From the Guidelines
To convert oral metoprolol 100 mg daily to intravenous dosing, administer 2.5-5 mg IV every 2 minutes, up to 3 doses, as needed, based on the most recent guidelines from 2024 1. This recommendation is based on the latest evidence from the 2023 ACC/AHA/ACCp/HRS guideline for the diagnosis and management of atrial fibrillation, which provides the most up-to-date information on the use of metoprolol for rate control in patients with atrial fibrillation. When switching from oral to IV metoprolol, it's essential to monitor the patient's blood pressure and heart rate closely, as the IV route provides 100% bioavailability compared to the 50% bioavailability of oral metoprolol. The onset of action is also faster with IV administration. If the patient is hemodynamically unstable, consider starting with a lower dose of 2.5 mg IV and titrating up as needed. The IV formulation should be given as a slow push over 1-2 minutes to avoid precipitous drops in blood pressure. Some key points to consider when using metoprolol for rate control include:
- Monitoring for signs of heart block, bronchospasm, or hypotension
- Adjusting the dose based on the patient's response and clinical status
- Considering alternative agents, such as calcium channel blockers or digoxin, if metoprolol is not effective or tolerated
- Being aware of potential interactions with other medications, such as warfarin or amiodarone. Overall, the use of IV metoprolol for rate control in patients with atrial fibrillation requires careful consideration of the patient's clinical status, close monitoring, and adjustment of the dose as needed to achieve optimal results.
From the FDA Drug Label
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. 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. Thereafter, the maintenance dosage is 100 mg orally twice daily
The IV equivalent of 100mg daily metoprolol (Metoprolol) orally (PO) cannot be directly determined from the provided information, as the label does not provide a direct conversion from oral to IV dosing for the specified daily dose. 2
From the Research
IV Equivalent of Metoprolol
To determine the IV equivalent of 100mg daily metoprolol orally, we need to examine the pharmacokinetic properties of metoprolol and its various formulations.
- The study 3 discusses the controlled release/extended-release formulation of metoprolol succinate, which provides relatively constant metoprolol plasma concentrations and beta(1)-blockade.
- However, none of the provided studies directly address the IV equivalent of 100mg daily metoprolol orally.
- Study 4 mentions that metoprolol 15 mg i.v. in three divided doses was administered to patients, but it does not provide a direct comparison to the oral dose.
- Study 5 discusses the use of intravenous metoprolol after a suboptimal heart rate response to oral metoprolol, but it does not provide a specific equivalent dose.
- Studies 6 and 7 focus on the effects of metoprolol in chronic heart failure and suppressing exercise-induced and daily myocardial ischemia, respectively, but do not address the IV equivalent of the oral dose.
Available Information
- The available information does not provide a direct equivalent of 100mg daily metoprolol orally to an IV dose.
- Further research or consultation of additional studies may be necessary to determine the IV equivalent of metoprolol.