Amiodarone (Cordarone, Pacerone) is an anti-dysrhythmic agent used for the treatment and prophylaxis of ventricular fibrillation and ventricular tachycardia1. Although the exact mechanism of action is unknown (come on, scientists), Amiodarone increases the refractory period and slows conduction of the cardiac action potential by altering potassium channels1, 2. Although, not indicated for this purpose, it is the most effective medication for atrial fibrillation- frequently used intravenously to convert to a normal sinus rhythm and orally to maintain NSR1, 2.
Despite it’s effectiveness, Amiodarone is often reserved for those who have not responded to safer drugs. Amiodarone is highly lipid soluble and accumulates in many tissues, primarily the liver and lungs2. It’s half life is approximately 58 days, so it continue to act, or cause adverse effects, for weeks after dosing has stopped1, 2. Lung damage- pneumonitis, pulmonary fibrosis, alveolar hemmorhage, pleural effusion- is the greatest concern and patient’s receiving long-term, high-dose therapy are at higher risk(2, 3). Amiodarone is also cardiotoxic and may increase dysrhythmic activity causing sinus bradycardia or AV block2. Liver toxicity is also a concern, so hepatic function tests and signs of liver injury- nausea, vomiting, jaundice, dark urine- should be monitored2. Intravenous Amiodarone may cause hypotension, bradycardia or AV block, and phlebitis2.
Amiodarone is metabolized by the enzyme CYP3A4 in the liver2. Remember that grapefruit juice (who drinks this anyway?) inhibits this enzyme and will increase Amiodarone levels!
2. Lehne, R. A. (2013). Pharmacology for Nursing Care, 8th Edition Retrieved from https://pageburstls.elsevier.com/#/books/978-1-4377-3582-6/