What is the typical dosage and usage of metoprolol (beta-blocker) for conditions such as hypertension, angina, and heart failure?

Metoprolol Dosing and Usage Guidelines

Hypertension

For hypertension, initiate metoprolol tartrate at 25-50 mg twice daily or metoprolol succinate extended-release at 50-200 mg once daily, with a maximum dose of 200 mg daily for tartrate and 400 mg daily for succinate. 1

• Beta-blockers including metoprolol are not recommended as first-line agents for hypertension unless the patient has coexisting ischemic heart disease or heart failure 2
• Target blood pressure reduction should be at least 20/10 mmHg, ideally to 140/90 mmHg or lower 1
• Metoprolol lowers blood pressure as effectively as other major antihypertensive drug classes 3
• Dosage can be increased gradually every 1-2 weeks if blood pressure control is not achieved 1

Angina Pectoris

For stable angina, target doses are metoprolol CR 200 mg once daily, or immediate-release metoprolol 50-200 mg twice daily. 3

• Beta-blockers reduce oxygen demand by decreasing heart rate, contractility, and blood pressure 3
• Metoprolol prolongs exercise tolerance and reduces anginal symptoms more effectively than calcium channel blockers like nifedipine 3
• The drug increases exercise tolerance and decreases symptom frequency and short-acting nitrate consumption 3
• Beta-1 selective agents like metoprolol are preferred due to fewer side effects compared with non-selective beta-blockers 3

Heart Failure with Reduced Ejection Fraction (HFrEF)

For heart failure, initiate metoprolol succinate extended-release at 12.5-25 mg once daily and titrate every 2 weeks to a target dose of 200 mg once daily. 1, 2

• Only metoprolol succinate (CR/XL), not metoprolol tartrate, has proven mortality reduction in heart failure 3
• The MERIT-HF trial demonstrated a 34% reduction in all-cause mortality, 38% decrease in cardiovascular mortality, 41% decrease in sudden death, and 49% decrease in death from progressive heart failure 3
• Titration schedule: 12.5 mg → 25 mg → 50 mg → 100 mg → 200 mg once daily, doubling the dose every 2 weeks as tolerated 2
• At the conclusion of MERIT-HF, 64% of patients achieved the target dose of 200 mg daily 2
• The number needed to treat is 27 patients for 1 year to prevent 1 death 2
• Even if target doses cannot be achieved, aim for at least 50% of target dose (100 mg daily minimum) as dose-response relationships exist for mortality benefit 2

Monitoring During Heart Failure Titration

• Monitor heart rate, blood pressure, clinical status, and signs of congestion 2
• Check blood chemistry 1-2 weeks after initiation and 1-2 weeks after final dose titration 2
• Patients should weigh themselves daily and increase diuretic dose if weight increases by 1.5-2.0 kg over 2 days 2
• For worsening congestion, double the diuretic dose first; only halve the beta-blocker dose if increasing diuretic fails 2
• For marked fatigue or bradycardia <50 bpm with worsening symptoms, halve the beta-blocker dose 2

Post-Myocardial Infarction

For early post-MI treatment, administer three 5 mg IV boluses at 2-minute intervals (total 15 mg), followed by oral metoprolol tartrate 50 mg every 6 hours starting 15 minutes after the last IV dose, continued for 48 hours, then transition to 100 mg twice daily for maintenance. 1, 4

• Treatment should be initiated as soon as possible after hospital arrival once hemodynamic stability is confirmed 4
• Monitor blood pressure, heart rate, and ECG during IV administration 4
• Patients who do not tolerate the full IV dose should start oral therapy at 25-50 mg every 6 hours depending on degree of intolerance 4
• The median delay from symptom onset to therapy initiation was 8 hours in clinical trials, with comparable mortality reductions for early and late treatment 4

Contraindications for Early IV Beta-Blocker Use

• Signs of heart failure, low output state, or increased risk for cardiogenic shock 1
• PR interval >0.24 seconds, second or third-degree heart block 1
• Active asthma or reactive airways disease 1
• Systolic BP <120 mmHg, heart rate >110 bpm or <60 bpm 1
• Age >70 years increases cardiogenic shock risk 1

Atrial Fibrillation Rate Control

For atrial fibrillation, administer 5 mg IV over 1-2 minutes, repeated every 5 minutes as needed to a maximum total dose of 15 mg, then transition to oral therapy at 25-50 mg every 6 hours for 48 hours. 1

• Target resting heart rate of 50-60 beats per minute unless limiting side effects occur 1
• For chronic rate control, use metoprolol tartrate 25-100 mg twice daily or metoprolol succinate 50-400 mg once daily 2
• Perform frequent checks of heart rate and blood pressure during IV therapy, with continuous ECG monitoring 1

Special Populations and Precautions

Hepatic Impairment

• Metoprolol blood levels increase substantially in hepatic impairment 4
• Initiate at low doses with cautious gradual titration according to clinical response 4
• Elimination half-life is considerably prolonged (up to 7.2 hours) depending on severity 4

Renal Impairment

• No dose adjustment required in patients with renal impairment 4
• Systemic availability and half-life do not differ clinically from normal subjects 4

Geriatric Patients

• Use a low initial starting dose given greater frequency of decreased hepatic, renal, or cardiac function 4
• Plasma concentrations may be slightly higher due to decreased metabolism and hepatic blood flow, though not clinically significant 4

CYP2D6 Poor Metabolizers

• Poor metabolizers (8% of Caucasians, 2% of other populations) exhibit several-fold higher plasma concentrations 4
• This decreases metoprolol's cardioselectivity and may require dose reduction 4
• Half-life may be 7-9 hours in poor metabolizers versus 3-4 hours in extensive metabolizers 4

Common Pitfalls and Caveats

• Never use metoprolol tartrate for heart failure—only metoprolol succinate has mortality benefit 3
• Avoid abrupt cessation of therapy to prevent rebound hypertension or worsening angina 1
• Do not administer IV metoprolol in patients with decompensated heart failure 1
• Cardioselectivity is lost at higher doses, increasing risk of bronchospasm 3
• Underdosing is common; many clinicians maintain patients on suboptimal doses due to fear of side effects 2
• Temporary fatigue, dizziness, and headache are among the most frequently reported side effects but often resolve with continued therapy 5