Can metoprolol (beta-blocker) be used as a continuous infusion for Supraventricular Tachycardia (SVT)?

Metoprolol for SVT: Continuous Infusion Therapy

Metoprolol should not be administered as a continuous infusion for SVT treatment, but rather as intermittent IV boluses followed by oral therapy if needed for ongoing management. 1

Evidence-Based Approach to Metoprolol in SVT

Recommended Administration Method

• According to the 2015 ACC/AHA/HRS guidelines, metoprolol for SVT should be administered as:
  • Initial dose: 2.5-5.0 mg IV bolus over 2 minutes
  • May repeat: 2.5-5.0 mg IV bolus in 10 minutes, up to 3 doses total 1
  • For ongoing management: Convert to oral therapy (25 mg BID initially, maximum 200 mg BID) 1

Efficacy for SVT

Metoprolol is effective for:

• Rate control in various SVT types 2
• Conversion to sinus rhythm in some cases (reported in 3 out of 6 patients with paroxysmal SVT) 3
• Specific effectiveness in multifocal atrial tachycardia (MAT) 1

Clinical Considerations and Contraindications

Precautions When Using Metoprolol for SVT

• Absolute contraindications:

  • AV block greater than first degree or SA node dysfunction (without pacemaker)
  • Decompensated systolic heart failure
  • Cardiogenic shock
  • Severe reactive airway disease 1

• Relative contraindications/use with caution:

  • Hypotension (most common adverse effect) 2
  • Mild-moderate reactive airway disease
  • Renal dysfunction
  • Concomitant use of other drugs with SA/AV nodal-blocking properties 1

Alternative Approaches for SVT Management

First-line Treatments

1. Vagal maneuvers (Class I recommendation) 1
2. IV adenosine (Class I recommendation) 1
3. IV diltiazem or verapamil (Class IIa) 1

When Beta-Blockers Are Preferred

• In hemodynamically stable patients without contraindications
• In specific SVT types like MAT after correction of underlying causes 1
• During pregnancy (metoprolol is preferred over atenolol) 1

Practical Administration Guidelines

Monitoring During Administration

• Continuous cardiac monitoring
• Frequent blood pressure measurements
• Respiratory status assessment
• Have resuscitation equipment available

Management of Adverse Effects

• For hypotension: IV fluids, position change, vasopressors if severe
• For bradycardia: Atropine, temporary pacing if severe
• For bronchospasm: Bronchodilators, discontinue metoprolol

Conclusion

While metoprolol is effective for SVT management as intermittent IV boluses and oral therapy, there is no evidence supporting its use as a continuous infusion in the guidelines. For patients requiring ongoing IV therapy for SVT, esmolol (with its shorter half-life) would be a more appropriate beta-blocker for continuous infusion at 50-300 mcg/kg/min 1.