Antiarrhythmic agents

Information about Antiarrhythmic agents

The antiarrhythmics are a heterogeneous group of medications that act to decrease cardiac automaticity and slow conduction, and are used for either or both ventricular and atrial arrhythmias. The most common use of antiarrhythmics is in the treatment of atrial fibrillation or flutter, or prevention of their recurrence in patients after electrical or medical cardioversion. Use of antiarrhythmics for suppression of ventricular arrhythmias is controversial in that several studies have shown that suppression of ventricular premature contractions can be associated with a decrease rather than increase in survival. Thus, the antiarrhythmics are generally used only for clinically significant ventricular dysrrhythmias.

The oral antiarrhythmics are often separated into classes based upon their major molecular target as either class I (sodium channel), II (beta adrenergic receptor), III (potassium channel), or IV (calcium channel). Many agents have multiple targets, but the classification is helpful particularly because of shared side effects.

Oral antiarrhythmics available in the United States (and their year of approval) include quinidine (1950), procainamide (1950), disopyramide (1977), amiodarone (1985), flecainide (1985), mexiletine (1985), propafenone (1989) and dronedarone (2009). Agents used intravenously, usually for a short period only with severe arrhythmias, include adenosine (1989), ibutilide (1995), isoproterenol (1992) and dofetilide (2000). Agents used to slow atrial-ventricular conduction include cardiac glycosides (digoxin, digitoxin), calcium channel blockers (diltiazem, verapamil), and beta adrenergic blockers (esmolol, propranolol, and sotalol) which are discussed elsewhere.

Amiodarone is a well established cause of drug induced liver injury and can cause both an acute as well as a chronic liver injury with cirrhosis. Dronedarone, a non-iodinated derivative of amiodarone, has been implicated in several cases of severe acute liver failure and may share the propensity for hepatotoxicity of amiodarone. The other antiarrhythmics are rare causes of liver injury, their cardiac and central nervous system adverse events usually overshadowing the idiosyncratic effects on the liver.

List of antiarrhythmic agents:

• Amiodarone
• Disopyramide
• Dofetilide
• Dronedarone
• Flecainide
• Ivabradine
• Mexiletine
• Procainamide
• Propafenone
• Quinidine

• Dailymed label info on Antiarrhythmic agents
• FDA Antiarrhythmic agents

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