Drug (Class) |
Indication |
Dose/Administration Therapeutic Level/Half-Life |
Side Effects |
Comments |
Adenosine (Adenocard) |
First-line therapy to terminate AV nodal active SVT (AVNRT, CMT) Can be diagnostic in AV nodal passive rhythms by causing AV block and revealing underlying atrial mechanism, and in wide complex tachycardias of uncertain origin VT arising in the RVOT that is due to after depolarizations may respond to adenosine |
6 mg given very rapidly IV followed by rapid saline flush May follow with 12 mg if needed and repeat 12 mg if no effect Half-life = 9 seconds |
Acute onset of AV block usually lasting a few seconds. May result in brief period of asystole or bradycardia that is not responsive to atropine Torsades can occur in patients who are susceptible to bradycardia-dependent arrhythmias Flushing, hot flash, acute dyspnea lasting a few seconds, chest pressure Can precipitate bronchoconstriction in asthmatic patients |
Very short half-life so side effects are transient Warn patients about side effects before giving drug—especially dyspnea. It may be helpful to have patient take a deep breath while injecting drug to ↓ dyspneic sensation Should not be used when arrhythmia is known to be atrial fib or flutter Monitor ECG during administration and be prepared for cardioversion May accelerate accessory pathway conduction and should not be used when antegrade conduction is occurring over accessory pathway May rarely accelerate ventricular rate in atrial flutter Drug interactions: Theophylline (and related drugs) and caffeine antagonize effects of adenosine and make it ineffective Dipyridamole and carbamazepine potentiate effects of adenosine |
Amiodarone (Cordarone) (Classified as a class III antiarrhythmic but has powerful class I sodium channel blocking effects, moderate class II β-blocking effects, and weak class IV calcium channel blocking effects) |
Life-threatening ventricular arrhythmias: recurrent VF, recurrent hemodynamically unstable VT Also widely used for: Conversion of atrial fib to sinus rhythm and maintenance of NSR Slowing conduction through accessory pathways in atrial fib or CMT |
PO: 800-1,600 mg q.d. for 1-3 weeks, then 400-800 mg q.d. for 1-3 weeks Maintenance: 100-400 mg/day May be given as single daily dose or bid if GI intolerance occurs IV: 1,000 mg over first 24 hours given as follows: First rapid infusion: 150 mg over first 10 minutes (15 mg/min) (Add 3 mL [150 mg] to 100 mL D5W) Infuse 100 mL over 10 minutes Followed by slow infusion: 360 mg over next 6 hours (1 mg/min) (Add 18 mL [900 mg] to 500 mL D5W) Infuse at 33.6 mL/h Maintenance infusion: 540 mg over next 18 hours (0.5 mg/min) (Decrease rate of slow loading infusion to 0.5 mg/min) Infuse at 16.8 mL/h May continue with 0.5 mg/min for 2-3 weeks if needed. Central line recommended for long-term infusions If breakthrough VT occurs, may give supplemental doses of 150 mg over 10 min. (150 mg added to 100 mL D5W) |
Bradycardia, heart block Proarrhythmia (VF, incessant VT, torsades) Hypotension with IV form Pulmonary fibrosis, corneal microdeposits, photosensitivity, blue skin, thyroid dysfunction (hypo and hyper), liver dysfunction Tremor, malaise, fatigue, GI upsets, dizziness, poor coordination, peripheral neuropathy, involuntary movements Liver enzyme elevations are common but occur in patients with MI, HF, shock, multiple defibrillations, and so forth. It is unknown if elevations in liver enzymes are due to amiodarone or to associated conditions commonly present in these patients Hepatocellular necrosis has occurred in patients who received IV amiodarone at rates higher than recommended |
