What medications can be used to treat tachycardia in patients who cannot take beta blockers (beta-adrenergic blocking agents)?

Alternative Medications for Tachycardia When Beta Blockers Are Contraindicated

Calcium channel blockers (diltiazem or verapamil) are the first-line alternatives to beta blockers for most supraventricular tachycardias, with class IC antiarrhythmics (flecainide or propafenone) reserved for patients without structural heart disease. 1

Acute Treatment Options

First-Line Alternatives

• Intravenous diltiazem or verapamil are reasonable for acute treatment of supraventricular tachycardia (SVT), including AVNRT and junctional tachycardia, with conversion rates exceeding 90% 1, 2
• These nondihydropyridine calcium channel blockers are equally efficacious as adenosine for converting SVT to sinus rhythm, without the transient adverse effects like flushing or chest discomfort 2, 3
• Intravenous procainamide is also reasonable for acute treatment, particularly when combined with calcium channel blockers 1

Specific Considerations by Arrhythmia Type

• For multifocal atrial tachycardia (MAT): Intravenous verapamil can terminate the arrhythmia with moderate success (converted 8 of 16 patients in one study) or at minimum slow the ventricular response 1
• For junctional tachycardia: Intravenous diltiazem, procainamide, or verapamil are reasonable when beta blockers cannot be used 1

Ongoing Management Options

Hierarchical Approach to Chronic Therapy

First-tier alternatives:

• Oral diltiazem or verapamil are reasonable for ongoing management of SVT, AVNRT, junctional tachycardia, and MAT 1
• These agents are particularly useful in patients with pulmonary disease who cannot tolerate beta blockers, as verapamil does not exacerbate pulmonary conditions 1

Second-tier alternatives (for patients without structural or ischemic heart disease):

• Flecainide (100-300 mg/day) or propafenone (450-900 mg/day) demonstrate high efficacy, with 86-93% probability of effective treatment at 12 months 1
• Critical contraindication: These class IC agents are absolutely contraindicated in patients with structural heart disease or ischemic heart disease due to proarrhythmia risk 1

Third-tier alternatives (when first and second-tier options fail or are contraindicated):

• Sotalol (80-160 mg twice daily) may be reasonable and can be used in patients with structural heart disease, unlike flecainide/propafenone 1
• Dofetilide may be reasonable for patients with structural or ischemic heart disease when other options have failed, with 50% remaining free of SVT at 6 months 1
• Amiodarone may be considered as a last resort given significant long-term toxicity concerns, reserved for patients unresponsive to all other agents 1
• Digoxin may be reasonable for SVT without pre-excitation, though evidence is limited and toxicity risk requires caution, particularly with renal dysfunction; target levels <0.8 ng/mL are optimal 1

Critical Safety Considerations

Contraindications and Precautions

• Calcium channel blockers should be avoided in:

  • Severe conduction abnormalities or sinus node dysfunction 1
  • Acute decompensated heart failure or hemodynamic instability 1
  • Pre-excitation syndromes (Wolff-Parkinson-White) where they may accelerate ventricular response 1

• When administering diltiazem or verapamil intravenously: Give over 20 minutes to minimize hypotension risk 2

Proarrhythmia Monitoring

• Sotalol and dofetilide require careful QT interval monitoring due to torsades de pointes risk 1
• Amiodarone requires monitoring for QT prolongation, thyroid dysfunction, pulmonary toxicity, and hepatotoxicity 4
• Amiodarone is FDA-indicated for ventricular arrhythmias but used off-label for SVT management 4

Special Populations

Pregnancy

• For AVNRT in pregnancy, vagal maneuvers and adenosine remain first-line, with electrical cardioversion for hemodynamically unstable patients 2

Pulmonary Disease

• Verapamil or diltiazem are preferred over beta blockers in patients with severe pulmonary disease, particularly bronchospasm 1

Common Pitfalls to Avoid

• Do not use flecainide or propafenone without first excluding structural heart disease or ischemic heart disease through appropriate imaging 1
• Avoid rhythm misidentification: Calcium channel blockers given for wide-complex tachycardia of ventricular origin can cause cardiovascular collapse 3
• Monitor digoxin levels closely when used, as levels >1.2 ng/mL are associated with worse outcomes 1
• Remember drug interactions: Amiodarone significantly increases digoxin levels (by 70% after one day) and warfarin effect (doubles prothrombin time), requiring dose reductions 4