When should metoprolol (beta blocker) be held in hospital patients?

When to Hold Metoprolol in Hospitalized Patients

Metoprolol should be held in hospitalized patients who have signs of heart failure, evidence of a low output state, increased risk for cardiogenic shock, or other contraindications to beta blockade including PR interval >0.24 seconds, second/third-degree heart block, active asthma, or reactive airway disease. 1

Specific Clinical Scenarios Requiring Metoprolol Discontinuation

Hemodynamic Concerns

• Heart failure: Signs of worsening heart failure or cardiogenic shock 1, 2
• Hypotension: Systolic blood pressure <100 mmHg 1
• Bradycardia: Heart rate <50 bpm 1
• Low cardiac output state: Clinical evidence of hypoperfusion 1, 2

Cardiac Conduction Abnormalities

• PR interval >0.24 seconds 1
• Second or third-degree heart block 1
• Sick sinus syndrome without permanent pacemaker 1

Respiratory Concerns

• Active asthma exacerbation 1, 2
• Acute bronchospasm or reactive airway disease 1, 2

Risk Factors for Cardiogenic Shock

• Age >70 years with other risk factors 1
• Systolic blood pressure <120 mmHg 1
• Sinus tachycardia >110 bpm or bradycardia <60 bpm 1
• Increased time since onset of symptoms in STEMI patients 1
• Killip class >1 in acute MI patients 1

Evidence-Based Considerations

The COMMIT/CCS-2 trial demonstrated that metoprolol administration in acute MI patients was associated with an average relative increase in cardiogenic shock of 30%, particularly in high-risk patients 1. This risk was most pronounced during days 0-1 after hospitalization.

In perioperative settings, the POISE trial showed that clinically significant hypotension with metoprolol was associated with an adjusted odds ratio for death and stroke of 4.97, while clinically significant bradycardia had an adjusted odds ratio of 2.13 1. This highlights the importance of careful hemodynamic monitoring when using metoprolol.

Monitoring Parameters

When administering metoprolol in hospitalized patients, monitor:

• Heart rate (hold if <50 bpm) 1
• Blood pressure (hold if systolic <100 mmHg) 1
• Signs and symptoms of heart failure 2
• ECG for conduction abnormalities 1

Common Pitfalls to Avoid

1. Abrupt discontinuation: Never abruptly stop metoprolol in patients with coronary artery disease as this can cause severe exacerbation of angina, MI, or ventricular arrhythmias 2

2. Missing alternative causes of tachycardia: When a patient on metoprolol has persistent tachycardia, investigate for alternative causes such as sepsis, hypovolemia, pulmonary embolism, or anemia before increasing the dose 1

3. Failure to recognize masked hypoglycemia: Beta-blockers may mask tachycardia associated with hypoglycemia in diabetic patients 2

4. Overlooking drug interactions: Metoprolol metabolism can be affected by other medications, potentially leading to higher plasma levels and increased risk of adverse effects

By carefully monitoring patients and following these guidelines for when to hold metoprolol, clinicians can maximize the benefits while minimizing the risks associated with beta-blocker therapy in hospitalized patients.