Pharmacotherapeutic Group: Amiodarone Hydrochloride is a member of antiarrhythmic drugs with predominantly class III (Vaughan William's classification) effects.
Pharmacology: Pharmacodynamics: Mechanism of Action: The antiarrhythmic effect of Amiodarone HCl may be due to at least 2 major properties: a prolongation of the myocardial cell-action potential duration and refractory period; and noncompetitive alpha- and beta-adrenergic inhibition.
Pharmacokinetics: Absorption: Following oral administration in man, Amiodarone HCl is slowly and variably absorbed. The bioavailability of Amiodarone HCl is approximately 50%, but varies between 35 and 65% in various studies. Maximum plasma concentrations are attained 3 to 7 hours after a single dose.
Distribution: Amiodarone HCl has a very large but variable volume of distribution, averaging about 60 L/kg because of extensive accumulation in various sites, especially adipose tissue and highly perfused organs such as the liver, lung, and spleen.
Metabolism: One major metabolite of Amiodarone HCl, desethylamiodarone, has been identified in man.
Elimination: The main route of elimination is via hepatic excretion into bile, and some enterohepatic recirculation may occur.