From the Guidelines
When converting from oral metoprolol to intravenous (IV) metoprolol, the recommended approach is to administer IV metoprolol in 5-mg increments by slow intravenous administration (5 mg over 1 to 2 min), repeated every 5 min for a total initial dose of 15 mg, as this method is supported by the 2013 ACCF/AHA guidelines 1. The choice of beta blocker for an individual patient is based primarily on pharmacokinetic and side effect criteria, as well as on physician familiarity.
- Key considerations for metoprolol conversion include:
- Intravenous metoprolol may be given in 5-mg increments by slow intravenous administration (5 mg over 1 to 2 min), repeated every 5 min for a total initial dose of 15 mg.
- In patients who tolerate the total 15-mg IV dose, oral therapy can be initiated 15 min after the last intravenous dose at 25 to 50 mg every 6 h for 48 h.
- Thereafter, patients should receive a maintenance dose of up to 100 mg twice daily. The target resting heart rate is 50 to 60 beats per minute unless a limiting side effect is reached.
- Monitoring during intravenous beta-blocker therapy should include:
- Frequent checks of heart rate and blood pressure
- Continuous ECG monitoring
- Auscultation for rales and bronchospasm It's essential to note that beta blockade also may be started orally, in smaller initial doses if appropriate, within the first 24 h, in cases in which a specific clinical indication for intravenous initiation is absent or the safety of aggressive early beta blockade is a concern, as stated in the 2013 ACCF/AHA guidelines 1.
From the FDA Drug Label
In patients who tolerate the full intravenous dose (15 mg), initiate metoprolol tartrate tablets, 50 mg every 6 hours, 15 minutes after the last intravenous dose and continued for 48 hours. Start patients who appear not to tolerate the full intravenous on metoprolol tartrate tablets either 25 mg or 50 mg every 6 hours (depending on the degree of intolerance) 15 minutes after the last intravenous dose or as soon as their clinical condition allows.
The conversion from intravenous (IV) to oral metoprolol is as follows:
- Patients who tolerate the full IV dose of 15 mg can be started on 50 mg orally every 6 hours.
- Patients who do not tolerate the full IV dose can be started on 25 mg or 50 mg orally every 6 hours, depending on the degree of intolerance. 2
From the Research
Metoprolol Oral to IV Conversion
- The provided studies do not directly address the conversion of metoprolol from oral to IV administration.
- However, studies 3 and 4 discuss the use of metoprolol in various clinical settings, including hypertension and coronary CT angiography.
- Study 3 mentions that metoprolol is generally well tolerated and its beta 1-selectivity may facilitate its administration to certain patients.
- Studies 4 and 5 compare the efficacy of esmolol and metoprolol in achieving target heart rates during coronary CT angiography, but do not provide information on oral to IV conversion of metoprolol.
Efficacy of Esmolol and Metoprolol
- Studies 4 and 5 demonstrate that both esmolol and metoprolol are effective in achieving target heart rates during coronary CT angiography.
- Esmolol is shown to have a faster onset and shorter duration of action compared to metoprolol, with less profound and shorter duration of reduction in systolic blood pressure 5.
- Study 6 compares the efficacy of esmolol and nicardipine in hypertensive acute ischemic stroke patients, but does not provide information on metoprolol oral to IV conversion.
Clinical Considerations
- When converting metoprolol from oral to IV administration, clinicians should consider the patient's individual needs and clinical status.
- The provided studies do not offer specific guidance on the conversion ratio or dosing regimen for metoprolol oral to IV administration.
- Clinicians should consult relevant clinical guidelines and pharmacological resources to inform their decision-making regarding metoprolol oral to IV conversion 3, 4, 5.