Antiarrhythmic Medicines for Fast Heart Rates

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Antiarrhythmic Medicines for Fast Heart Rates


Generic NameBrand Name

How It Works

Antiarrhythmic medicines work in various ways to return the heart to its normal rhythm. These medicines stabilize heart rhythm. One way is by decreasing abnormal firing of the heart's electrical system that causes the heart to beat too fast. Another way is by slowing the electrical conduction through abnormal pathways. Some antiarrhythmics also slow the heart rate by reducing the number of impulses that can pass through the atrioventricular (AV) node (amiodarone, sotalol).

Why It Is Used

Antiarrhythmic medicines are used to change an abnormal heart rhythm to a regular rhythm and to prevent an abnormal heart rhythm.

How Well It Works

Antiarrhythmic medicines can effectively control or prevent abnormal heart rhythms.1 There are many different types of antiarrhythmic medicines. You may need to try different medicines to see which one works best for you.

Side Effects

Some antiarrhythmic medicines may increase the risk of developing a more rapid, abnormal heart rate problem (ventricular tachycardia or ventricular fibrillation), especially for those people who have a poorly functioning left ventricle. Close monitoring while taking these medicines is important.

Side effects of antiarrhythmics include:

  • Chest pain.
  • Slow heartbeat.
  • Palpitations.
  • Fatigue.
  • Headache.
  • Dizziness.
  • Nausea and vomiting.
  • Unusual taste in the mouth.
  • Stomach pain.
  • Constipation or diarrhea.
  • Difficulty breathing.
  • Rash.
  • Vision problems.
  • Urinary retention in men.
  • Thyroid disorders.
  • Blue tinge to the skin (with amiodarone).

Amiodarone (Cordarone) may cause serious side effects that can lead to death, including lung damage, liver damage, and more severe heartbeat problems. Amiodarone is typically used for people who have severe symptoms when other medicines have failed.

If you take amiodarone and simvastatin, which is a cholesterol medicine, you may have a higher risk of a serious muscle problem called rhabdomyolysis. Simvastatin medicines include Zocor.

Talk to your doctor if you have any side effects or any concerns about taking amiodarone.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

You should learn to take your pulse if you are taking an antiarrhythmic medicine. Let your doctor know if your heart rhythm becomes too slow (less than 50 beats per minute) or irregular while you are taking an antiarrhythmic medicine.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.



  1. Drugs for cardiac arrhythmias (2007). Treatment Guidelines From The Medical Letter, 5(58): 51–58.


By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Primary Medical Reviewer Donald Sproule, MD, CM, CCFP, FCFP - Family Medicine
Specialist Medical Reviewer John M. Miller, MD - Electrophysiology
Last Revised November 26, 2010

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.