Information for Healthcare Professionals: Amiodarone (marketed as Cordarone)
|Update: The issues described in this communication have been addressed in product labeling (see Drugs@FDA).|
Because of its potentially life-threatening side effects and the difficulties associated with managing its use, amiodarone should be prescribed for the treatment of only the following documented, life-threatening, recurrent ventricular arrhythmias when these arrhythmias have not responded to other antiarrhythmic agents or when alternative agents have not been tolerated:
Recurrent ventricular fibrillation
Recurrent hemodynamically unstable ventricular tachycardia
Patients must be hospitalized while the loading doses of amiodarone are administered. Amiodarone should be prescribed only by physicians experienced in the treatment of life-threatening arrhythmias who are thoroughly familiar with amiodarone’s risks and benefits and have access to laboratory facilities capable of adequately monitoring the effectiveness and side effects of amiodarone treatment.
Amiodarone has several potentially fatal toxicities. The most important of these is pulmonary toxicity (hypersensitivity pneumonitis or interstitial/alveolar pneumonitis). This has occurred as clinically manifest disease at rates as high as 17 percent in some series of patients with ventricular arrhythmias given doses of around 400 mg daily, as abnormal diffusion capacity without symptoms in a much higher percentage of patients. Pulmonary toxicity is fatal about 10 percent of the time.
Hepatic injury is common with amiodarone, but is usually mild and evidenced only by abnormal liver enzymes. Overt liver disease can occur, however, and has been fatal in a few cases.
Amiodarone can exacerbate the ventricular arrhythmia being treated by, for example, making the arrhythmia less well-tolerated or more difficult to reverse. This has occurred in approximately 2 to 5 percent of patients in various series, and significant heart block or sinus bradycardia has been seen in 2 to 5 percent of patients. Although the frequency of such proarrhythmic events does not appear greater with amiodarone than with other antiarrhythmic agents, the effects are prolonged when they occur, because amiodarone is very slowly metabolized and excreted (over months).
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