Agent	Loading dose	Onset of action	Maintenance dosage	Major side effects
Digoxin (Lanoxin)	0.25 mg IV or orally every 2 hours, up to 1.5 mg	5 to 30 minutes for IV therapy or 30 minutes to 2 hours for oral therapy	0.125 to 0.25 mg every day (oral or IV)	Digitalis toxicity, heart block, bradycardia
Diltiazem (Cardizem)	0.25 mg per kg IV over 2 minutes	2 to 7 minutes	10 to 15 mg per hour IV or 120 to 360 mg orally every day in divided doses	Hypotension, heart block, heart failure
Verapamil (Calan, Isoptin)	0.075 to 0.15 mg per kg IV over 2 minutes	3 to 5 minutes	240 to 360 mg orally every day in divided doses	Hypotension, heart block, heart failure
Esmolol (Brevibloc)	0.5 mg per kg IV over one minute	5 minutes	0.05 to 0.2 mg per kg per minute IV	Hypotension, heart block, bradycardia, asthma, heart failure
Metoprolol (Lopressor)*	2.5 to 5 mg IV bolus over 2 minutes, up to 3 doses	5 minutes	50 to 200 mg orally every day in divided doses	Hypotension, heart block, bradycardia, asthma, heart failure
Propranolol (Inderal)	0.15 mg per kg	5 minutes	40 to 320 mg orally every day in divided doses	Hypotension, heart block, bradycardia, asthma, heart failure