Class IA

MOA: These drugs block the fast sodium channels in the myocardium. They show intermediate dissociation from the sodium channels and lengthen the refractory period to stop the arrhythmia. The sodium channel is responsible for depolarization in the myocardium

Class IA Drugs

Quinidine

Procainamide (Prontestyl®)

Disopyramide (Norpace®)

Quinidine

No brand name

Used to treat supraventricular and ventricular arrhythmias

80% bound to protein

SE: Thrombocytopenia

One of the first antiarrhythmics and is still used today

Class IA

Procainamide

Pronestyl®

Used mainly for ventricular arrhythmias

Metabolized by N-acetyl transferase to N-acetylprocainamide, 50% is excrete unchanged in the urine

SE: Systemic Lupus erythamatous (SLE) like syndrome

Class IA

Disopyramide

Norpace®

Used primarily to prevent ventricular tachycardia and premature ventricular contractions

Half life=6.7 hours

SE: Has anticholinergic side effects

Class IA

Class IB

MOA: Blocks the fast sodium channels. Dissociate rapidly from the sodium channel and have the lowest potency

Class IB Drugs

Lidocaine (Xylocaine®)

Mexiletine (Mexitil®)

Tocainide (Tonocard®)

Lidocaine

Xylocaine®

Used primarily for premature ventricular contractions and ventricular arrhythmias, originally used as a local anesthetic

Class IB

Mexiletine

Mexitil®

Used as long term prophylaxis against ventricular tachycardia

Available as an oral formulation

Class IB

Tocainide

Tonocard®

Used chronically, available as an oral formulation

Class IB

Class IC

MOA: Block fast acting sodium channels, dissociate slowly from the sodium channels, therefore are the most potent

Class IC Drugs

Flecainide (Tambocor®)

Propafenone (Rythmol®)

Flecainide

Tambocor®

Good for suppressing ventricular automaticity by slowing AV conduction

Has local anesthetic activity

Class IC

Propafenone

Rythmol®

Used for supraventricular arrhythmias

Orally active, has weak beta blocking activity

Class IC

Class II

Beta Blockers

MOA: Stabilizes or depresses the membrane through inhibition of adrenergic stimulation to the heart, slows the heart rate and ectopic tachycardias

Class II Drugs

Propranolol (Inderal®)

Esmolol (Brevibloc®)

Acebutolol (Sectral®)

Propranolol

Inderal®

Used for the treatment of supraventricular arrhythmias and ventricular tachycardias

Major metabolite: Napthoxylactic acid 

Class II

Esmolol

Brevibloc®

 Used for inoperative and other arrhythmias

Short acting, IV only

Class II

Acebutolol

Sectral®

Used for premature ventricular contractions and ventricular tachycardia

Active metabolite: diacetolol

Class II

Class III

Repolarization Prolongators

MOA: Prolong action potential thus increasing the refractory period of the membrane action potential. May also block potassium and sodium channels

Class III Drugs

Amiodarone (Cordarone®)

Dronedarone (Multaq®)

Sotalol (Betapace®)

Ibutilide (Covert®)

Dofetilide (Tikosyn®)

Amiodarone

Cordarone®

Used to control refractory ventricular tachycardias, prevent ventricular fibrillation, and atrial fibrillation (non-FDA)

SE: Pulmonary toxicity, thyroid toxicity, interstitial fibrosis, phototoxicity, optic neuritis

Class III

Dronedarone

Multaq®

Used for persistent atrial fibrillation and atrial flutter

SE: Less pulmonary side effects, thyroid effects, and neurological activity than Amiodarone

Class III

Sotalol

Betapace®

Used for ventricular arrhythmias and atrial fibrillation

Available orally

Class III

Ibutilide

Corvert®

Blocks potassium channel and /or slow sodium channels

Used to convert atrial fibrillation and atrial flutter to normal sinus rhythm

SE: Torsade de pointe

Class III

Dofetilide

Tikosyn®

Used for the conversion and management of atrial flutter to normal sinus rhythm

SE: Torsade de pointe

Class III

Class IV

Calcium Channel Blockers

 MOA: These block slow inward current of Ca²⁺ ions during phase 2 of action potential, Slow down AV conduction and the sinus rate

SE: Bradycardia, hypotension, headache, edema

Class IV

Class IV Drugs

Verapamil (Calan®, Isoptin®)

 Diltiazem (Cardizem®, Dilacor®) 

Verapamil

Calan®, Isoptin®

Used to control atrial and paroxysmal tachycardia

Class IV

Diltiazem

Cardizem®, Dilacor®

Used to control atrial and paroxysmal tachycardia

Class IV

Miscellaneous Antiarrhythmics

Adenosine (Adenocard®)

Magnesium Sulfate

Potassium

Adenosine

Adenocard®

MOA: Activates inward rectifier potassium; blocks calcium current

Nucleoside that occurs naturally in the body

Miscellaneous

Magnesium Sulfate

No Brand Name

MOA: Poorly understood; interacts with Na⁺, K⁺ ATPase, K⁺ and Ca²⁺ channels

Miscellaneous

Potassium

No Specific Brand Name

MOA: Increases K⁺ permeability, K⁺ currents

Miscellaneous