<prompt> A 69-year-old man with heart failure and paroxysmal atrial fibrillation is prescribed amiodarone for maintenance of sinus rhythm. Which of the following is a known characteristic of amiodarone?excellent oral absorptiona short half-lifean active metabolitefew drug interactions  <response>: With prolonged treatment, the active N-desethyl derivative of amiodarone accumulates in plasma, and its concentration may exceed that of the parent compound. Amiodarone is poorly approximately 30 absorbed and there is marked interindividual variability. The half-life is long, 25-60 days, presumably because it is extensively bound to tissues, resulting in a large volume of distribution and a reservoir of drug. Complicating the use of amiodarone is multiple drug interactions and toxicities including liver, thyroid, and lung. 