Examining the safety of amiodarone

Amiodarone is the most widely used antiarrhythmic agent, with demonstrated effectiveness against all the spectrum of cardiac tachyarrhythmias. The risk of adverse effects acts as a limiting factor to its utilization especially in the long term. This article systematically reviews the published evidence on amiodarone versus placebo to examine its safety as an antiarrhythmic drug.

Authors collected data on adverse effects reported in 49 randomized placebo-controlled trials with amiodarone. Adverse effects were classified according to the organ/system involved. Pooled estimates of the number needed to treat (NNT) and to harm (NNH) versus placebo were calculated.

Amiodarone is effective for both the acute conversion of atrial fibrillation (AF) (11 trials, NNT = 4 at 24 h; p = 0.003) and the prevention of postoperative AF (18 trials, NNT = 8; p < 0.001), although with an increased risk of bradycardia, hypotension, nausea or phlebitis (pooled NNH = 4; p < 0.001). Amiodarone administration for the maintenance of sinus rhythm has a favorable net clinical benefit (pooled NNT = 3; p < 0.001 versus pooled NNH for either thyroid toxicity, gastrointestinal discomfort, skin toxicity or eye toxicity = 11; p < 0.001). Treatment with amiodarone for the prophylaxis of sudden cardiac death has less favorable net clinical benefit (15 trials, NNT = 38; p < 0.001 versus NNH for either thyroid toxicity, hepatic toxicity, pulmonary toxicity or bradycardia = 14; p < 0.001). Amiodarone treatment in this setting should be used in only selected cases.