Drug Interaction Report

Amitriptyline and Ibutilide: Interaction Details

A pharmacist-reviewed analysis of the Amitriptyline and Ibutilide interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

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

Elavil
+

Ibutilide

Corvert
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Jul 2, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
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.

Of 525 documented Amitriptyline interactions, 421 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
At a glance + Theoretical Effects may be stronger
The Bottom Line
Amitriptyline and ibutilide can both prolong the QT interval, so using them together raises the risk of a dangerous heart rhythm and is generally not recommended. Ask your doctor or pharmacist about a safer option before making any changes.

Both of these medicines can affect your heart's rhythm in the same way. Amitriptyline (Elavil) is an antidepressant, and ibutilide (Corvert) is a heart rhythm drug. Each one can stretch out a part of your heartbeat called the QT interval. When you take them together, that effect can add up, which raises the risk of a dangerous, fast heartbeat.

This warning is based on how the drugs work rather than on studies of the two together, but it is taken seriously because heart rhythm problems can happen fast. The good news is your care team can manage this. Please talk with your doctor or pharmacist before making any changes, and never stop a medicine on your own.

Additive QT prolongation from co-administration of amitriptyline (a TCA) and ibutilide (a Class III antiarrhythmic). Both agents independently prolong the QTc interval, so combined use increases the risk of torsades de pointes and cardiac arrest.

  • Direction: additive pharmacodynamic effect (not PK-based); both drugs contribute to QTc prolongation.
  • Onset: rapid.
  • Evidence: theoretical; no formal interaction studies, but well-characterized class effect.
  • Management: concurrent use is not recommended. If unavoidable, obtain baseline and follow-up ECGs, correct electrolytes (K+, Mg2+), and monitor for QTc prolongation.
Onset
rapid
Evidence
theoretical
Severity
Major

What happens

An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest)

Interaction Deep Dive

QTc prolongation and/or torsades de pointes have been documented with every Class III antiarrhythmic agent, such as acecainide3, amiodarone4, azimilide5, bretylium6, ibutilide7, sematilide8, dofetilide9, and sotalol10. Although formal studies of drug interactions have not been conducted, giving Class III antiarrhythmics together with other agents recognized to lengthen the QTc interval, tricyclic antidepressants among them, is advised against211.

Why it happens (mechanism)

Additive QT prolongation

How to manage this interaction

Combining these two is generally not recommended because both prolong the QT interval. Here is what typically happens and what you can do:

  • Your care team may choose an alternative to one of the drugs so you are not on both at once.
  • If both are truly needed, your team may monitor you more closely with ECGs and check your potassium and magnesium levels.
  • Keep taking both medicines as prescribed unless your prescriber tells you otherwise.
  • Tell your pharmacist or doctor right away if you feel fainting, dizziness, or a fluttering or racing heartbeat.

Management is individual — confirm any change with your pharmacist or prescriber.

Literature reports

2 reports — tap to read

a) Among patients taking therapeutic doses of tricyclic antidepressants, documented electrocardiographic changes include a faster heart rate, lengthening of the PR interval, delays in intraventricular conduction, a longer corrected QT interval (QTc), and flattening of the T waves 1.

b) The simultaneous administration of Class III antiarrhythmic agents together with other medications capable of prolonging the QT interval, such as tricyclic antidepressants, is advised against. Dofetilide should be discontinued for a minimum of 2 days prior to starting any interacting agent. When concurrent use cannot be prevented, careful dosing along with telemetric monitoring is recommended 2.

Common questions

Can I take Amitriptyline and Ibutilide together?

Amitriptyline and ibutilide can both prolong the QT interval, so using them together raises the risk of a dangerous heart rhythm and is generally not recommended. Ask your doctor or pharmacist about a safer option before making any changes. Always confirm with your pharmacist or prescriber before making any change.

How serious is the Amitriptyline and Ibutilide interaction?

It is rated major. Potentially serious — often needs a change or close monitoring.

How quickly could this interaction happen?

The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.

How is the Amitriptyline and Ibutilide interaction managed?

Combining these two is generally not recommended because both prolong the QT interval. Here is what typically happens and what you can do: Your care team may choose an alternative to one of the drugs so you are not on both at once. If both are truly needed, your team may monitor you more closely with ECGs and check your potassium and magnesium levels. Keep taking both medicines as prescribed unles… 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 Ibutilide 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 (11)

  1. Marshall JB & Forker AD: Cardiovascular effects of tricyclic antidepressant drugs: therapeutic usage, overdose, and management of complications. Am Heart J 1982; 103:401-414. PubMed
  2. Yamreudeewong W, DeBisschop M, Martin LG, et al: Potentially significant drug interactions of class III antiarrhythmic drugs. Drug Safety 2003; 26(6):421-438. PubMed
  3. Chow MJ, Piergies AA, Bowsher DJ, et al: Torsade de pointes induced by N-acetylprocainamide. J Am Coll Cardiol 1984; 4:621-624. PubMed
  4. Faggiano P, Gardini A, D'Aloia A, et al: Torsade de pointes occurring early during oral amiodarone treatment. Int J Cardiol 1996; 55(2):205-208. DOI
  5. Corey AE, Agnew JR, Valentine SN, et al: Azimilide pharmacokinetics following intravenous and oral administration of a solution and capsule formulation. J Clin Pharmacol 1999; 39(12):1272-1276. PubMed
  6. Gilman AG, Goodman LS, Rall TW, et alGilman AG, Goodman LS, Rall TW, et al (Eds): The Pharmacological Basis of Therapeutics, 7th. Macmillan Publishing Co, New York, NY, 1985.
  7. Rodriguez I, Kilborn MJ, Liu XK, et al: Drug-induced QT prolongation in women during the menstrual cycle. JAMA 2001; 285(10):1322-1326. PubMed
  8. Singh BN: The coming of age of the class III antiarrhythmic principle: retrospective and future trends. Am J Cardiol 1996; 78(suppl):17-27. PubMed
  9. Allen MJ, Oliver SD, Newgreen MW, et al: Pharmacodynamic effect of continuous vs intermittent dosing of dofetilide on QT interval. Br J Clin Pharmacol 2002; 53:59-65.
  10. Marill KA & Runge T: Meta-analysis of the risk of torsades de pointes in patients treated with intravenous racemic sotalol. Acad Emerg Med 2001; 8(2):117-124. PubMed
  11. Product Information: Corvert(R), ibutilide fumarate injection. Pharmacia & Upjohn Company, Kalamazoo, MI, 2000. DailyMed
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Beyond drug–drug

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:

Amitriptyline + 1,4-butanediol Activated Charcoal American Hellebore Arsenic Beer Cesium Ephedra Gamma-hydroxybutyrate (ghb) + 288 more
Ibutilide + Activated Charcoal American Hellebore Arsenic Cesium Ephedra Grapefruit Sida Cordifolia Bitter Orange + 22 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.