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