Table 3.4-2. Antiarrhythmic agents

Agent

Dosage

Contraindications

Acutea

Long term

Adenosine (IV)

6 mg in rapid IV injection followed by 12 or 18 mg after 1-2 min when necessary

Sinus node dysfunction, second-degree or third-degree AV block,b VT, asthma. Use with caution in AF or AFL with suspected accessory pathway, prolonged QT, severe HF, or hypotension

Amiodarone (IV, PO)

5 mg/kg (most often 300 mg) IV over 15-30 min (infusions over 60-120 min are safer) followed by 360 mg (1 mg/min) over 6 h and then by 540 mg (0.5 mg/min) over 18 h; max, 1200 mg/d (sometimes up to 2000 mg/d)

Loading dose: 200 mg (in selected cases 400 mg) tid for 7-14 days followed by 200 mg bid for 7-14 days

Maintenance dose: usually 200 mg/d, in selected cases 100 or 300-400 mg/d

Sinus node dysfunction, second-degree or third-degree AV block,b prolonged QT, drug hypersensitivity, thyrotoxicosis, liver disease, pregnancy, breastfeeding

Digoxin (IV, PO)

0.25 mg IV every 2 h; max total dose, 1.5 mg

0.125-0.375 mg/d

Bradycardia,b second-degree or third-degree AV block,b sick sinus syndrome,b carotid sinus syndrome, hypertrophic cardiomyopathy with outflow tract obstruction, preexcitation syndromes, hypokalemia, hypercalcemia, planned electrical cardioversion

Diltiazem (PO)

90-240 mg/d

HF, second-degree or third-degree AV blockb

Dronedarone (PO)

400 mg bid

Second-degree or third-degree AV block,b sick sinus syndrome,b HF or asymptomatic LV dysfunction, permanent AF

Flecainide (IV, PO)

2 mg/kg IV bolus (max, 150 mg)

50-150 mg PO bid

Structural heart disease (in particular heart failure), CAD, sinus node dysfunction, second-degree or third-degree AV blockb

Lidocaine (IV)

50 mg IV over 2 min; can be repeated every 5 min up to total of 200 mg followed by infusion of 1-4 mg/min; dose should be tapered off

Hypersensitivity to local anesthetic drugs

Metoprolol (IV, PO)

5 mg IV every 5-10 min up to total of 15 mg

50-200 mg/d

Second-degree or third-degree AV block,b symptomatic bradycardia, symptomatic hypotension, sick sinus syndrome, decompensated HF, asthma

Procainamide (IV)

Loading dose: 100-200 mg/dose or 15-18 mg/kg; do not exceed 50 mg/min; can be repeated every 5 min if required; do not exceed 1 g

Maintenance dose: 1-4 mg/min IV infusion

Sinus node dysfunction, second-degree or third-degree AV blockb, prolonged QT, drug hypersensitivity

Propranolol (IV, PO)

1-5 mg IV (in selected cases 10 mg); administer 1 mg over 1 min

20-40 mg every 8 h

Second-degree or third-degree AV block,b symptomatic bradycardia, symptomatic hypotension, sick sinus syndrome, decompensated HF, asthma

Propafenone (IV, PO)

1-2 mg/kg IV over 5 min

150-300 mg every 8-12 h

Structural heart disease (in particular HF), CAD, sinus node dysfunction, second-degree or third-degree AV blockb

Sotalol (PO)

80-160 mg every 12 h

80-160 mg every 12 h

Sinus node dysfunction, second-degree or third-degree AV block,b prolonged QT, asthma, renal failure (creatinine clearance <40 mL/min)

Verapamil (IV, PO)

5-10 mg IV over 1-2 min

120-360 mg/d

HF, second-degree or third-degree AV blockb

a Monitor electrocardiography and blood pressure.

b In patients without an implanted pacemaker.

AF, atrial fibrillation; AFL, atrial flutter; AV, atrioventricular; bid, 2 times a day; CAD, coronary artery disease; HF, heart failure; IV, intravenous; LV, left ventricle; PO, oral; tid, 3 times a day; VT, ventricular tachycardia.