What are the order parameters for metoprolol (beta blocker) therapy?

Metoprolol Order Parameters

Formulation Selection

For heart failure with reduced ejection fraction (HFrEF), only metoprolol succinate extended-release (CR/XL) should be ordered, as this is the sole formulation proven to reduce mortality—metoprolol tartrate (immediate-release) has not demonstrated this benefit and should not be used for heart failure. 1, 2

• Metoprolol tartrate requires twice-daily dosing due to its 3-4 hour half-life and is appropriate for hypertension or acute coronary syndromes 3
• Metoprolol succinate extended-release allows once-daily dosing and is the evidence-based choice for HFrEF 1, 2

Indication-Specific Dosing Parameters

Heart Failure with Reduced Ejection Fraction

Starting dose: 12.5-25 mg once daily of metoprolol succinate ER, depending on heart failure severity 1, 2

Target dose: 200 mg once daily 1, 2

Titration schedule: Double the dose every 2 weeks if tolerated (12.5 mg → 25 mg → 50 mg → 100 mg → 200 mg) 1, 2

• Aim for at least 50% of target dose (100 mg daily minimum) if full target cannot be achieved, as dose-response relationships exist for mortality benefit 1, 2
• In the MERIT-HF trial, 64% of patients achieved the target dose of 200 mg daily, with a mean dose of 159 mg daily 1, 2
• This regimen achieved a 34% reduction in all-cause mortality, 38% decrease in cardiovascular mortality, and 35% reduction in heart failure hospitalizations 1

Hypertension

Metoprolol tartrate: 100-200 mg daily in divided doses (twice daily) 4

Metoprolol succinate: 50-200 mg once daily 4, 2

• Beta-blockers are not first-line agents for hypertension unless the patient has ischemic heart disease or heart failure 4, 1
• Cardioselective agents like metoprolol are preferred in patients with bronchospastic airway disease requiring a beta-blocker 4, 1

Post-Myocardial Infarction

Early treatment (IV to oral transition):

• IV: 5 mg bolus over 2 minutes, repeated every 5 minutes for total of 15 mg 3
• Oral: Begin 50 mg every 6 hours, 15 minutes after last IV dose, continued for 48 hours 3
• Maintenance: 100 mg twice daily thereafter 3

Long-term post-MI: Follow heart failure dosing regimen with metoprolol succinate 12.5-200 mg once daily 1

Contraindications to Check Before Ordering

Absolute contraindications: 3

• Signs of heart failure or low output state
• Systolic BP <120 mmHg with risk factors for cardiogenic shock
• Heart rate >110 bpm or <60 bpm
• PR interval >0.24 seconds
• Second or third-degree heart block without pacemaker
• Active asthma or reactive airways disease
• Cardiogenic shock

Relative contraindications requiring caution: 3

• First-degree AV block
• Sinus node dysfunction
• Age >70 years (especially for IV administration)
• Hepatic impairment (requires dose reduction and gradual titration)

Monitoring Parameters

During Initiation and Titration

At each visit: 1

• Heart rate (target 50-60 bpm for most indications)
• Blood pressure (hold if systolic <100 mmHg with symptoms)
• Clinical status for signs of congestion
• Body weight (daily weights recommended; increase diuretic if weight increases by 1.5-2.0 kg over 2 days)

At 12 weeks after initiation and 12 weeks after final dose titration: 1

• Blood chemistry (renal function, electrolytes)

Specific Monitoring Thresholds

For symptomatic bradycardia (HR <50 bpm with worsening symptoms): Halve the dose 1

For worsening congestion: First double diuretic dose; only halve metoprolol dose if increasing diuretic fails 1

For symptomatic hypotension: First reduce or eliminate vasodilators and diuretics (if no congestion) before reducing beta-blocker dose 1

Critical Prescribing Pitfalls to Avoid

Never order abrupt discontinuation of metoprolol, as this can precipitate severe exacerbation of angina, myocardial infarction, and ventricular arrhythmias—taper over 1-2 weeks when discontinuation is necessary 3

Do not substitute formulations: Metoprolol tartrate 50 mg twice daily is commonly prescribed but was neither the dose nor formulation used in trials showing mortality reduction in heart failure 2

Avoid IV metoprolol in high-risk acute MI patients: Early IV administration increased cardiogenic shock by 11 per 1000 patients, particularly in those >70 years, SBP <120 mmHg, HR >110 bpm, or Killip class >1 5

Do not underdose: Many clinicians maintain patients on suboptimal doses due to fear of side effects—some beta-blocker is better than no beta-blocker, but aim for evidence-based target doses 1

Special Population Considerations

Hepatic impairment: Initiate at low doses with cautious gradual titration, as elimination half-life may be prolonged up to 7.2 hours 3

Renal impairment: No dose adjustment required 3

Geriatric patients: Use low initial starting dose given greater frequency of decreased hepatic, renal, or cardiac function 3

Women: Consider 50% dose reduction on average, as metoprolol exposure is 50-80% higher in women than men, with similar efficacy at lower doses 5