What are the guidelines for holding metoprolol (beta blocker) before a procedure to prevent hypotension?

Guidelines for Holding Metoprolol to Prevent Perioperative Hypotension

Metoprolol should be withheld if systolic blood pressure drops below 100 mmHg to prevent perioperative hypotension, stroke, and increased mortality risk. 1

Evidence-Based Parameters for Holding Metoprolol

• Withhold metoprolol if systolic blood pressure is below 100 mmHg, as this threshold was used in major trials and is associated with reduced hypotension-related complications 1
• Hypotension is a significant concern with perioperative metoprolol use, occurring in 15% of patients receiving the medication versus 9.7% in control groups (p<0.0001) 1
• Post-hoc analysis from the POISE trial showed that hypotension carried the greatest attributable risk for death and stroke in patients receiving perioperative beta-blockers 1

Timing Considerations

• The onset of action for oral metoprolol begins within 1-2 hours after administration, with significant hemodynamic effects observed within 2-4 hours of ingestion 2
• For patients on chronic metoprolol therapy, the medication should be continued perioperatively when indicated for established conditions (e.g., coronary artery disease, heart failure) 1
• When initiating metoprolol before surgery, it should ideally be started days to weeks before elective surgery with appropriate dose titration, rather than starting high doses on the day of surgery 1

Formulation-Specific Considerations

• Metoprolol tartrate has a shorter half-life (3-4 hours) and is typically dosed twice daily 3
• Metoprolol succinate (extended-release) has a longer duration of action and is dosed once daily 3
• The POISE trial used metoprolol succinate with a high initial dose (100 mg 2-4 hours before surgery), which may have contributed to the observed hypotension 1

Monitoring Parameters

• Regular monitoring of heart rate and blood pressure is essential when administering perioperative metoprolol 2, 3
• Target heart rate during beta-blocker therapy should be 60-80 bpm intraoperatively and postoperatively 1
• Patients with a history of cerebrovascular disease require particularly careful monitoring, as they showed an increased risk of stroke with perioperative beta-blockade in the POISE trial 1

High-Risk Scenarios Requiring Extra Caution

• Patients with severe heart failure, cardiogenic shock, marked first-degree AV block, or severe bronchospastic lung disease should not receive acute beta-blocker therapy 2
• Patients with hepatic impairment may experience prolonged half-life and potentially more pronounced side effects 2
• Elderly patients may be more susceptible to hypotension and should be monitored more closely 1

Practical Algorithm for Perioperative Metoprolol Management

1. For patients on chronic metoprolol therapy:

   • Continue the medication if indicated for established conditions 1
   • Withhold dose if systolic BP <100 mmHg 1
   • Monitor heart rate, aiming for 60-80 bpm 1

2. For patients being newly started on metoprolol:

   • Begin therapy days to weeks before surgery when possible 1
   • Start with low doses and gradually titrate 3
   • Avoid initiating high-dose metoprolol on the day of surgery 1
   • Withhold if systolic BP <100 mmHg 1

3. Intraoperative management:

   • Continue to monitor BP and heart rate 2
   • Be prepared to treat hypotension promptly if it occurs 1
   • Consider that metoprolol decreases the amount of anesthetic required to induce hypotension 4