What is the typical dosing regimen for metoprolol (beta-blocker) in treating hypertension and heart failure?

Metoprolol Dosing for Hypertension and Heart Failure

For hypertension, start metoprolol tartrate at 25-50 mg twice daily (maximum 200 mg/day) or metoprolol succinate extended-release at 50-200 mg once daily (maximum 400 mg/day); for heart failure with reduced ejection fraction, use only metoprolol succinate starting at 12.5-25 mg once daily and titrate every 2 weeks to a target of 200 mg once daily. 1, 2

Hypertension Dosing

Initial Dosing

• Metoprolol tartrate (immediate-release): Start at 25-50 mg orally twice daily 1, 2
• Metoprolol succinate (extended-release): Start at 50 mg once daily 1
• Beta-blockers are not first-line agents for hypertension unless the patient has coexisting ischemic heart disease or heart failure 3, 2

Titration Schedule

• Increase dosage gradually every 1-2 weeks if blood pressure control is inadequate 1, 2
• Maximum dose for tartrate: 100 mg twice daily (200 mg total daily) 1, 2
• Maximum dose for succinate: 400 mg once daily 1, 2
• Target blood pressure reduction should be at least 20/10 mmHg, ideally to <140/90 mmHg 1

Monitoring Parameters

• Check blood pressure and heart rate at each visit 1
• Target resting heart rate of 50-60 beats per minute unless limiting side effects occur 1

Heart Failure with Reduced Ejection Fraction (HFrEF) Dosing

Critical Formulation Distinction

Only metoprolol succinate extended-release (CR/XL) has proven mortality reduction in heart failure—metoprolol tartrate does NOT have this evidence. 2, 4

Initial Dosing

• Start at 12.5-25 mg once daily of metoprolol succinate, depending on heart failure severity 1, 3, 2
• For very cautious initiation in severe cases, 12.5 mg once daily is appropriate 1

Titration Protocol

• Double the dose every 2 weeks as tolerated 3, 2
• Standard progression: 12.5 mg → 25 mg → 50 mg → 100 mg → 200 mg once daily 1, 2
• Do not increase more frequently than every 2 weeks 2

Target Dosing

• Target dose: 200 mg once daily 1, 3, 2
• This target achieved a 34% reduction in all-cause mortality in the MERIT-HF trial 1, 2, 4
• Minimum effective dose: Aim for at least 50% of target (100 mg daily minimum) if full target cannot be achieved, as dose-response relationships exist for mortality benefit 2
• Even lower doses provide benefit if target doses cannot be tolerated 3

Clinical Benefits at Target Dose

• 34% decrease in all-cause mortality 1, 4
• 38% decrease in cardiovascular mortality 1
• 41% decrease in sudden death 1
• 49% decrease in death from progressive heart failure 1
• 35% reduction in hospitalization due to heart failure 1
• Number needed to treat: 27 patients for 1 year to prevent 1 death 3

Monitoring During Titration

• Monitor for signs of worsening heart failure (increased dyspnea, weight gain, peripheral edema) 2
• Daily weights recommended—increase diuretic if weight increases by 1.5-2.0 kg over 2 days 3, 2
• Check blood chemistry 12 weeks after initiation and 12 weeks after final dose titration 3
• Monitor heart rate, blood pressure, and clinical status at each visit 3

Managing Adverse Effects During Titration

• For worsening congestion: Double diuretic dose first; only halve beta-blocker dose if increasing diuretic fails 3, 2
• For marked fatigue or bradycardia <50 bpm with worsening symptoms: Halve the beta-blocker dose 3, 2
• For symptomatic hypotension: First reduce or eliminate vasodilators (nitrates, calcium channel blockers), then consider reducing diuretics if no congestion present, and only reduce metoprolol as last resort 3

Acute Myocardial Infarction Dosing

Early IV Treatment

• Administer three 5 mg IV boluses over 1-2 minutes each, at approximately 2-minute intervals (total 15 mg) 1, 5
• Monitor blood pressure, heart rate, and ECG continuously during IV administration 5
• This must be done in a coronary care or similar unit with intensive monitoring 5

Transition to Oral Therapy

• In patients tolerating full IV dose: Start metoprolol tartrate 50 mg orally every 6 hours, beginning 15 minutes after last IV dose, and continue for 48 hours 1, 5
• After 48 hours: Transition to maintenance dose of 100 mg orally twice daily 1, 5
• In patients with intolerance to full IV dose: Start 25-50 mg every 6 hours (depending on degree of intolerance) 15 minutes after last IV dose 5

Absolute Contraindications

Do not administer metoprolol if any of the following are present: 1, 2

• Signs of heart failure decompensation or low output state
• Increased risk for cardiogenic shock (age >70 years, systolic BP <120 mmHg, heart rate >110 or <60 bpm) 1
• PR interval >0.24 seconds
• Second or third-degree heart block without functioning pacemaker
• Active asthma or reactive airways disease
• Cardiogenic shock
• Severe bradycardia (<45 bpm) 1

Critical Warnings

Never Abruptly Discontinue

• Abrupt cessation can cause severe exacerbation of angina, myocardial infarction, and ventricular arrhythmias with 50% mortality rate in one study 1
• Taper by reducing dose by 25-50% every 1-2 weeks 1, 2
• Beta-blocker withdrawal is associated with 2.7-fold increased risk of 1-year mortality 1

Special Populations

• Elderly patients: Start at low doses with cautious gradual titration due to decreased hepatic function 5
• Hepatic impairment: Initiate at low doses with cautious gradual titration; elimination half-life considerably prolonged (up to 7.2 hours) 5
• Renal impairment: No dose adjustment required 5

Common Pitfalls to Avoid

• Using metoprolol tartrate instead of succinate for heart failure—only succinate has mortality benefit 2, 4
• Stopping beta-blocker first when managing hypotension—adjust vasodilators and diuretics first 3
• Underdosing in heart failure due to fear of side effects—aim for at least 50% of target dose 3, 2
• Administering IV metoprolol in decompensated heart failure or high-risk acute MI patients 1
• Titrating faster than every 2 weeks in heart failure 3, 2