- Recurrent ventricular fibrillation.
- Recurrent hemodynamically unstable ventricular tachycardia.
As is the case for other antiarrhythmic agents, there is no evidence from controlled trials that the use of Amiodarone Tablets favorably affects survival.
Amiodarone should be used only by physicians familiar with and with access to (directly or through referral) the use of all available modalities for treating recurrent life threatening ventricular arrhythmias, and who have access to appropriate monitoring facilities, including in-hospital and ambulatory continuous electrocardiographic monitoring and electrophysiologictechniques. Because of the life-threatening nature of the arrhythmias treated, potential interactions with prior therapy, and potential exacerbation of the arrhythmia, initiation of therapy with Amiodarone should be carried out in the hospital.
- A prolongation of the myocardial cell-action potential duration and refractory period
- Non-competitive antagonism of α- and β-adrenoceptors.
Amiodarone prolongs the duration of the action potential of all cardiac fibers while causing minimal reduction of dV/dt (maximal upstroke velocity of the action potential). The refractory period is prolonged in all cardiac tissues. Amiodarone increases the cardiac refractory period without influencing resting membrane potential, except in automatic cells where the slope of the prepotential is reduced, generally reducing automaticity. These electrophysiologic effects are reflected in a decreased sinus rate of 15 to 20%, increased PR and QT intervals of about 10%, the development of U-waves, and changes in T-wave contour. These changes should not require discontinuation of Amiodarone as they are evidence of its pharmacological action, although Amiodarone can cause marked sinus bradycardia or sinus arrest and heart block. On rare occasions, QT prolongation has been associated with worsening of arrhythmia
Dosage & Administration
Pregnancy & Lactation
Use in Special Population
Geriatric Use: Clinical studies of Amiodarone HCl tablets did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.