What is the antidote for a beta blocker overdose?

Beta Blocker Overdose Antidote Management

High-dose insulin is the recommended first-line antidote for beta blocker overdose, followed by glucagon and vasopressors for refractory cases. 1

First-Line Therapies

High-Dose Insulin Therapy

• Strongest recommendation (Class 1, Level B-NR) for hypotension due to beta blocker poisoning 1
• Dosing protocol:
  • Initial bolus: 1 U/kg regular insulin IV
  • Maintenance: 0.5-1 U/kg/hour continuous infusion
  • Concurrent dextrose: 0.5 g/kg bolus followed by 0.5 g/kg/hour infusion
  • Titrate insulin to hemodynamic response
  • Titrate dextrose to maintain glucose 100-250 mg/dL 1
• Monitor glucose frequently (every 15 minutes initially)
• Monitor potassium levels; target moderate hypokalemia (2.5-2.8 mEq/L) 1
• Benefits: Improves inotropy with fewer vasoconstrictive complications than vasopressor-only therapy 1

Vasopressors

• Strong recommendation (Class 1, Level C-LD) for hypotension 1
• Often used as initial therapy due to immediate availability and rapid action
• May be used concurrently with high-dose insulin

Second-Line Therapies

Glucagon

• Reasonable to use (Class 2a, Level C-LD) for bradycardia or hypotension 1
• Mechanism: Activates adenylate cyclase through a beta-receptor independent pathway 2
• Dosing:
  • Bolus: 3-10 mg IV (0.05-0.15 mg/kg) administered slowly over 3-5 minutes
  • Maintenance: 3-5 mg/hour (0.05-0.10 mg/kg/hour) infusion 1
  • Titrate to hemodynamic response
• Important considerations:
  • Ensure adequate supply (may require >100 mg over 24 hours) 1
  • Common side effect: vomiting (protect airway in CNS-depressed patients) 1
  • Effectiveness confirmed in clinical studies regardless of beta-blockade 3

Third-Line Therapies

Calcium

• May be reasonable (Class 2b, Level C-LD) for refractory shock 1
• Dosing:
  • Initial: 0.3 mEq/kg (0.6 mL/kg of 10% calcium gluconate or 0.2 mL/kg of 10% calcium chloride) IV over 5-10 minutes
  • Maintenance: 0.3 mEq/kg/hour infusion 1
  • Titrate to hemodynamic response
  • Monitor ionized calcium levels (avoid levels >2× upper limit of normal)
• Requires central venous access for sustained infusion

Electrical Pacing

• May be reasonable (Class 2b, Level C-LD) for beta blocker-induced bradycardia 1

Hemodialysis

• May be reasonable (Class 2b, Level C-LD) specifically for atenolol or sotalol poisoning 1

Refractory Cases

VA-ECMO (Veno-Arterial Extracorporeal Membrane Oxygenation)

• Reasonable to use (Class 2a, Level C-LD) for life-threatening beta blocker poisoning with cardiogenic shock refractory to pharmacological interventions 1
• Consider early if patient shows signs of deterioration despite maximal medical therapy

Therapies Not Recommended

Intravenous Lipid Emulsion

• Not likely to be beneficial (Class 3: No Benefit, Level C-LD) for life-threatening beta blocker poisoning 1

Clinical Pearls and Pitfalls

1. Early recognition is critical: Beta blocker overdose presents with bradycardia, hypotension, and cardiogenic shock 1, 2

2. Monitoring considerations:

   • Frequent glucose monitoring is essential during insulin therapy
   • Moderate hypokalemia is expected and should not prompt aggressive repletion 1
   • Central venous access is needed for sustained calcium or concentrated dextrose infusions

3. Treatment escalation:

   • Begin with vasopressors for immediate effect
   • Rapidly initiate high-dose insulin therapy
   • Add glucagon if response is inadequate
   • Consider calcium for refractory cases
   • Early consideration of VA-ECMO for deteriorating patients

4. Special considerations:

   • Glucagon may interact with beta-blockers, causing transient increases in pulse and blood pressure 4
   • Ensure adequate glucagon supply before initiating therapy
   • Protect airway before glucagon administration in patients with CNS depression

By following this algorithmic approach to beta blocker overdose management, clinicians can optimize patient outcomes in these potentially fatal poisonings.