What is the maximum daily dose of intravenous (IV) metoprolol?

Maximum Daily Dose of Intravenous Metoprolol

The maximum daily dose of intravenous metoprolol is 15 mg, administered as three 5 mg boluses over 2 minutes each, with each dose separated by 5 minutes. 1

Dosing Guidelines for IV Metoprolol

According to the 2014 AHA/ACC/HRS guidelines for the management of atrial fibrillation, the recommended intravenous administration of metoprolol tartrate is:

• 2.5-5.0 mg IV bolus over 2 minutes
• Up to 3 doses can be administered (for a total maximum of 15 mg)
• Each dose should be separated by appropriate intervals (typically 5 minutes) 1

This dosing regimen is primarily used for:

• Rate control in atrial fibrillation
• Management of tachyarrhythmias
• Acute coronary syndromes when beta blockade is indicated

Administration Considerations

When administering IV metoprolol, several important considerations should guide clinical decision-making:

Monitoring Requirements

• Continuous ECG monitoring during administration
• Frequent blood pressure checks
• Heart rate monitoring
• Auscultation for rales and bronchospasm 1

Contraindications

IV metoprolol should be avoided in patients with:

• Signs of heart failure or pulmonary edema
• Evidence of a low-output state (e.g., oliguria)
• Significant sinus bradycardia (heart rate <50 beats/min)
• Hypotension (systolic blood pressure <90 mm Hg)
• High-grade AV block
• Cardiogenic shock or at high risk for shock 1

Risk Factors for Cardiogenic Shock

Particular caution is needed in patients with:

• Age >70 years
• Systolic BP <120 mm Hg
• Heart rate >110 bpm or <60 bpm
• Increased time since symptom onset 1, 2

Transition to Oral Therapy

After successful IV administration, patients who tolerate the total 15 mg IV dose can be transitioned to oral therapy:

• Begin oral therapy 15 minutes after the last IV dose
• Initial oral dose: 25-50 mg every 6 hours for 48 hours
• Maintenance dose: up to 100 mg twice daily 1

Special Populations

For patients with concerns about beta-blocker tolerance:

• Consider starting with a lower dose (e.g., 2.5 mg IV)
• Use shorter-acting agents like esmolol for initial testing
• For patients with mild wheezing or history of COPD, consider reduced doses (e.g., 12.5 mg oral metoprolol) rather than complete avoidance 1

Clinical Pearls

1. The target resting heart rate when using metoprolol for rate control is 50-60 beats per minute, unless limiting side effects occur 1

2. In patients with atrial fibrillation, a heart rate control strategy (resting heart rate <80 bpm) is reasonable for symptomatic management 1

3. For patients with asymptomatic atrial fibrillation and preserved LV function, a more lenient rate control strategy (resting heart rate <110 bpm) may be reasonable 1

4. Always have resuscitation equipment readily available when administering IV beta-blockers due to the risk of profound bradycardia or hypotension