Antiarrhythmic drugs CLASSES OF ANTIARRHYTHMIC DRUGS Class I Antiarrhythmics – Na+channel blockers Subclass IA – Moderate Na+channel blockers Quinidine Procainamide (side effects: drug-induced lupus herythematosus) Disopyramide (anticholinergic side effects) Subclass IB – Mild Na+channel blockers Lidocaine Mexiletine (oral lidocaine derivative with similar activity) Tocainide (not frequently used because of potential bone marrow suppression) Phenytoin (adinistered as a salt to avoid sedative effects) Subclass IA – Marked Na+channel blockers Encainide Flecainide (active in all parts of the heart) Propafenone Class II Antiarrhythmics – β-blockers Propanolol Acebutolol Esmolol Metoprolol Sotalol Class III antiarrhythmics – K+channel blockers Amiodarone Dronedarone Class IV antiarrhythmics – Ca2+ channel blockers Diltiazem Verapamil Bepridil
