Amiodarone Therapy: Updated Practical Insights

Abstract

Amiodarone, a bi-iodinated benzofuran derivative, is among the most commonly used antiarrhythmic drugs due to its high level of effectiveness. Though initially categorized as a class III agent, amiodarone exhibits antiarrhythmic properties across all four classes of antiarrhythmic drugs. Amiodarone is highly effective in maintaining sinus rhythm in patients with paroxysmal atrial fibrillation while also playing a crucial role in preventing a range of ventricular arrhythmias. Amiodarone has a complex pharmacokinetic profile, characterized by a large volume of distribution and a long half-life, which can range from several weeks to months, resulting in prolonged effects even after discontinuation. Side effects may include thyroid dysfunction, pulmonary fibrosis, and hepatic injury, necessitating regular follow-ups. Additionally, amiodarone interacts with several drugs, including anticoagulants, which must be managed to prevent adverse effects. Therefore, a deep understanding of both oral and intravenous formulations, as well as proper dosage adjustments, is essential. The aim of this paper is to provide a comprehensive and updated review on amiodarone's indications, contraindications, recommended dosages, drug interactions, side effects, and monitoring protocols.

Keywords: QT prolongation; amiodarone; amiodarone-induced hypothyroidism; amiodarone-induced keratopathy; amiodarone-induced pulmonary toxicity; amiodarone-induced thyrotoxicosis; atrial fibrillation; blue-grey syndrome; ventricular fibrillation; ventricular tachycardia.

Figure 2

Amiodarone treatment monitoring. Adapted from The North American Society of Pacing and Electrophysiology [183] and NHS Derbyshire Joint Area Prescribing Committee recommendations [184]. * Yellow-coded risk factors according to the 2021 EHRA guidelines; HR, heart rate; ECG, electrocardiogram; DLCO, diffusing capacity of the lungs for carbon monoxide; EHRA, European Heart Rhythm Association. (Created with BioRender.com; accessed on 9 September 2024).

Figure 1

Amiodarone side effects. AV, atrioventricular; AIH, amiodarone-induced hypothyroidism; AIT, amiodarone-induced thyrotoxicosis; G.I., gastrointestinal; G.U., genitourinary. (Created with BioRender.com; accessed on 9 September 2024 ).