Question: Could you tell me if the drug procainamide is similar and/or the same as amiodarone and why the former is not marketed in some countries and in others it is? Cecilia (Argentina).
Answer: Procainamide is a different class antiarrhythmic and therefore a different mechanism of action than amiodarone. It can be used both intravenously in acute arrhythmias, and orally in chronic or recurrent arrhythmias. Amiodarone has more indications according to the arrhythmia management guidelines, because there is more scientific evidence on its use, and partly because procainamide can produce important adverse effects such as lupus and bone marrow disorders. We do not know the reason why it is not marketed in Argentina. In Spain very little is used, much less than amiodarone.