Give with meals to ↓ GI intolerance Baseline chest x-ray, renal, liver, thyroid, and pulmonary function tests Takes several weeks to achieve therapeutic blood levels and for effects to decrease after stopping drug Is not dialyzable. Monitor K+ and Mg2+ levels Monitor QTc Drug interactions: Additive proarrhythmic effects with many drugs (1A antiarrhythmics, phenothiazines, tricyclic antidepressants, thiazide diuretics, sotalol) ↑ Protime with coumadin ↑ Serum levels of digoxin, quinidine, procainamide, cyclosporine May double flecainide level Cimetidine ↑ serum amiodarone levels Cholestyramine and phenytoin (Dilantin) ↓ serum amiodarone levels Additive effects on ↓ HR and ↓ AV conduction with β-blockers and Ca2+ blockers |
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IV to PO transition: |
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Special precautions with IV form: Physically incompatible with aminophylline, heparin, cefamandole, cefazolin, mezlocillin, sodium bicarbonate Must be delivered using a volumetric pump (not drop counter) because drop size is altered by drug |
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Duration of IV |
PO dose |
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<1 week |
800-1600 mg q.d. |
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1-3 weeks |
600-800 mg q.d. |
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>3 weeks |
400 mg q.d. |
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Therapeutic level = 0.5-2 mcg/mL Very long half-life (26-107 days; average 53 days) |
Atenolol (Tenormin) (Cardioselective β-blocker) |
Ventricular rate control in atrial fib/flutter Slow conduction through AV node in AVNRT and CMT |
Initial dose: 12.5-25 mg PO q.d. Maintenance dose: 50-100 mg PO q.d. IV: 5 mg over 5 minutes, may repeat in 5 minutes Half-life = 6-7 hours |
Hypotension, bradycardia, AV block. Diarrhea, wheezing, HF |
Cardioselective β-blocker used primarily for hypertension and angina Drug interactions: Additive effects on HR, AV conduction, BP, and ↑ potential for HF when given with negative inotropic drugs, Ca2+ blockers, digoxin |
Atropine (Anticholinergic, parasympatholytic) |
Treatment of symptomatic bradycardia (sinus, junctional, AV block) and asystole |
Symptomatic bradycardia: 0.5 mg IV. May repeat q 3-5 minutes to a total of 3 mg Asystole: 1 mg IV, repeat q 3-5 minutes to a total vagolytic dose of 0.04 mg/kg May be given down ET tube during cardiac arrest if no IV available: use 2-2.5 mg Half-life = 2-5 hours |
CV: tachycardia, chest pain, VT/fibrillation (rare) CNS: drowsiness, confusion, dizziness, insomnia, nervousness GI: dry mouth, ↓ GI motility, constipation, nausea Other: urinary retention, hot flushed skin, rash |
Doses (0.5 mg may cause paradoxical bradycardia Causes pupils to dilate (significant when checking pupils during cardiac arrest situation) Drug interactions: Incompatible with aminophylline, metaraminol, norepinephrine, pentobarbitol, sodium bicarbonate |
Digoxin |
Ventricular rate control in atrial fib/flutter Rarely used as an antiarrhythmic anymore Used as an inotropic agent in HF |
PO loading dose: 0.5-1 mg divided into three or four doses at 6-8-hour intervals PO maintenance dose: 0.125-0.5 mg q.d. IV loading dose: 0.5-1 mg divided into three or four doses given at 4-8-hour intervals Therapeutic level = 0.8-2 ng/mL Half-life = 36-48 hours |
CV: bradycardia, AV block Digoxin toxicity: sinus exit block, AV block, AT with block, bidirectional VT, fascicular tachycardia, accelerated junctional rhythm, regularization of ventricular response to atrial fib Visual disturbances (halo vision), anorexia, nausea, vomiting, malaise, headache, weakness, disorientation, seizures |
Contraindicated in patients with WPW Digoxin toxicity is more common in the presence of hypokalemia, renal failure, pulmonary or thyroid disease, and in older people Drug interactions: The following drugs ↓ digoxin levels: cholestyramine, antacids, kaopectate, neomycin, sulfasalazine, para-aminosalicylate The following drugs ↑ digoxin levels: Erythromycin, tetracycline, quinidine, amiodarone, verapamil, spironolactone, nicardipine, indomethacin |
