What are the recommended dosing regimens for metoprolol tartrate for hypertension, chronic stable angina, acute myocardial infarction, atrial fibrillation, and in elderly patients or those with hepatic impairment?

Metoprolol Tartrate Dosing Guidelines

Hypertension

For hypertension, initiate metoprolol tartrate at 25-50 mg twice daily and titrate every 1-2 weeks to a maximum of 200 mg daily (100 mg twice daily), targeting blood pressure <130/80 mmHg. 1

• Start with 25-50 mg orally twice daily 1
• Increase dose gradually every 1-2 weeks based on blood pressure response 1
• Maximum dose: 200 mg daily total (100 mg twice daily) 1
• Target blood pressure reduction: at least 20/10 mmHg, ideally to <130/80 mmHg 1
• Monitor blood pressure and heart rate at each visit during titration 1

Chronic Stable Angina

Begin metoprolol tartrate at 25-50 mg twice daily and titrate to 200 mg daily over 2-3 weeks, targeting a resting heart rate of 50-60 bpm unless limiting side effects occur. 1

• Initial dose: 25-50 mg twice daily 1
• Target dose: 200 mg daily (100 mg twice daily) 1
• Titrate gradually every 1-2 weeks as tolerated 1
• Target resting heart rate: 50-60 bpm 1
• Maximum dose: 200 mg twice daily (400 mg total daily) 1

Acute Myocardial Infarction

Administer metoprolol tartrate 25-50 mg orally every 6 hours starting 15 minutes after the last IV dose (if IV was given), then transition to 100 mg twice daily after 48 hours in hemodynamically stable patients without contraindications. 1

IV Administration (Acute Phase)

• Give 5 mg IV over 1-2 minutes 1
• Repeat every 5 minutes for up to 3 doses (maximum 15 mg total) 1
• Monitor heart rate, blood pressure, and ECG continuously 1

Absolute contraindications to IV metoprolol: 1

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

Oral Transition

• Start oral metoprolol tartrate 15 minutes after last IV dose 1
• Initial oral dose: 25-50 mg every 6 hours for 48 hours 1
• Maintenance: 100 mg twice daily 1
• Target for secondary prevention: transition to metoprolol succinate 200 mg once daily over 2-3 weeks 1

Critical warning: Early IV metoprolol increases cardiogenic shock risk by 11 per 1,000 patients, particularly in the first 24 hours, especially in high-risk patients (age >70, SBP <120 mmHg, HR >110 or <60 bpm, Killip class >1). 1

Atrial Fibrillation Rate Control

For atrial fibrillation, start metoprolol tartrate at 25-50 mg twice daily and titrate to 25-100 mg twice daily, targeting a resting heart rate of 50-80 bpm for strict control or <110 bpm for lenient control. 1

Oral Dosing

• Initial: 25-50 mg twice daily 1
• Maintenance: 25-100 mg twice daily 1
• Target resting heart rate: 50-80 bpm (strict control) or <110 bpm (lenient control) 1

IV Dosing (Acute Rate Control)

• 5 mg IV over 1-2 minutes 1
• Repeat every 5 minutes as needed (maximum 15 mg total) 1
• Transition to oral therapy 15 minutes after last IV dose 1

Contraindications specific to atrial fibrillation: 1

• Pre-excitation syndromes (WPW) - metoprolol may paradoxically accelerate ventricular response
• Decompensated heart failure
• Hemodynamic instability

Elderly Patients

In elderly patients, start metoprolol tartrate at the lowest dose (12.5-25 mg twice daily) and titrate more slowly (every 2-4 weeks) due to increased drug exposure and sensitivity. 1

• Initial dose: 12.5-25 mg twice daily 1
• Titrate every 2-4 weeks (slower than younger patients) 1
• Monitor closely for hypotension, bradycardia, and fatigue 1
• Elderly women require particularly cautious dosing: 15 mg in elderly women produces similar exposure to 50 mg in young men 1

Special consideration for women: Women achieve 50-80% higher metoprolol exposure than men at equivalent doses, with optimal heart failure outcomes at 50% of guideline-recommended doses. 1

Hepatic Impairment

For patients with hepatic impairment, initiate metoprolol tartrate at 12.5-25 mg twice daily and titrate cautiously, as hepatic metabolism is reduced and drug exposure is significantly increased. 1

• Start at lowest dose: 12.5-25 mg twice daily 1
• Titrate more slowly than in patients with normal hepatic function 1
• Monitor closely for signs of excessive beta-blockade (bradycardia, hypotension, fatigue) 1

Critical Monitoring Parameters Across All Indications

Monitor heart rate and blood pressure before each dose adjustment, watching specifically for symptomatic bradycardia (HR <60 bpm with dizziness), hypotension (SBP <100 mmHg with symptoms), and signs of worsening heart failure. 1

• Heart rate and blood pressure at each visit 1
• Signs of worsening heart failure (dyspnea, edema, weight gain) 1
• Symptomatic bradycardia (HR <60 bpm with dizziness, lightheadedness, syncope) 1
• Symptomatic hypotension (SBP <100 mmHg with dizziness, blurred vision) 1
• Bronchospasm, particularly in patients with any history of reactive airway disease 1

Common Pitfalls to Avoid

Never abruptly discontinue metoprolol, as sudden withdrawal causes a 2.7-fold increased risk of 1-year mortality, severe angina exacerbation, myocardial infarction, and ventricular arrhythmias. 1

• Taper by 25-50% every 1-2 weeks when discontinuing 1
• Do not give IV metoprolol to patients with decompensated heart failure - wait until clinical stabilization 1
• Do not administer the full 15 mg IV dose rapidly or as a single bolus - increases hypotension and bradycardia risk 1
• Do not assume all patients tolerate the same dose - women and elderly require lower doses 1