What do I need to know about antiarrhythmics?

Antiarrhythmics improve the rhythm of your heart. Rhythm is the pattern of your heartbeat. In addition to the medicines listed below, there are other medicines that can also be used to treat arrhythmias. These include calcium channel blockers and beta-blockers.

When are antiarrhythmics prescribed?

Your doctor may prescribe this type of medicine when your heart beats too slowly. This slow beat is a condition known as bradycardia. Your doctor may also prescribe this medicine if your heart beats too fast. This fast beat is a condition known as tachycardia. In addition, your doctor may prescribe an antiarrhythmic if your heart beats in an irregular pattern. When you have an irregular heartbeat, your heart may beat too fast, too slow, or even miss beats. Or, it may do all of these at different times.

Common Names of Antiarrhythmics

The following table lists some common brand and generic names for antiarrhythmics.

brand generic
Betapace sotalol
Calan verapamil HCl
Calan SR verapamil HCl
Cardioquin quinidine polygalacturonate
Cordarone amiodarone HCl
Dilantin Infatab phenytoin
Dilantin Kapseals phenytoin
Dilantin-125 phenytoin
Ethmozine moricizine HCl
Isoptin verapamil HCl
Isoptin SR verapamil HCl
Mexitil mexiletine HCl
Norpace disopyramide
Norpace CR disopyramide
Pacerone amiodarone HCl
Procanbid procainamide HCl
Pronestyl procainamide HCl
Pronestyl-SR procainamide HCl
Quinaglute Dura-Tabs quinidine gluconate
Quinalan quinidine gluconate
Quinidex quinidine sulfate
Quinora quinidine sulfate
Rythmol propafenone HCl
Tambocor flecainide acetate
Tonocard tocainide HCl
Verelan PM verapmil HCl

How Antiarrhythmics Work

The rhythm of your heart is guided by a part of your heart muscle called the sinoatrial node, or SA node for short. An electrical impulse begins at the SA node. Then the impulse leaves the node and travels on a pathway through the heart muscle. Finally, it reaches another section of your heart called the atrioventricular node, or AV node for short. Sodium and potassium moving through channels within the heart muscle regulate how this impulse travels. If atherosclerosis decreases the blood flow to any of these areas of the heart, then the way this impulse travels can change. This affects the rhythm of your heart.

Antiarrhythmics work by correcting the patterns of electrical conduction in your heart. Some antiarrhythmics work directly at the SA or AV node to regulate the heart rhythm. Other types can change the amount of sodium or potassium traveling through the channels in the heart muscle. This can restore a normal heart rhythm.

Precautions and Possible Side Effects of Antiarrhythmics

Precautions to take when you are on antiarrhythmics:

  • Keep all your appointments with your doctor. Your doctor will need to supervise you closely when you are on this type of medicine. These medicines can sometimes worsen the rhythm of your heartbeat until your doctor finds the best dose for you.

Possible side effects of antiarrhythmics that you may notice:

  • blurred vision
  • dizziness
  • dry mouth
  • fatigue
  • headache
  • irregular heart rhythm or palpitations
  • lung or breathing difficulties
  • nausea with or without vomiting
  • sleep disorders

If you experience any of these side effects, report them to your doctor right away.

Possible side effects of antiarrhythmics that you may not notice: Although you may not be aware that your body is experiencing any of the following changes, your doctor will be able to test for these side effects during an office visit. Be sure to keep all follow-up appointments with your doctor.

  • abnormal liver function
  • changes in the number of white blood cells
  • low blood pressure

Possible Drug Interactions With Antiarrhythmics

Many of the antiarrhythmics can have harmful effects when you take them with other medicines. Always tell your doctor about all the medicines that you take. Do not use any other medicine without your doctor's okay. This includes:

  • prescription medicines ordered by another doctor
  • over-the-counter medicines
  • herbal remedies
  • vitamins and minerals

It's best to keep an updated list of these and bring a copy to give your doctor. Thay way you can add to it whenever you take something new or delete the types you no longer take. Make a copy for each of your doctors so that they can keep it in your file. This complete list helps your doctor be better prepared to prescribe an antiarrhythmic that's the least likely to interact with your other treatments.

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