What is the treatment for beta blocker induced bradycardia?

Treatment of Beta Blocker Induced Bradycardia

For patients with beta blocker induced bradycardia causing symptoms or hemodynamic compromise, glucagon is the first-line treatment, followed by high-dose insulin therapy and supportive measures as needed. 1

Initial Assessment and Management

• Evaluate for symptoms (dizziness, lightheadedness, syncope) and hemodynamic compromise (hypotension, shock) 1
• Discontinue the beta blocker if possible 1
• Monitor vital signs continuously, including heart rate, blood pressure, and oxygen saturation 1
• Establish reliable IV access for medication administration 1

First-Line Therapy

• Glucagon: Recommended as first-line therapy for symptomatic beta blocker-induced bradycardia 1
  • Dosing: 3-10 mg IV bolus followed by infusion of 3-5 mg/hour 1
  • Mechanism: Activates hepatic adenyl cyclase that bypasses beta-receptor blockade 1
  • Common side effect: Nausea and vomiting (caution in patients with compromised airway protection) 1

Second-Line Therapy

• High-dose insulin therapy: Reasonable when bradycardia persists despite glucagon 1, 2
  • Dosing: IV bolus of 1 unit/kg followed by infusion of 0.5-1 units/kg/hour 1, 2
  • Concurrent dextrosa administration: 0.5 g/kg bolus followed by 0.5 g/kg/hour 2
  • Monitoring: Check glucose every 15 minutes initially, then regularly 2
  • Monitor potassium levels; insulin causes intracellular potassium shift 2
  • Target potassium levels: 2.5-2.8 mEq/L 2

Additional Supportive Measures

• Atropine: May be considered but often ineffective in pure beta blocker toxicity 1, 3

  • Dosing: 0.5-1 mg IV (may repeat every 3-5 minutes to maximum 3 mg) 1
  • Mechanism: Blocks parasympathetic effects but doesn't directly counteract beta blockade 3

• Vasopressors/Inotropes: For persistent hypotension 1

  • Epinephrine: 2-10 mcg/min IV or 0.1-0.5 mcg/kg/min IV 1
  • Dopamine: 5-20 mcg/kg/min IV 1
  • Dobutamine: May be considered for inotropic support 1

Special Considerations

• Calcium administration: While primarily indicated for calcium channel blocker toxicity, may be beneficial in combined beta blocker and calcium channel blocker toxicity 1, 4

  • Calcium chloride (10%): 1-2 g IV every 10-20 min or infusion of 0.2-0.4 mL/kg/h 1
  • Calcium gluconate (10%): 3-6 g IV every 10-20 min or infusion at 0.6-1.2 mL/kg/h 1

• Renal impairment: Can worsen beta blocker toxicity due to reduced clearance, creating a dangerous cycle of worsening bradycardia and hypotension 5

• Combined therapy with calcium channel blockers: Particularly dangerous synergy that may require more aggressive intervention 6, 4

Refractory Cases

• Temporary cardiac pacing: Consider when pharmacologic therapy fails to restore adequate heart rate 1
• ECMO: May be considered in severe cases unresponsive to medical management 7

Monitoring During Treatment

• Continuous cardiac monitoring for heart rate and rhythm 1
• Frequent blood pressure measurements 1
• Regular assessment of mental status and peripheral perfusion 1
• Glucose monitoring when using high-dose insulin therapy 2
• Potassium monitoring during insulin therapy 2

Pitfalls to Avoid

• Failure to recognize synergistic effects of beta blockers with other medications (especially calcium channel blockers) or conditions (hyperkalemia, renal failure) 5, 6
• Overreliance on atropine, which has limited efficacy in pure beta blocker toxicity 1
• Inadequate glucose monitoring during high-dose insulin therapy 2
• Delay in initiating specific therapies while waiting for standard resuscitation measures to work 8