IV Metoprolol (Lopressor) Administration Protocol
Administer IV metoprolol as 2.5-5 mg slow IV bolus over 2 minutes, repeated every 5 minutes as needed, with a maximum total dose of 15 mg (three 5 mg boluses). 1, 2
Standard Dosing Protocol
For acute situations requiring IV metoprolol (hypertensive emergencies, acute coronary syndromes, atrial fibrillation with rapid ventricular response):
- Initial dose: 2.5-5 mg IV bolus administered slowly over 1-2 minutes 1, 2
- Repeat dosing: May repeat every 5 minutes based on hemodynamic response 1, 2
- Maximum total dose: 15 mg (three 5 mg boluses) 1, 2
- Onset of action: 1-2 minutes 1
- Duration of action: 5-8 hours 1
Critical Contraindications - Check Before Administration
Absolute contraindications that mandate withholding IV metoprolol: 1, 2
- Signs of heart failure, low output state, or decompensated heart failure 1
- Second or third-degree AV block (without functioning pacemaker) 1
- PR interval >0.24 seconds 1
- Systolic heart failure 1
- Active asthma or reactive airway disease 1
- Bradycardia (heart rate <60 bpm) 1
- Systolic blood pressure <120 mmHg 1
- Heart rate >110 bpm or <60 bpm 1
- Age >70 years with multiple risk factors for cardiogenic shock 1
Required Monitoring During Administration
Continuous monitoring must include: 1, 2
- Blood pressure monitoring at each dose 1, 2
- Heart rate monitoring continuously 1, 2
- Continuous ECG monitoring 1, 2
- Auscultation for new rales (pulmonary congestion) 1
- Auscultation for bronchospasm 1
Transition to Oral Therapy
After completing IV dosing: 2
- Timing: Initiate oral metoprolol tartrate 15 minutes after the last IV dose 2
- Initial oral dose: 50 mg every 6 hours for patients tolerating full IV dose (15 mg total) 2
- Continue for: 48 hours, then transition to maintenance dosing of 100 mg twice daily 2
- For patients with intolerance: Start 25-50 mg every 6 hours depending on degree of intolerance 2
Common Pitfalls to Avoid
Critical errors that increase adverse event risk: 1, 3
- Never administer the full 15 mg as a single rapid bolus - this significantly increases hypotension and bradycardia risk 3
- Never use in decompensated heart failure - wait until clinical stabilization 3
- Never use in pre-excited atrial fibrillation (WPW syndrome) - may paradoxically accelerate ventricular response 3
- Never give without checking for signs of cardiogenic shock risk - particularly in elderly patients or those with Killip class II-III 3
Administration Setting Requirements
IV metoprolol must be administered in a setting with intensive monitoring capabilities 2
- Coronary care unit or similar monitored setting 2
- Defibrillator readily available 3
- Capability for immediate intervention if hypotension or severe bradycardia develops 3
Primary Adverse Effects
Most common adverse effects requiring dose adjustment: 1