What is the recommended bolus dose of intravenous (IV) metoprolol (Lopressor)?

From the Guidelines

The recommended IV metoprolol bolus dose is 5 mg administered over 1 to 2 minutes, which can be repeated every 5 minutes for a total initial dose of 15 mg. This dosing regimen is based on the guidelines for the management of patients with unstable angina/non-ST-elevation myocardial infarction, as outlined in the 2012 ACCF/AHA focused update incorporated into the ACCF/AHA 2007 guidelines 1. It is essential to note that early aggressive beta blockade poses a substantial net hazard in hemodynamically unstable patients and should be avoided, especially in those with cardiogenic shock, heart failure, or hypotension.

When administering IV metoprolol, it is crucial to monitor the patient's heart rate and blood pressure closely, as the medication can cause bradycardia, hypotension, and heart block 1. The patient's blood pressure and heart rate should be checked before each dose, and the medication should be held if systolic blood pressure falls below 100 mmHg or heart rate below 60 beats per minute.

Key considerations for IV metoprolol administration include:

• Starting with a low dose of 5 mg and titrating up to a maximum total dose of 15 mg
• Administering the dose over 1 to 2 minutes to minimize the risk of adverse effects
• Monitoring the patient's heart rate and blood pressure closely during and after administration
• Avoiding use in patients with cardiogenic shock, heart failure, or hypotension
• Transitioning to oral metoprolol once the patient is stable, with a typical maintenance dose of up to 100 mg twice daily 1.

From the FDA Drug Label

DOSAGE & ADMINISTRATION Myocardial Infarction Early Treatment During the early phase of definite or suspected acute myocardial infarction, initiate treatment with metoprolol tartrate as soon as possible after the patient’s arrival in the hospital. Such treatment should be initiated in a coronary care or similar unit immediately after the patient’s hemodynamic condition has stabilized Begin treatment in this early phase with the intravenous administration of three bolus injections of 5 mg of metoprolol tartrate injection each; give the injections at approximately 2-minute intervals. The recommended iv metoprolol bolus dose is 5 mg, given as three bolus injections, with each injection administered at approximately 2-minute intervals, for a total dose of 15 mg 2.

From the Research

IV Metoprolol Bolus

• The ideal bolus dose of IV metoprolol is not explicitly stated in the provided studies, but the dosage used in various studies can be referenced.
• In the study 3, the dosage of metoprolol was 1 to 3 mg/h in the intravenous group.
• In the study 4, the median dose of initial intervention was 5 [5-5] mg for metoprolol.
• It is essential to note that the dosage of metoprolol may vary depending on the patient's condition, heart rate, and other factors, and should be adjusted accordingly.
• The studies 5, 6, and 7 do not provide specific information on the bolus dose of IV metoprolol.

Administration and Efficacy

• The study 3 suggests that intravenous administration of metoprolol is more effective than oral administration in preventing atrial fibrillation after cardiac surgery.
• The study 4 compares the hemodynamic effects of intravenous push diltiazem and metoprolol for atrial fibrillation rate control, and found that both agents caused similar systolic blood pressure reduction and hypotension.
• The studies 5, 6, and 7 provide information on the efficacy and safety of metoprolol in various conditions, including hypertension, heart failure, and atrial fibrillation, but do not specifically address the bolus dose of IV metoprolol.

Safety and Tolerability

• The studies 4 and 3 report that metoprolol is generally well-tolerated, with few adverse effects.
• The study 7 notes that some patients may experience side effects such as bradycardia, hypotension, dyspnea, fatigue, and dizziness, which may limit the ability to titrate to a higher dose of beta-blockers.
• It is essential to monitor patients closely for potential adverse effects when administering IV metoprolol, and to adjust the dosage accordingly.