What are the parameters for holding Metoprolol (beta blocker)?

Metoprolol Hold Parameters

Hold metoprolol when heart rate is consistently below 50 bpm or systolic blood pressure is below 100 mmHg, and always hold for symptomatic bradycardia regardless of the specific heart rate number. 1, 2

Primary Hold Parameters

Heart Rate Thresholds

• Hold metoprolol if heart rate <50 bpm consistently 1, 2
• Delay administration by 12 hours if heart rate is 45-49 bpm 1
• Hold immediately if heart rate <45 bpm consistently 1
• For IV metoprolol infusions, hold if heart rate drops below 50 bpm 1

Blood Pressure Thresholds

• Hold metoprolol if systolic blood pressure <100 mmHg 1, 2
• This threshold applies to both oral and IV formulations 1, 3

Symptomatic Bradycardia (Most Critical)

• Hold for any symptomatic bradycardia (HR <50-60 bpm with symptoms) regardless of absolute heart rate 2
• Symptoms include: dizziness, lightheadedness, syncope, altered mental status, chest discomfort, or signs of hypoperfusion 2
• Symptomatic bradycardia is an absolute contraindication to continued beta-blocker therapy 2

Absolute Contraindications Requiring Immediate Hold

Cardiac Conditions

• Signs of heart failure, low output state, or decompensated heart failure 2, 3, 4
• Listen for rales (pulmonary congestion) - if present, hold metoprolol 2
• Second or third-degree heart block without a functioning pacemaker 2, 3
• PR interval >0.24 seconds 2
• Cardiogenic shock or increased risk factors (age >70, systolic BP <120 mmHg, sinus tachycardia >110 bpm) 2

Respiratory Conditions

• Active asthma or reactive airways disease 2, 3, 4
• Listen for bronchospasm during administration - if present, hold immediately 2

Special Clinical Situations Requiring Hold or Dose Reduction

Hemodynamic Instability

• Hold if systolic BP <100 mmHg with symptoms (oliguria, altered mental status, cool extremities) 2
• Hold if evidence of hypoperfusion is present 2

Alternative Causes of Tachycardia

• Search for and treat alternative causes before continuing metoprolol: 1
  • Sepsis or infection
  • Hypovolemia
  • Pulmonary embolism
  • Anemia
• If any of these are present, consider short-term down-titration or discontinuation 1

Perioperative Context

• In the POISE trial, clinically significant hypotension was associated with adjusted OR of death and stroke of 4.97, and bradycardia with OR of 2.13 1
• This emphasizes the critical importance of avoiding frank hypotension and bradycardia 1

Dose Reduction Strategy (Instead of Complete Hold)

When parameters are borderline or patient has compelling indications (post-MI, heart failure):

• Reduce dose by 50% if: 2
  • Heart rate 50-55 bpm without symptoms
  • Systolic BP 100-110 mmHg without symptoms
• This maintains some beta-blockade benefit while reducing risk 2
• Complete discontinuation increases mortality risk 2.7-fold compared to continuous use 2

Critical Warning About Abrupt Discontinuation

• Never abruptly discontinue metoprolol - this can cause: 2, 4
  • Severe exacerbation of angina
  • Myocardial infarction
  • Ventricular arrhythmias
  • 50% mortality rate in one study 2
• If discontinuation is necessary, taper by 25-50% every 1-2 weeks 2

Common Pitfalls to Avoid

• Do not hold metoprolol for asymptomatic bradycardia (HR 50-60 bpm) in stable patients - assess for symptoms first 2
• Do not assume tachycardia requires more metoprolol - rule out sepsis, hypovolemia, PE, anemia first 1
• Do not ignore concurrent hypotension - the combination of bradycardia and hypotension is particularly dangerous 1, 2
• Do not restart at full dose after holding - restart at lowest dose (12.5 mg once daily) and titrate slowly 2