic additivity. Amitriptyline (TCA) has quinidine-like effects on cardiac conduction; moricizine (class I antiarrhythmic) also affects PR, QRS, and QTc intervals. Combined use potentiates conduction delay and repolarization prolongation. No prodrug considerations alter direction here.
- Direction: increased cardiotoxic effect
- Onset: unspecified
- Evidence: theoretical
- Magnitude: not quantified
Management: Monitor ECG (PR, QRS, QTc), electrolytes, and clinical signs of arrhythmia. Individualize dosing; consider closer follow-up or alternative therapy if warranted.
What happens
An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest)
Interaction Deep Dive
Because tricyclic antidepressants such as amitriptyline and class IA antiarrhythmics such as moricizine exert comparable effects on the heart, taking them together may heighten the potential for cardiotoxicity12. Consequently, observing the patient for indications of cardiac toxicity while amitriptyline and moricizine are given concurrently may be advisable.
Why it happens (mechanism)
Additive cardiac effects
How to manage this interaction
Keep taking both medicines as prescribed unless your doctor tells you otherwise. Here is how a care team usually handles this combination:
- They may check your heart rhythm with an EKG before and during treatment, watching your PR, QRS, and QTc intervals.
- Your doses may be adjusted and individualized by your care team.
- They may monitor you more closely, especially when starting or changing a dose.
What to do: Tell your pharmacist or doctor if you notice a fast, slow, or irregular heartbeat, palpitations, dizziness, fainting, or shortness of breath. Also let them know about any other medicines that affect heart rhythm.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) A higher rate of sudden death was seen in 6 of 53 patients with cardiac disease who received amitriptyline, versus 0 of 53 in the control group. The recommendation was to avoid amitriptyline in patients with underlying cardiac disease, except in cases where depression was debilitating and no other medications provided benefit 34.
b) In a placebo controlled study, imipramine 3.5 mg/kg was given daily to seven patients with severe depression, with doses titrated to reach therapeutic plasma concentrations. Two patients showed premature atrial depolarizations and premature ventricular depolarizations prior to therapy. One patient had 33 premature atrial depolarizations (PAD) and 30 premature ventricular depolarizations (PVD) per hour, which fell to 0.4 PAC and zero PVC per hour while on imipramine. The other patient had 12 PAD and 169 PVD per hour before treatment and 1.8 PAD and 28.1 PVD per hour while on imipramine. The authors further warned that the incidence of cardiotoxicity may rise if tricyclic antidepressants are given together with Type I antiarrhythmics. They also advised that quinidine and procainamide should not be used to treat the arrhythmias caused by a tricyclic overdose. The similarities among these agents may worsen the cardiotoxicity 1.
Common questions
Can I take Amitriptyline and Moricizine together?
Taking amitriptyline and moricizine together can add up to a higher risk of heart rhythm problems, so keep both as prescribed and let your care team monitor your heart, often with an EKG. Report any palpitations, dizziness, or fainting right away. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline and Moricizine 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 Moricizine interaction managed?
Keep taking both medicines as prescribed unless your doctor tells you otherwise. Here is how a care team usually handles this combination: They may check your heart rhythm with an EKG before and during treatment, watching your PR, QRS, and QTc intervals. Your doses may be adjusted and individualized by your care team. They may monitor you more closely, especially when starting or changing a dose.… 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 Moricizine 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 (4)
- Kantor SJ, Glassman AH, Bigger JT Jr. et al: The cardiac effects of therapeutic plasma concentrations of imipramine. Am J Psychiatry 1978; 135:534-538. PubMed
- Bigger JT, Giardina EG, Perel JM, et al: Cardiac antiarrhythmic effect of imipramine hydrochloride. N Engl J Med 1977; 296:206-208. PubMed
- Moir DC, Crooks J, Cornwell WB, et al: Cardiotoxicity of amitriptyline. Lancet 1972; 2:561-564. PubMed
- Coull DC, Crooks J, Dingwall-Fordyce I, et al: Amitriptyline and cardiac disease. Lancet 1970; 1:590-591. DOI
Keep reading about Amitriptyline
Keep reading about Moricizine
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
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