What are the typical dosages of metoprolol (beta-blocker) for various conditions?

Metoprolol Dosage Guidelines for Various Conditions

The typical dosage of metoprolol varies by formulation (tartrate vs. succinate) and indication, with hypertension requiring 25-100 mg twice daily for tartrate or 50-200 mg once daily for succinate, while heart failure requires careful titration starting at 12.5-25 mg with a target of 200 mg daily. 1, 2, 3

Hypertension Dosing

• For hypertension, metoprolol tartrate is typically started at 25-50 mg twice daily, with titration up to a maximum of 100 mg twice daily (200 mg total daily dose) 1, 2
• Metoprolol succinate (extended-release) is dosed at 50-200 mg once daily for hypertension, with a maximum dose of 400 mg daily 2
• In elderly hypertensive patients (≥65 years), a lower starting dose is recommended due to potential decreased hepatic, renal, or cardiac function, with 100 mg daily often being better tolerated than higher doses 4, 5
• Dosage can be increased gradually every 1-2 weeks if blood pressure control is not achieved 2

Heart Failure Dosing

• For heart failure with reduced ejection fraction (HFrEF), metoprolol succinate is the preferred formulation with an initial dose of 12.5-25 mg once daily 1, 2
• Careful uptitration is essential, with increases no more frequently than every 2 weeks, targeting 200 mg once daily or maximally tolerated dose 1, 6
• The target dose of metoprolol succinate for heart failure is 200 mg once daily, as demonstrated in the MERIT-HF trial 1, 6
• At minimum, achieving at least 50% of the target dose (100 mg daily) is recommended for mortality benefit in heart failure 1

Angina Pectoris Dosing

• For angina pectoris, metoprolol tartrate is dosed at 50-100 mg twice daily, with a total daily dose ranging from 100-400 mg 1, 4
• Controlled-release metoprolol (200 mg once daily) may provide better 24-hour angina control compared to conventional tablets (100 mg twice daily) 7
• The antianginal efficacy is comparable between once-daily controlled-release formulation and twice-daily conventional tablets 7

Myocardial Infarction Dosing

• For acute myocardial infarction, initial treatment begins with three intravenous bolus injections of 5 mg metoprolol tartrate at approximately 2-minute intervals 4
• If the patient tolerates the full IV dose (15 mg), transition to oral metoprolol tartrate 50 mg every 6 hours for 48 hours, followed by maintenance dose of 100 mg twice daily 4
• For patients with intolerance to the full IV dose, start with 25-50 mg oral metoprolol tartrate every 6 hours based on the degree of intolerance 4

Intravenous Dosing

• For supraventricular tachycardia, IV metoprolol is administered as 5 mg over 1-2 minutes, repeated as required every 5 minutes to a maximum dose of 15 mg 2, 1
• In acute settings like hypertensive emergencies with cardiac ischemia, IV metoprolol can be given as 2.5-5 mg bolus over 2 minutes, repeated every 5 minutes to a maximum of 15 mg 1

Special Populations

• In patients with hepatic impairment, metoprolol blood levels may increase substantially, requiring lower initial doses with cautious gradual titration 4
• No dose adjustment is required for patients with renal impairment 4
• For elderly patients, use lower initial doses due to potential changes in drug metabolism and increased risk of adverse effects 2, 4

Common Pitfalls and Caveats

• Avoid abrupt discontinuation of metoprolol as it may lead to rebound hypertension or worsening angina; taper by reducing dose by 25-50% every 1-2 weeks 2
• Metoprolol is contraindicated in patients with signs of heart failure decompensation, cardiogenic shock, PR interval >0.24 seconds, second or third-degree heart block, and active asthma or reactive airways disease 2, 3
• Beta-blockers are not recommended as first-line agents for hypertension unless the patient has ischemic heart disease or heart failure 1
• Metoprolol tartrate loses its beta-1 selectivity at higher doses, which may increase risk of bronchospasm in susceptible patients 8
• Metoprolol metabolism is affected by CYP2D6 genetic polymorphism; poor metabolizers (8% of Caucasians) may have several-fold higher plasma concentrations and longer half-life (7-9 hours vs. 3-4 hours) 4