Amiodarone in the prevention and treatment of arrhythmia.

There is good evidence that amiodarone is effective against a variety of arrhythmias and that it may be superior to other drugs in some settings. Because of its proven efficacy and safety, amiodarone is currently the leading antiarrhythmic drug. The electrophysiological actions of amiodarone are complex and not completely understood. It is generally classified as a Vaughan-Williams class III agent, prolonging repolarization by inhibition of outward potassium channels. Amiodarone is particularly useful because its safety has been clearly demonstrated by a large body of evidence, including several randomized trials. Compared with many other antiarrhythmic drugs, amiodarone causes few cardiovascular adverse effects; however, its overall tolerance is limited by considerable non-cardiac toxicity. Although amiodarone will continue to give way to the implantable cardioverter defibrillator (ICD) as primary therapy for many patients presenting with sustained ventricular tachycardia (VT) or ventricular fibrillation (VF), it is likely that the use of amiodarone in ICD patients will continue to prevent ICD discharges. Evaluation of combined use of amiodarone and ICD may provide the first opportunity to conduct a placebo-controlled trial of amiodarone efficacy against VT recurrence. Pharmacological therapy remains the major approach to management of atrial fibrillation (AF), and the use of amiodarone is likely to increase in future years. This review will analyze the evidence that amiodarone is a safe and effective antiarrhythmic drug.