Diltiazem (Cardizem) (Calcium channel blocker: nondihydropyridine, “heart rate lowering” Ca2+ blocker) |
Ventricular rate control in atrial fib/flutter Slow conduction through AV node in AVNRT and CMT |
120-360 mg/day in divided doses IV: 0.25 mg/kg bolus over 2 minutes If needed, repeat with 0.35 mg/kg over 2 minutes IV infusion: 5-15 mg/h Therapeutic level = 50-200 ng/mL Half-life = 4-6 hours |
Bradycardia, heart block, HF, hypotension, flushing, angina, syncope, insomnia, ringing ears, edema, headache, nausea Less depression of contractility than with verapamil but watch for HF |
Contraindicated in patients with accessory pathways (WPW, short PR syndrome) Drug interactions: Additive effects on HR, AV conduction, BP, and ↑ potential for HF when given with negative inotropic drugs, β-blockers, digoxin |
Disopyramide (Norpace) (Class IA antiarrhythmic) |
Used to prevent recurrence of VT or VF Effective in preventing atrial fib and flutter Slows conduction through accessory pathways |
Total daily dose = 400-800 mg in divided doses, usually 150 mg q 6 hours SR form = 300 mg q 12 hours Therapeutic level = 3-6 mcg/mL Half-life = 4-10 hours |
Anticholinergic effects: dry mouth, urinary retention, constipation, precipitation or exacerbation of glaucoma CV: marked negative inotropic effects, HF, prolongs QT interval, proarrhythmic (less than quinidine or procainamide), ↑ SVR |
Monitor QT interval and watch for torsades Drug Interactions: May potentiate effect of coumadin Additive negative inotropic effects with β-blockers or Ca2+ blockers. Phenobarbitol, dilantin, rifampin ↓ disopyramide levels. Quinidine ↑ disopyramide level |
Dofetilide (Tikosyn) (Class III antiarrhythmic) |
Conversion of atrial fibrillation or flutter to NSR and maintenance of NSR after conversion |
Dose based on creatinine clearance: if normal renal function, 500 mcg b.i.d. If abnormal renal function, 250 mcg b.i.d. Do not give if creatinine clearance <20 mL/min Half-life = 9.5 hours |
TdP (up to 3% incidence), usually occurs within 3 days after initiating therapy Has no negative inotropic effects and does not lower BP |
Patient must be on telemetry during initiation of therapy or with increase in dosage (recommendation is for 3 days monitoring) Monitor QT interval every 2-3 hours: if QTc increases >15% or if QTc is >500 milliseconds, reduce dose. If QTc after second dose is >500 milliseconds, drug should be discontinued Drug Interactions: Drugs that increase dofetilide levels include verapamil, ketoconazole, cimetidine, macrolide antibiotics, ritonavir, prochlorperazine, megestrol Maintain normal K+ and Mg2+ levels |
Epinephrine (Adrenalin) |
Treatment of any cardiac arrest situation requiring CPR: VF, pulseless VT, asystole, PEA |
1 mg IV bolus every 3-5 minutes during resuscitation efforts May be given by way of ET tube if IV access not available: use 2-2.5 mg May be infused at 2-10 mcg/min to maintain BP during symptomatic bradycardia |
CV: tachycardia, hypertension, arrhythmias, angina CNS: restlessness, headache, tremor, stroke Other: nausea, ↓ urine output, transient tachypnea |
Drug Interactions: Has potential to cause arrhythmias when given with digoxin, other sympathomimetic agents Physically incompatible with aminophylline, ampicillin, cephapirin, sodium bicarbonate, and other alkaline solutions |
Esmolol (Brevibloc) (Cardioselective β-blocker) |
Rapid control of ventricular rate in atrial fib/flutter |
Loading infusion: 500 mcg/kg/min for 1 minute Maintenance infusion: 50-100 mcg/kg/min Use dosing chart that comes with drug. β-Blocking plasma concentration = 0.15-1 mcg/mL Half-life = 9 minutes |
Hypotension, dizziness, diaphoresis, nausea |
Short half-life so effects reversed within 10-20 minutes after stopping drug |
Flecainide (Tambocor) (Class IC antiarrhythmic) |
