Adenosine | Slows AV nodal conduction | Narrow complex tachycardias, stable supraventricular tachycardia, and wide-complex tachycardias if supraventricular in origin | 6 mg over 1–3 s; 12 mg repeat dose | Initial dose 0.1–0.2 mg/kg; subsequent doses doubled to maximum single dose of 12 mg | Recommended as diagnostic or therapeutic maneuver for supraventricular tachycardias; give as rapid IV bolus. Vasodilates, BP may decrease. Theoretical risk of angina, bronchospasm, proarrhythmic action. Drug–drug interaction with theophylline, dipyridamole. |
Atropine | Anticholinergic (parasympatholytic). Increases sinoatrial node rate and automaticity; increases AV node conduction | Symptomatic brachycardia, AV block | 0.5–1.0 mg repeated every 3–5 min | 0.02 mg/kg | Repeat atropine doses every 5 min to a total dose of 3 mg in adults or 0.5 mg in children, 1.0 mg in adolescents. The minimum pediatric dose is 0.1 mg. Do not use for infranodal (Mobitz II) block. |
Epinephrine | α-Adrenergic effects increase myocardial and cerebral blood flow. β-Adrenergic effects may increase myocardial work and decrease subendocardial perfusion and cerebral blood flow | VF/VT, electromechanical dissociation, ventricular asystole, severe bradycardia unresponsive to atropine or pacing Severe hypotension | 1 mg IV 0.03 mcg/kg/min in an infusion increased to effect | Initial dose 0.01 mg/kg IV; repeat same for subsequent doses 1 mcg/kg | Repeat doses every 3–5 min as necessary. An infusion of epinephrine (eg., 1 mg in 250 mL D5W or NS, 4 mcg/mL) can be titrated to effect in adults (1–4 mcg/min) or children (0.1–1 mcg/kg/min). Administration down a tracheal tube requires higher doses (2–2.5 mg in adults, 0.1 mg/kg in children). High-dose epinephrine (0.1 mg/kg) in adults is recommended only after standard therapy has failed. |
Lidocaine | Decreases rate of phase 4 depolarization (decreases automaticity); depresses conduction in reentry pathways. Elevates VF threshold. Reduces disparity in action potential duration between normal and ischemic tissue. Reduces action potential and effective refractory period duration | VT that has responded to defibrillation; premature ventricular contractions. Use only after ROSC; found to be less effective than amiodarone in VF or pulseless VT following OHCA | 1–1.5 mg/kg | 1 mg/kg | Doses of 0.5–1.5 mg/kg can be repeated every 5–10 min to a total dose of 3 mg/kg. After infarction or successful resuscitation, a continuous infusion (eg, 1 g in 500 mL D5W, 2 mg/mL) should be run at a rate of 20–50 mcg/kg/min (2–4 mg/min in most adults). Therapeutic blood levels are usually 1.5–6 mcg/mL. |
Vasopressin | Nonadrenergic peripheral vasoconstrictor; direct stimulation of V1 receptors | Bleeding esophageal varices; adult shock-refractory VF; hemodynamic support in vasodilatory (septic) shock | 40 units IV, single dose, 1 time only | Not recommended | Newly recommended as equivalent to epinephrine in VF and PEA; may be more effective in asystole; used only one time; has a 10–20 min half-life. |
Procainamide | Suppresses both atrial and ventricular arrhythmias | AF/flutter; preexcited atrial arrhythmias with rapid ventricular response; wide-complex tachycardia that cannot be distinguished as SVT or VT | 20 mg/min until arrhythmia suppressed, hypotension develops, QRS complex increases by >50%, or total dose of 17 mg/kg has infused. In urgent situation, 50 mg/min may be used to maximum of 17 mg/kg. Maintenance infusion, 1–4 mg/min | Loading dose: 15 mg/kg; infusion over 30–60 min; routine use in combination with drugs that prolong QT interval is not recommended | Contraindicated in overdose of tricyclic antidepressants or other antiarrhythmic drugs. Bolus doses can result in toxicity. Should not be used in preexisting QT prolongation or torsades de pointes. Blood levels should be monitored in patients with impaired renal function and when constant infusion >3 mg/min for >24 h. |
