Intravenous Metoprolol Dosing for Patients Unable to Take Oral Medications
For patients unable to take oral medications, intravenous metoprolol tartrate should be administered as 5 mg boluses every 5 minutes as tolerated, up to a maximum of 3 doses (15 mg total), with careful titration to heart rate and blood pressure. 1, 2
Standard IV Metoprolol Dosing Protocol
- Administer metoprolol tartrate as three bolus injections of 5 mg each 2
- Give injections at approximately 2-minute intervals 2
- Monitor blood pressure, heart rate, and electrocardiogram during administration 2
- Maximum total IV dose: 15 mg 1, 2
Transition to Oral Therapy When Possible
- For patients who tolerate the full IV dose (15 mg), initiate metoprolol tartrate tablets 50 mg every 6 hours, 15 minutes after the last IV dose 2
- Continue oral dosing for 48 hours, then transition to maintenance dose of 100 mg orally twice daily 2
- For patients with partial intolerance to IV dosing, start with lower oral doses (25-50 mg every 6 hours) when oral administration becomes possible 2
Clinical Indications for IV Metoprolol
- Refractory hypertension requiring rapid control 1
- Ongoing myocardial ischemia 1
- Acute rate control in atrial fibrillation or flutter 1
- Early treatment of acute myocardial infarction 2
Contraindications and Precautions
- Avoid in patients with signs of heart failure 1
- Avoid in patients with low output states 1
- Avoid in patients at increased risk for cardiogenic shock (age >70 years, systolic BP <120 mmHg, heart rate >110 bpm or <60 bpm) 1
- Avoid in patients with prolonged first-degree or high-grade AV block 1
- Avoid in patients with reactive airways disease 1
- Use with caution in patients with hepatic impairment (lower doses may be required) 2
Monitoring During IV Administration
- Continuous ECG monitoring 2
- Frequent blood pressure checks 1
- Heart rate monitoring 2
- Auscultation for rales and bronchospasm 1
- Monitor for signs of worsening heart failure 1
Special Populations
- Elderly patients: Start with lower doses due to greater frequency of decreased hepatic, renal, or cardiac function 2
- Hepatic impairment: Initiate at low doses with cautious gradual titration due to likely substantial increase in metoprolol blood levels 2
- No dose adjustment required for patients with renal impairment 2
Clinical Pearls
- IV metoprolol should be administered in a setting with intensive monitoring 2
- The onset of action is approximately 5 minutes after IV administration 1
- In patients with Wolff-Parkinson-White syndrome and tachycardia with ventricular pre-excitation, IV beta-blockers are contraindicated as they may facilitate antegrade conduction along the accessory pathway during AF 1
- For patients who cannot tolerate oral or IV administration, rectal administration may be considered as an alternative route, though further research is needed to define exact dosing 3