In absence of structural heart disease: Conversion of atrial fib to sinus rhythm and maintenance of NSR Treatment of SVT: AVNRT, CMT Slow conduction through accessory pathways in atrial fib or CMT Life-threatening ventricular arrhythmias (sustained VT) |
100-200 mg PO q 12 hours Therapeutic level = 0.2-1 mcg/mL (Plasma levels do not correlate with efficacy, but incidence of CV toxicity greater when levels >1 mcg/mL) Half-life = 12-27 hours |
CV: marked proarrhythmia, marked negative inotropic effects (HF), bradycardia, heart block CNS: blurred vision, dizziness, flushing, ringing ears, drowsiness, headache. Other: bad taste, constipation, edema, abdominal pain |
Drug interactions: May increase digoxin level Additive effects on HR, AV conduction, BP, and ↑ potential for HF when given with negative inotropic drugs, Ca2+ blockers, digoxin Incompatible with sodium bicarbonate, Lasix, Valium, thiopental Higher mortality rate in post-MI patients when studied in CAST. Safest in patients with normal LV function Should not be used in patients with recent MI Prolongs QT interval, potential for proarrhythmia (TdP) Monitor for HF Full therapeutic effect may take up to 5 days Drug Interactions: ↑ digoxin levels. Cimetidine, amiodarone, propranolol increase flecainide levels Additive negative inotropic effects with β-blockers, Ca2+ blockers, disopyramide |
Ibutilide (Corvert) (Class III antiarrhythmic) |
Conversion of atrial fib or flutter to sinus |
IV infusion of 1 mg over 10 minutes May repeat same dose in 10 minutes if needed In patients <60 kg: 0.01 mg/kg Half-life = 6 hours |
Hypotension, VT, torsades, bundle-branch block, AV block, nausea, headache |
Prolongs QT interval: up to 6% incidence of torsades. Proarrhythmia usually occurs within 40 minutes. Monitor ECG continuously during administration and at least 4 hours after Conversion to NSR usually occurs within 20-30 minutes of infusion Drug interactions: Do not give other class I or class III agents within 4 hours |
Lidocaine (Xylocaine) (Class IB antiarrhythmic) |
Treatment of ventricular arrhythmias: VT, VF Effective for PVC suppression but PVC suppression not usually recommended |
For VT: 1 mg/kg IV bolus over 3 minutes followed by infusion at 2-4 mg/min. Repeat bolus of 0.5-0.75 mg/kg in 10 minutes to maintain therapeutic level. May repeat to total of 3 mg/kg For VF or pulseless VT: 1.5 mg/kg IV bolus. May repeat with same amount and follow with infusion at 2-4 mg/min May be given down ET tube during cardiac arrest if no IV available. Therapeutic level = 1.4-5 mcg/mL Half-life of bolus = 10 minutes Half-life once therapeutic level reached = 1.5-2 hours |
Side effects relatively rare CNS: lightheadedness, dizziness, tremor, agitation, tinnitus, blurred vision, convulsions, respiratory depression and arrest CV: bradycardia, asystole, hypotension, shock |
↓ Dose to half if liver disease or low liver blood flow (shock) Drug Interactions: β-Blockers and cimetidine increase lidocaine levels Glucagon and isoproterenol may increase liver blood flow and ↓ lidocaine levels |
Magnesium |
May be useful for treatment or prevention of both supraventricular and ventricular arrhythmias after MI or cardiac surgery. Treatment of choice for TdP and may be useful in VF or pulseless VT refractory to other drugs |
1-2 g diluted in 10 mL D5W over 1-2 minutes. May be given IV push for VF or torsades Infusion of 0.5-1 g/h for up to 24 hours |
CV: hypotension, bradycardia, heart block, cardiac arrest CNS: weakness, drowsiness, peripheral neuromuscular blockade, absent deep tendon reflexes Other: ↓ respiratory rate, respiratory paralysis |
Drug Interactions: CNS depression when used with general anesthetics, barbiturates, opiate analgesics Additive effects with neuromuscular blocking agents Incompatible with calcium, sodium bicarbonate, ciprofloxacin |