Amiodarone | Complex drug with effects on sodium, potassium, and calcium channels as well as α- and β-adrenergic blocking properties | SVT with accessory pathway conduction; unstable VT and VF; stable VT, polymorphic VT, wide-complex tachycardia of uncertain origin; AF/flutter with CHF; preexcited AF/flutter; adjunct to electrical cardioversion in refractory PSVTs, atrial tachycardia, and AF | 150 mg over 10 min, followed by 1 mg/min for 6 h, then 0.5 mg/min, with supplementary infusion of 150 mg as necessary up to 2 g. For pulseless VT or VF, initial administration is 300 mg rapid infusion diluted in 20–30 mL of saline or dextrose in water | 5 mg/kg for pulseless VT/VF; for perfusing tachycardia loading dose, 5 mg/kg IV/IO; maximum dose, 15 mg/kg/d | Antiarrhythmic of choice, particularly if cardiac function is impaired, EF <40%, or CHF. Routine use in combination with drugs prolonging QT interval is not recommended. Most frequent side effects are hypotension and bradycardia. |
Verapamil | Calcium channel blocking agent used to slow conduction and increase refractoriness in AV node, terminating reentrant arrhythmias that require AV nodal conduction for continuation | Controls ventricular response rate in AF/flutter and MAT; rate control in AF; terminating narrow-complex PSVT | 2.5–5 mg IV over 2 min; without response, repeat dose with 5–10 mg every 15–30 min to a max of 20 mg | | Use only in patients with narrow-complex PSVT or supraventricular arrhythmia. Do not use in presence of impaired ventricular function or CHF |
Diltiazem | Calcium channel blocking agent used to slow conduction and increase refractoriness in AV node, terminating reentrant arrhythmias that require AV nodal conduction for continuation | Slows conduction and increases refractoriness in AV node. May terminate reentrant arrhythmias. Controls ventricular response rate in AF/flutter and MAT | 0.25 mg/kg, followed by second dose of 0.35 mg/kg if necessary; maintenance infusion of 5–15 mg/h in AF/flutter | | May exacerbate CHF in severe LV dysfunction; may decrease myocardial contractility, but less so than verapamil. |
Dobutamine | Synthetic catecholamine and potent inotropic agent with predominant β-adrenergic receptor-stimulating effects that increase cardiac contractility in a dose-dependent manner, accompanied by a decrease in LV filling pressures. | Severe systolic heart failure | 5–20 mcg/kg/min | | Hemodynamic end points rather than specific dose is goal. Elderly have significantly reduced response. May induce or exacerbate myocardial ischemia with increases in heart rate. |
Flecainide | Potent sodium channel blocker with significant conduction-slowing effects | AF/flutter, ventricular arrhythmias and supraventricular arrhythmias without structural heart disease, ectopic atrial heart disease, AV nodal reentrant tachycardia, SVTs associated with an accessory pathway, including preexcited AF | 2 mg/kg at 10 mg/min (IV use not approved in the United States) | | Should not be used in patients with impaired LV function, or when coronary artery disease is suspected. |
Ibutilide | Short-acting antiarrhythmic, prolongs the action potential duration and increases refractory period | Acute conversion or adjunct to electrical cardioversion of AF/flutter of short duration | In patients >60 kg, 1 mg (10 mL) over 10 min; a second similar dose may be repeated in 10 min. In patients <60 kg, initial dose is 0.01 mg/kg | | Patients should be monitored for arrhythmias for 4–6 h, and longer in those with hepatic dysfunction. |
Magnesium | Hypomagnesemia associated with arrhythmias, cardiac insufficiency, and sudden death; can precipitate refractory VF; can hinder K+ replacement | Torsades de pointes with prolonged QT, even with normal serum levels of magnesium | 1–2 g in 50–100 mL D5W over 15 min | 500 mg/mL–IV/IO: 25–50 mg/kg; maximum dose: 2 g per dose | Rapid IV infusion for torsades de pointes or suspected hypomagnesemia not recommended in cardiac arrest except when arrhythmia suspected. |
Propafenone | Significant conduction slowing and negative inotropic effects. Nonselective β-adrenergic blocking properties | AF/flutter, ventricular arrhythmias and supraventricular arrhythmias without structural heart disease, ectopic atrial heart disease, AV nodal reentrant tachycardia, SVTs associated with an accessory pathway | 2.0 mg/kg at 10 mg/min (IV use not approved in the United States) | | Should be avoided with impaired LV function or when CAD suspected. |
Sotalol | Prolongs action potential duration and increases cardiac tissue refractoriness. Nonselective β-adrenergic blocking properties | Preexcited AF/flutter, ventricular and supraventricular arrhythmias | 1.0–1.5 mg/kg at a rate of 10 mg/min | | Limited by need to be infused slowly. Avoid in patients with prolonged QT. |