From the Guidelines
Extended release metoprolol (metoprolol succinate) is a beta-blocker medication that should be used to reduce morbidity and mortality in patients with heart failure, unless contraindicated, as recommended by the 2020 ACC/AHA clinical performance and quality measures for adults with heart failure 1. The medication comes in a formulation designed to release the drug slowly over time, providing a consistent therapeutic effect for 24 hours with once-daily dosing. It's primarily used to treat high blood pressure, angina (chest pain), and heart failure, and can help reduce the risk of death after a heart attack. The extended release formulation offers advantages over immediate release metoprolol tartrate, including better compliance with once-daily dosing, more stable blood levels throughout the day, and potentially fewer side effects due to avoiding peak concentrations. Some key points to consider when using extended release metoprolol include:
- Common dosages range from 25mg to 200mg once daily, with the dose typically adjusted based on patient response, as seen in the POISE trial where patients received extended-release metoprolol 100 mg or placebo starting 2 to 4 hours before surgery and continued for 30 days 1.
- Side effects may include fatigue, dizziness, slow heart rate, and cold extremities.
- The medication works by blocking beta-1 adrenergic receptors in the heart, reducing heart rate and the force of heart contractions, which lowers blood pressure and decreases the heart's workload and oxygen demand.
- Initiation of beta-blocker therapy is recommended after optimization of volume status and successful discontinuation of intravenous diuretics, vasodilators, and inotropic agents, and should be initiated at a low dose and only in stable patients, as recommended by the 2020 ACC/AHA clinical performance and quality measures for adults with heart failure 1.
- The use of extended release metoprolol is supported by the 2013 ACCF/AHA guideline for the management of heart failure, which recommends the use of one of the three beta blockers proven to reduce mortality, including sustained-release metoprolol succinate, for all patients with current or prior symptoms of HFrEF, unless contraindicated, to reduce morbidity and mortality 1.
From the FDA Drug Label
CLINICAL PHARMACOLOGY Mechanism of Action Metoprolol is a beta 1-selective (cardioselective) adrenergic receptor blocker. The FDA drug label does not answer the question.
From the Research
Definition and Mechanism of Extended Release Metoprolol
- Extended release metoprolol, also known as metoprolol succinate, is a beta(1)-selective beta-blocker used in the treatment of hypertension, angina pectoris, and heart failure 2, 3.
- It works by reducing the heart rate and the force of contraction, thereby decreasing the oxygen demand of the heart and reducing blood pressure.
Clinical Uses of Extended Release Metoprolol
- Extended release metoprolol is used in the treatment of severe heart failure, where it has been shown to reduce mortality and hospitalizations due to worsening heart failure 2.
- It is also used in the treatment of hypertension, where it has been shown to be effective in reducing blood pressure and preventing cardiovascular events 3, 4.
- In addition, extended release metoprolol is used in the treatment of angina pectoris, where it helps to reduce the frequency and severity of angina attacks 3.
Comparison with Other Beta-Blockers
- Extended release metoprolol has been compared with other beta-blockers, such as atenolol, bisoprolol, and carvedilol, in terms of its effectiveness in reducing mortality and cardiovascular events 5, 6.
- Studies have shown that extended release metoprolol may have a more favorable effect on mortality and cardiovascular events compared to atenolol, but may not be as effective as carvedilol in reducing all-cause mortality in patients with heart failure 5, 6.
Pharmacokinetics and Pharmacodynamics
- Extended release metoprolol is formulated to release the active ingredient slowly over a period of time, allowing for once-daily dosing 2.
- It has a beta(1)-selective mechanism of action, which means that it primarily affects the heart rate and contractility, with minimal effects on airway smooth muscle and peripheral blood vessels 2, 3.