Metoprolol (Lopressor) (Cardioselective β-blocker) |
Ventricular rate control in atrial fib/flutter Slow conduction through AV node in AVNRT and CMT |
PO: 100-450 mg q.d. in divided doses IV: 5 mg q 2-5 minutes for three doses (used in acute MI) β-Blocking plasma concentration = 50-100 ng/mL Half-life = 3-7 hours |
Hypotension, bradycardia, AV block |
Drug interactions: Additive effects on HR, AV conduction, BP, and ↑ potential for HF when given with negative inotropic drugs, Ca2+ blockers, digoxin |
Mexiletine (Mexitil) (Class IB antiarrhythmic) |
Acute and chronic treatment of symptomatic VT Sometimes used in combination with Quinidine or sotalol to increase efficacy May be useful in congenital LQTS |
PO loading dose = 400 mg Maintenance dose = 100-300 mg q 8 hours. Up to 400 mg q 8 hours if needed and no intolerable side effects Therapeutic level = 0.5-2 mcg/mL Half-life = 10-17 hours |
GI: nausea, vomiting, heartburn, anorexia, diarrhea CNS: tremor, dizziness, ataxia, slurred speech, paresthesias, seizures, hallucinations, emotional instability, insomnia, memory impairment CV: bradycardia, hypotension, HF, proarrhythmia (rare compared to other agents) Other: thrombocytopenia, fever, rash, positive antinuclear antibody |
Often given in combination with other antiarrhythmics with increased effectiveness (quinidine, disopyramide, propafenone, amiodarone) Drug interactions: Phenobarbitol, dilantin, rifampin ↓ mexiletine levels Cimetidine ↑ mexiletine levels Mexiletine ↑ theophylline levels |
Procainamide (Pronestyl) (Class IA antiarrhythmic) |
Conversion of atrial fib to sinus and maintenance of NSR Treatment of AT, atrial flutter and fib Slows conduction through accessory pathways in WPW Treatment of monomorphic VT |
PO dose (regular release form): loading dose of 1,000-1,200 mg; maintenance dose 50 mg/kg/day in divided doses three to four times a day (never more than 6 hour between doses) SR forms: 750-1,500 mg q 6 hours IV loading dose: 17 mg/kg at 20 mg/min. If rapid loading is needed, give 100-mg doses over 5 minutes to total of 1g IV drip 2-4 mg/min Therapeutic level = 4-10 mcg/mL (may be as high as 5-32 mg/L to prevent sustained VT) Half-life = about 3.5 hours Active metabolite is NAPA: therapeutic level = 9-12 mg/L |
GI: nausea, vomiting, anorexia CV: bradycardia, heart block, proarrhythmia (less than that with quinidine). Prolongs QT interval Hypotension. With IV use CNS: headache, insomnia, dizziness, psychosis, hallucinations, depression Lupus-like syndrome with long-term use (15%-25% of patients who take drug >1 year) Other: rash, fever, swollen joints, agranulocytosis, pancytopenia |
Monitor QT interval, QRS width, PR. Monitor NAPA level (active metabolite) Watch for hypotension with IV use Drug Interactions: Amiodarone, cimetidine, ranitidine increase procainamide levels Alcohol ↓ procainamide levels Additive effects on conduction system disease when given with other class IA, class IC, tricyclic antidepressants, or Ca2+ blockers |
Propafenone (Rythmol) (Class IC antiarrhythmic, also has β-blocker effects) |
Conversion of atrial fib to sinus and maintenance of NSR Slow conduction through accessory pathways Life-threatening ventricular arrhythmias (sustained VT) |
150-300 mg t.i.d. Therapeutic level = 0.2-3 mcg/mL Half-life = 2-10 hours in normal metabolizers, up to 32 hours in slow metabolizers |
GI: nausea, anorexia, constipation, metallic taste CNS: dizziness, headache, blurred vision CV: HF, bradycardia, AV block, bundle-branch block, proarrhythmia |
Was not included in CAST but is same class as drugs shown to cause higher mortality post-MI Watch for proarrhythmia Drug interactions: ↑ digoxin levels. Potentiates coumadin Has mild β-blocker and Ca2+ blocker effects ↑ Cyclosporin levels Quinidine and cimetidine increase propafenone levels |
Propranolol (Inderal) (Noncardioselective β-blocker) |
