What is the recommended dose and frequency of metoprolol (beta blocker) for various clinical indications, including hypertension, angina, heart failure, and acute myocardial infarction?

From the Guidelines

Metoprolol dosing varies by indication and formulation, with specific recommendations for hypertension, angina, heart failure, and acute myocardial infarction, as outlined in the guidelines from the American College of Cardiology and American Heart Association 1.

Indications and Dosing

• For hypertension, start with 25-100 mg twice daily of immediate-release (IR) or 50-100 mg once daily of extended-release (ER), titrating up to 400 mg daily if needed 1.
• For angina, begin with 25-50 mg IR twice daily or 100 mg ER once daily, increasing as needed to 200-400 mg daily 1.
• In heart failure, start low at 12.5-25 mg ER once daily, doubling the dose every two weeks as tolerated to a target of 200 mg daily 1.
• For acute myocardial infarction, give 5 mg IV bolus every 2 minutes for three doses, followed by 25-50 mg orally every 6 hours for 48 hours, then transition to maintenance therapy of 100 mg twice daily 1.

Important Considerations

• Metoprolol should be taken with food to enhance absorption and reduce side effects.
• Dose adjustments are necessary for patients with hepatic impairment, as metoprolol is primarily metabolized by the liver.
• The medication works by blocking beta-1 adrenergic receptors, reducing heart rate, contractility, and blood pressure, which decreases myocardial oxygen demand and improves symptoms across these cardiovascular conditions.

Key Points

• The choice of beta blocker for an individual patient is based primarily on pharmacokinetic and side effect criteria, as well as on physician familiarity 1.
• Beta blockers are recommended for the long-term management of patients with hypertension-related left ventricular systolic dysfunction, with metoprolol being one of the preferred agents 1.

From the FDA Drug Label

In controlled clinical studies, metoprolol has been shown to be an effective antihypertensive agent when used alone or as concomitant therapy with thiazide-type diuretics, at oral dosages of 100 to 450 mg daily In controlled clinical trials, metoprolol, administered orally two or four times daily, has been shown to be an effective antianginal agent, reducing the number of angina attacks and increasing exercise tolerance. The oral dosage used in these studies ranged from 100 to 400 mg daily Initial treatment consisted of intravenous followed by oral administration of metoprolol or placebo, given in a coronary care or comparable unit. Oral maintenance therapy with metoprolol or placebo was then continued for 3 months.

The recommended dose and frequency of metoprolol for various clinical indications are:

• Hypertension: 100 to 450 mg daily
• Angina: 100 to 400 mg daily, administered orally two or four times daily
• Myocardial Infarction: The study used intravenous followed by oral administration, with oral maintenance therapy continued for 3 months, but the exact dosage is not specified in the label. It is reasonable to administer the drug orally to patients at a later time as is recommended for certain other beta-blockers 2.

From the Research

Dose and Frequency of Metoprolol

The recommended dose and frequency of metoprolol vary depending on the clinical indication.

• For hypertension, the typical starting dose is 100 mg daily, which can be increased to 200 mg daily if needed 3.
• For angina, the typical dose is 100-200 mg daily 3.
• For heart failure, the typical starting dose is 25 mg twice daily, which can be increased to 200 mg daily if needed 4.
• For acute myocardial infarction, the typical dose is 200 mg daily 5.

Clinical Indications

The following are some clinical indications for metoprolol:

• Hypertension: metoprolol is effective in reducing blood pressure and is often used as a first-line treatment 3.
• Angina: metoprolol is effective in reducing the frequency and severity of angina attacks 3.
• Heart failure: metoprolol is effective in reducing mortality and morbidity in patients with heart failure 4.
• Acute myocardial infarction: metoprolol is effective in reducing mortality and morbidity in patients with acute myocardial infarction 5, 6.

Pharmacokinetics

The pharmacokinetics of metoprolol vary depending on the formulation and route of administration.

• The oral bioavailability of metoprolol is approximately 50% 7.
• The peak plasma concentration of metoprolol is reached within 1-2 hours after oral administration 7.
• The half-life of metoprolol is approximately 3-4 hours 7.

Special Considerations

The following are some special considerations for metoprolol:

• Renal impairment: metoprolol should be used with caution in patients with renal impairment, as it can increase the risk of adverse effects 7.
• Hepatic impairment: metoprolol should be used with caution in patients with hepatic impairment, as it can increase the risk of adverse effects 7.
• Drug interactions: metoprolol can interact with other medications, such as beta-blockers and calcium channel blockers, which can increase the risk of adverse effects 7.