What is the oral metoprolol (beta-blocker) dose for supraventricular tachycardia (SVT)?

Oral Metoprolol Dosing for Supraventricular Tachycardia (SVT)

For oral management of SVT, metoprolol should be administered at a dose of 25-100 mg twice daily, with careful titration based on heart rate response and symptom control. 1

Acute Management vs. Ongoing Management

Acute Management:

1. First-line options:

   • Vagal maneuvers (Class I, LOE B-R) 1
   • Adenosine 6 mg IV rapid bolus, followed by 12 mg if needed (Class I, LOE B-R) 1

2. If first-line fails:

   • IV beta-blockers (including metoprolol) are reasonable for hemodynamically stable SVT (Class IIa, LOE C-LD) 1
   • IV metoprolol: 5 mg over 1-2 minutes, repeated as required every 5 minutes up to maximum dose of 15 mg 1

Ongoing Management (Oral Therapy):

• Oral beta-blockers (including metoprolol) are first-line for symptomatic SVT without ventricular pre-excitation (Class I, LOE B-R) 1
• Metoprolol tartrate: 25-100 mg twice daily
• Metoprolol succinate: 50-200 mg once daily

Clinical Considerations

Efficacy

• Beta-blockers work by antagonizing sympathetic tone in nodal tissue, slowing conduction through the AV node 1
• Studies show metoprolol can effectively control ventricular rate in SVT and may convert some patients to sinus rhythm 2, 3
• In one study, IV metoprolol successfully reduced ventricular rate by >15% in 69% of patients with supraventricular tachyarrhythmias 3

Contraindications

• Avoid in patients with:
  • Asthma or obstructive airway disease
  • Decompensated heart failure
  • Significant bradycardia or heart block
  • Pre-excited atrial fibrillation or flutter 1

Cautions

• May cause hypotension, bradycardia, and worsening heart failure 1
• Start with lower doses in elderly patients and those with renal or hepatic impairment
• Monitor vital signs and symptoms during dose titration

Alternative Oral Agents

If metoprolol is ineffective or contraindicated, consider:

1. Non-dihydropyridine calcium channel blockers:

   • Diltiazem: 120-360 mg daily in divided doses
   • Verapamil: 120-480 mg daily in divided doses 1

2. Other options (if beta-blockers and calcium channel blockers fail):

   • Flecainide or propafenone (in patients without structural heart disease) (Class IIa, LOE B-R) 1
   • Sotalol (Class IIb, LOE B-R) 1
   • Dofetilide (Class IIb, LOE B-R) 1
   • Amiodarone (Class IIb, LOE C-LD) 1

Monitoring and Follow-up

• Assess heart rate and blood pressure response within 1-2 weeks of starting therapy
• Titrate dose to achieve adequate rate control and symptom relief
• Consider electrophysiological study with ablation for definitive treatment in patients with recurrent symptomatic SVT 1

Common Pitfalls

• Avoid abrupt discontinuation of beta-blockers as this can lead to rebound tachycardia and worsening symptoms 4
• Do not use beta-blockers in pre-excited atrial fibrillation or flutter as they may paradoxically increase ventricular rate 1
• Avoid combination with other AV nodal blocking agents that have longer duration of action, as profound bradycardia can develop 1

Remember that while oral metoprolol is effective for ongoing management of SVT, catheter ablation provides definitive treatment and should be considered for patients with recurrent symptomatic episodes 1.