Ventricular rate control in atrial fib/flutter Treatment of SVT (slow AV node conduction): AVNRT, CMT Effective in some types of VT: exercise induced, digitalis induced Effective in reducing incidence of VF and sudden death post-MI |
PO: 10-30 mg three to four times a day IV: 1-3 mg at rate of 1 mg/min β-Blocking plasma concentration = 50-100 ng/mL Half-life = 3-5 hours |
GI: nausea, vomiting, stomach discomfort, constipation, diarrhea CNS: dreams, hallucinations, insomnia, depression Other: bronchospasm, exacerbation of peripheral vascular disease, fatigue, hypoglycemia, impotence |
Drug interactions: Additive effects on HR, AV conduction, BP, and ↑ potential for HF when given with negative inotropic drugs, Ca2+ blockers, digoxin |
Quinidine (Class IA antiarrhythmic) |
Not used much anymore due to high incidence of proarrhythmia Conversion of atrial fib to NSR and maintenance of NSR May be used for other SVTs: AT, AVNRT, accessory pathways Has been used for VT |
Sulfate: 200-400 mg q 6-8 hours Gluconate: 324 mg SR tabs, 1-2 q 8-12 hours Therapeutic level = 2-6 mcg/mL Half-life = 7-9 hours |
GI: nausea, diarrhea, abdominal pain CV: hypotension, bradycardia, tachycardias, TdP, HF prolongs QTc interval, proarrhythmia CNS: cinchonism (tinnitus, hearing loss, confusion, delirium, visual disturbances, psychosis) |
Give with food. Monitor QT interval, QRS width, PR Watch for proarrhythmia (torsades) IV use rare (hypotension) Drug Interactions: ↑ Digoxin levels Increased bleeding when used with coumadin |
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Other: fever, headache, rashes, leukopenia, thrombocytopenia |
Dilantin, phenobarbital, rifampin, nifedipine, sodium bicarbonate, thiazide diuretics all ↓ quinidine levels Cimetidine, amiodarone, verapamil all increase quinidine levels |
Sotalol (Betapace) (Class III antiarrhythmic; and noncardioselective β-blocker) |
Maintenance of NSR after conversion from atrial fib/flutter. Not recommended for pharmacological conversion of atrial fib/flutter Treatment of SVT Slow conduction through accessory pathways Life-threatening VT, VF |
Should be used only in patients without heart disease or bradycardia when serum electrolytes are normal Contraindicated if baseline QTc >450 milliseconds or CrCl <40 mL/min. 80 mg b.i.d. × 3 days, then 160 mg b.i.d. × 3 days. Decrease dose or discontinue if QT prolongs to 500 milliseconds or more Maximum recommended dose is 160 mg b.i.d Therapeutic level = 1-4 mcg/mL (not clinically useful) Half-life = 8-17 hours with normal renal function; up to 6 days with severe renal failure |
CV: bradycardia, heart block, HF, proarrhythmia Other: bronchospasm, fatigue, weakness, GI symptoms, dizziness, dyspnea, hypotension |
Prolongs QT interval, potential for proarrhythmia. Monitor QT 2-4 hours after each dose when initiating therapy Watch for bradycardia, AV block, and new or worsening HF |
Verapamil (Calan) (Calcium channel blocker: nondihydropyridine “heart rate lowering” Ca2+ blocker) |
Ventricular rate control in atrial fib/flutter Slow conduction through AV node in AVNRT and CMT |
PO: 80-120 mg t.i.d. or q.i.d. IV: 2.5-5 mg over 2 minutes May repeat with 5-10 mg if needed Therapeutic level = 80-400 ng/mL Half-life = 3-7 hours |
Bradycardia, heart block, HF, hypotension, fatigue, headache, edema, constipation |
Contraindicated in patients with accessory pathways (WPW, short PR syndrome) Drug interactions: Additive effects on HR, AV conduction, BP, and ↑ potential for HF when given with negative inotropic drugs, Ca2+ blockers, digoxin |
CAST, Cardiac Arrhythmia Suppression Trial; CMT, circus movement tachycardia using an accessory pathway; ET, endotracheal, NAPA, N-acetylprocainamide; NSR, normal sinus rhythm, PEA, pulseless electrical activity, SVR, systemic vascular resistance, SR, sustained release. |
↑ = increases, ↓ = decreases. |