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The information provided here is meant to give you a general idea about each of the medications listed below. Only the most general side effects are included, so ask your doctor if you need to take any special precautions. Use each of these medications as recommended by your doctor, or according to the instructions provided. If you have further questions about usage or side effects, contact your doctor.

Treatment of arrhythmias depends on the type and seriousness of the particular rhythm disturbance. Medications are most often used to treat tachyarrhythmias (fast heart rates).

Prescription Medications

Class IA

  • Quinidine (Quinora, Quinidex, Quinaglute, Cardioquin)
  • Procainamide (Pronestyl)
  • Disopyramide (Norpace)

Class IB

  • Phenytoin (Dilantin)
  • Tocainide (Tonocard)
  • Mexiletine (Mexitil)

Class IC

  • Flecainide (Tambocor)
  • Propafenone (Rythmol)
  • Moricizine (Ethmozine)

Class II: Beta-blockers

  • Propranolol (Inderal)
  • Metoprolol (Lopressor)

Class III

  • Bretylium
  • Amiodarone (Cordarone, Pacerone)
  • Sotalol (Betapace)
  • Ibutilide (Corvert)
  • Dofetilide (Tikosyn)

Class IV: Calcium Channel Blockers

  • Diltiazem (Cardizem, Dilacor, Tiazac)
  • Verapamil (Calan, Isoptin, Verelan)

Miscellaneous

  • Digitalis glycosides (Digoxin, Lanoxin)
  • Adenosine (Adenocard)

Prescription Medications

In one way or another, all of these drugs act to slow the electrical activity in the heart. Many of them have additional uses, such as treating high blood pressure. All of them can produce serious side effects and must be used with great care and strict adherence to instructions.

Class I
Class IA

Common names include:

  • Quinidine (Quinora, Quinidex, Quinaglute, Cardioquin)
  • Procainamide (Pronestyl)
  • Disopyramide (Norpace)
Class IB

Common names include:

  • Phenytoin (Dilantin)
  • Tocainide (Tonocard)
  • Mexiletine (Mexitil)

Class IC

Common names include:

  • Flecainide (Tambocor)
  • Propafenone (Rythmol)
  • Moricizine (Ethmozine)

Class I drugs are the most prone to side effects outside the circulatory system.

Possible side effects include:

  • Seizures
  • Confusion
  • Coma
  • Nausea
  • Dry mouth
  • Vomiting
  • Diarrhea
  • Constipation
  • Mental changes
  • Bone marrow damage
  • Clumsiness
  • Vision and hearing changes
  • Rashes
  • Unwanted heart rhythm changes

Class II: Beta-blockers

Common names include:

  • Propranolol (Inderal)
  • Metoprolol (Lopressor)

There are many beta-blockers, but generally these two are the ones used to treat arrhythmias. All beta-blockers are used primarily for blood pressure control or to treat angina . Side effects are less wide ranging than Class I drugs.

Possible side effects include:

  • Breathing problems (wheezing)
  • Heart failure
  • Fatigue

Class III

Common names include:

  • Bretylium
  • Amiodarone (Cordarone, Pacerone)
  • Sotalol (Betapace)
  • Ibutilide (Corvert)
  • Dofetilide (Tikosyn)

These agents are generally reserved for life-threatening ventricular arrhythmias and those that have been resistant to other treatments.

Possible side effects include:

  • Dizziness
  • Nausea
  • Unwanted heart rhythm changes
  • Liver problems (sotalol, amiodarone)
  • Lung damage (sotalol, amiodarone)
  • Eye damage (amiodarone)
  • Nerve damage (sotalol)
  • Muscle damage (sotalol)
  • Thyroid changes (sotalol, amiodarone)

Class IV: Calcium Channel Blockers
  • Diltiazem (Cardizem, Dilacor, Tiazac)
  • Verapamil (Calan, Isoptin, Verelan)

Most of the drugs in this category are used to lower blood pressure or treat angina.

Common side effects include:

  • Dizziness
  • Nausea
  • Water retention

There is also a long list of more serious but rare side effects, depending upon the particular drug, which include:

  • Liver damage
  • Kidney damage
  • Bone marrow damage
  • Worsening heart failure
  • Undesirable heart rhythm changes

Miscellaneous
Digitalis Glycosides ( Digoxin , Lanoxin)

These drugs are very effective at treating heart failure, but have much more restricted use in heart rhythm disturbances. They are primarily used to control the rate of ventricular response to tachyarrhythmias. Digitalis glycosides have a very narrow therapeutic window between taking too little and taking too much.

Common side effects include:

  • Nausea
  • Vomiting
  • Unwanted heart rhythm changes

Adenosine (Adenocard)

Adenosine is given intravenously to stop certain tachyarrhythmias (rapid heartbeat).

Common side effects include:

  • Chest pressure
  • Shortness of breath
  • Nausea
  • Flushing
  • Headache
  • Dizziness

Special Considerations

Whenever you are taking a prescription medication, take the following precautions:

  • Take your medicine as directed. Do not change the amount or the schedule.
  • Do not stop taking them without talking to your doctor.
  • Do not share them.
  • Know what the results and side effects may be. Report them to your doctor.
  • Some drugs can be dangerous when mixed. Talk to a doctor or pharmacist if you are taking more than one drug. This includes over-the-counter medicine and herb or dietary supplements.
  • Plan ahead for refills so you don’t run out.

References:

Drug Facts and Comparisons . 56th ed. Facts and Comparisons; 2001.

Ferri F, ed. Ferri’s Clinical Advisor 2010. 1st ed. Philadelphia: Mosby Elsevier, 2009.

Goldman L, Ausiello D, eds. Cecil Textbook of Internal Medicine . 23rd ed. Philadelphia: Saunders, 2008.

Goldschlager N, Epstein AE, Naccarelli G, et al. Practical guidelines for clinicians who treat patients with amiodarone. Practice Guidelines Subcommittee, North American Society of Pacing and Electrophysiology. Arch Intern Med. 2000;160:1741.

Harrison's Principles of Internal Medicine. 14th ed. McGraw-Hill; 1998.

Libby P, et al. Braunwald’s Heart Disease .8th ed. Philadelphia: Saunders, 2007.

Mayo Clinic and Foundation for Medical Education and Research website. Available at: http://www.mayo.edu/ .

National Heart, Lung, and Blood Institute website. Available at: http://www.nhlbi.nih.gov/ .

Noble J. Textbook of Primary Care Medicine . 3rd ed.

Rakel R. Textbook of Family Medicine 2007 . 7th ed. Philadelphia: Saunders Elsevier, 2009.

Rakel RE, Bope ET. Conn's Current Therapy . 60th ed. Philadelphia: Saunders Elsevier, 2009.

Triola BR, Kowey PR. Antiarrhythmic drug therapy. Curr Treat Options Cardiovasc Med. 2006;8(5):362-370.

Viskin S, Fish R, Glick A, et al. The adenosine triphosphate test: a bedside diagnostic tool for identifying the mechanism of supraventricular tachycardia in patients with palpitations. J Am Coll Cardiol. 2001;38:173.



Last reviewed December 2013 by Michael J. Fucci, DO

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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