Amiodarone; Dronedarone/Carbamazepine; Phenobarbital; Phenytoin Interactions

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

Carbamazepine, phenobarbital, phenytoin and primidone may speed up how quickly your liver processes amiodarone and dronedarone. Amiodarone may speed up how quickly your liver processes phenytoin.

What might happen:

The amount of amiodarone and dronedarone in your blood may decrease and it may not work as well. If you are taking amiodarone and phenytoin, the amount of phenytoin in your blood may increase and cause side effects.

What you should do about this interaction:

Make sure your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. Let your doctor know right away if you experience and irregular or unusually fast heartbeat. If you are taking phenytoin, let your healthcare professional know if you have any symptoms of phenytoin toxicity (nausea, vomiting, confusion, dizziness, changes in vision, loss of coordination, or drowsiness). Your doctor may need to change the dosage of your phenytoin.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.

  • 1.Cordarone (amiodarone hydrochloride) US prescribing information. Wyeth Pharmaceuticals October, 2018.
  • 2.Multaq (dronedarone) US prescribing information. Sanofi-Aventis U.S. LLC January, 2014.
  • 3.Leite SA, Leite PJ, Rocha GA, Routledge PA, Bittencourt PR. Carbamazepine kinetics in cardiac patients before and during amiodarone. Arq Neuropsiquiatr 1994 Jun;52(2):210-5.
  • 4.Nolan PE Jr, Marcus FI, Karol MD, Hoyer GL, Gear K. Effect of phenytoin on the clinical pharmacokinetics of amiodarone. J Clin Pharmacol 1990 Dec; 30(12):1112-9.
  • 5.Nolan PE Jr, Marcus FI, Hoyer GL, Bliss M, Gear K. Pharmacokinetic interaction between intravenous phenytoin and amiodarone in healthy volunteers. Clin Pharmacol Ther 1989 Jul;46(1):43-50.
  • 6.Nolan PE Jr, Erstad BL, Hoyer GL, Bliss M, Gear K, Marcus FI. Steady-state interaction between amiodarone and phenytoin in normal subjects. Am J Cardiol 1990 May 15;65(18):1252-7.

Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, except as may be authorized by the applicable terms of use.

CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.