What is the effect of metoprolol (beta blocker) on blood pressure?

From the Guidelines

Metoprolol reduces blood pressure by approximately 10-15% in hypertensive patients, with the effect beginning within 1-2 hours of taking oral metoprolol and peak effects occurring in 6-8 hours. This beta-blocker works by blocking beta-1 receptors in the heart, reducing heart rate and cardiac output, which directly lowers blood pressure 1. The usual starting dose is 25-100 mg daily, often divided into two doses, with maintenance doses ranging from 100-400 mg daily depending on patient response. Blood pressure reduction is dose-dependent, with higher doses generally producing greater reductions.

Key Points to Consider

• The extended-release formulation (Toprol XL) can be taken once daily, improving convenience and compliance.
• Patients should monitor their blood pressure regularly when starting metoprolol, as individual responses vary.
• Side effects may include fatigue, dizziness, and bradycardia.
• Metoprolol should not be stopped abruptly as this can cause rebound hypertension; dosage should be gradually reduced over 1-2 weeks when discontinuing.
• Women may require lower doses due to increased exposure and higher oral bioavailability of metoprolol compared to men, as shown in a study published in Pharmacology and Therapeutics 1.

Dosage and Administration

• 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.
• Oral therapy can be initiated 15 min after the last intravenous dose at 25 to 50 mg every 6 h for 48 h, with a maintenance dose of up to 100 mg twice daily 1.

From the FDA Drug Label

Clinical pharmacology studies have demonstrated the beta-blocking activity of metoprolol, as shown by (1) reduction in heart rate and cardiac output at rest and upon exercise, (2) reduction of systolic blood pressure upon exercise, In several studies of patients with acute myocardial infarction, intravenous followed by oral administration of metoprolol caused a reduction in heart rate, systolic blood pressure and cardiac output

Metoprolol's effect on blood pressure is a reduction in systolic blood pressure, particularly upon exercise, as demonstrated in clinical pharmacology studies 2 2.

• The exact magnitude of the reduction is not specified in the provided drug labels.
• The reduction in blood pressure is associated with a decrease in cardiac output and heart rate.
• Diastolic blood pressure remains unchanged in patients with acute myocardial infarction.

From the Research

Effect of Metoprolol on Blood Pressure

• Metoprolol is a beta1-selective adrenoceptor blocking drug that has been shown to be effective in lowering blood pressure in patients with hypertension 3, 4, 5, 6.
• The drug has been found to reduce systolic blood pressure by 10-20 mmHg and diastolic blood pressure by 5-10 mmHg in patients with mild to moderate hypertension 5, 6.
• The effect of metoprolol on blood pressure is dose-dependent, with higher doses resulting in greater reductions in blood pressure 5.
• Metoprolol has been shown to be as effective as other beta-blockers, diuretics, and calcium channel blockers in lowering blood pressure in patients with hypertension 3, 4, 6.
• The addition of metoprolol to other antihypertensive therapies, such as ACE inhibitors or angiotensin receptor blockers, has been found to result in greater reductions in blood pressure than monotherapy with these agents 6.

Mechanism of Action

• Metoprolol works by selectively blocking beta1-adrenergic receptors in the heart, resulting in a decrease in heart rate and contractility, and a subsequent reduction in blood pressure 3, 4.
• The drug has also been found to have a positive effect on heart rate variability, which is an indicator of autonomic function, in patients with diabetes and abnormal albuminuria 7.

Clinical Implications

• Metoprolol is a commonly used medication for the treatment of hypertension, angina pectoris, and heart failure 3, 4.
• The drug is generally well-tolerated, with common side effects including fatigue, dizziness, and headache 3, 4.
• Metoprolol may be particularly useful in patients with certain comorbidities, such as diabetes or asthma, due to its selective beta1-blocking activity 3, 4.