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Heart Disease Health Center

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Antiarrhythmic Medicines for Fast Heart Rates


Generic Name Brand Name
amiodarone Cordarone, Pacerone
disopyramide Norpace
dofetilide Tikosyn
dronedarone Multaq
flecainide Tambocor
propafenone Rythmol
sotalol Betapace

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 raise your risk of having a dangerous arrhythmia such as ventricular tachycardia or ventricular fibrillation. Your doctor will check you closely while you take these medicines. The risk of side effects might be greater if you have severe heart disease.

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

  • Usually the benefits of the medicine are more important than any minor side effects.
  • Side effects may go away after you take the medicine for a while.
  • If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.

Call 911 or other emergency services right away if you have:

Heart symptoms such as:

  • New or worse dizziness or lightheadedness.
  • Severe heart palpitations.
  • Severe weakness.

Severe allergy symptoms such as:

Antiarrhythmic medicines can cause less serious side effects that may go away after taking the medicine for a while. Call your doctor if these side effects continue or if they bother you a lot.


Call your doctor if you have any side effects from amiodarone. Side effects may include:

  • Cough or trouble breathing.
  • Dizziness, lightheadedness, or fainting.
  • Trembling or shaking.
  • Weakness in the arms or legs.
  • Blurry vision or other vision changes.


Call your doctor right away if you have:

  • Dizziness, lightheadedness, or fainting.
  • Change in heartbeat, such as a fast or irregular beat.
  • Shortness of breath.
  • Unusual tiredness.

Other side effects of disopyramide may include:


Call your doctor right away if you have:


Call your doctor right away if you have symptoms of heart failure, such as:

  • Shortness of breath when you rest or do activities that did not cause problems before.
  • Swelling of feet or legs.
  • Sudden weight gain, such as 3 lb or more in 2 to 3 days.


Call your doctor right away if you have:

  • Chest pain.
  • Shortness of breath.
  • Irregular heartbeat.
  • Swelling in feet or legs.
  • Trembling or shaking.


Call your doctor right away if you have:


Call your doctor right away if you have:

  • Chest pain.
  • Shortness of breath.
  • Changes in your heartbeat such as fast, slow, or irregular.
  • Dizziness, lightheadedness, or fainting.
  • Swelling in feet or legs.

Other side effects of propafenone may include a change in taste, such as metallic taste in your mouth.


Call your doctor right away if you have:

  • Stomach pain.
  • Yellow eyes or skin.
  • Vision changes.
  • Dizziness, lightheadedness, or fainting.
  • Confusion.


Call your doctor right away if you have:

  • Dizziness, lightheadedness, or fainting.
  • Fast heartbeats.

Other side effects of sotalol may include a slow heart rate.

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

What To Think About

Antiarrhythmic medicines might interact with many other medicines that you might take. Tell your doctor all of the medicines that you take. Be sure to include nonprescription medicines, vitamins, and natural supplements.

Grapefruit juice can affect some antiarrhythmic medicines such as sotalol. Ask your doctor if your medicine is affected by grapefruit juice and if you need to make any changes to avoid problems. For more information, see Grapefruit Juice and Medicines.


If you take amiodarone, your doctor will check you carefully for side effects to make sure you can take the medicine safely. Talk to your doctor if you have any side effects or any concerns about taking amiodarone. Because amiodarone can cause serious side effects, it is typically used for people who have severe symptoms when other medicines have failed.

Taking medicine

Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.

There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.

Advice for women

If you are pregnant, breast-feeding, or planning to get pregnant, do not use any medicines unless your doctor tells you to. Some medicines can harm your baby. This includes prescription and over-the-counter medicines, vitamins, herbs, and supplements. And make sure that all your doctors know that you are pregnant, breast-feeding, or planning to get pregnant.


Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

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.

ByHealthwise Staff
Primary Medical ReviewerRakesh K. Pai, MD, FACC - Cardiology, Electrophysiology
Specialist Medical ReviewerJohn M. Miller, MD, FACC - Cardiology, Electrophysiology

Current as ofMarch 12, 2014

WebMD Medical Reference from Healthwise

Last Updated: March 12, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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