What is the protocol for beta (beta blocker) reversal in cases of overdose or toxicity?

Beta-Blocker Overdose Management Protocol

High-dose insulin therapy is the first-line antidote for beta-blocker overdose with refractory hypotension, with a Class 1, Level B-NR recommendation from the American Heart Association. 1

Initial Stabilization and Treatment Algorithm

1. Initial Stabilization

   • Begin with vasopressors for immediate blood pressure support
   • Epinephrine or norepinephrine are preferred over dopamine 1
   • Atropine may be used for bradycardia (0.5-1.0 mg IV every 3-5 minutes, up to 3 mg in adults) 1

2. First-Line Antidote: High-Dose Insulin Therapy

   • Initial bolus: 1 U/kg IV regular insulin
   • Concurrent dextrose: 0.5 g/kg IV
   • Maintenance infusion: 0.5-1 U/kg/hour, titrated to hemodynamic response
   • Dextrose infusion: 0.5 g/kg/hour to maintain glucose 100-250 mg/dL 1

3. Second-Line Therapy: Glucagon

   • Initial dose: 2-10 mg IV bolus
   • Maintenance: 1-15 mg/hour infusion 1
   • Note: Commonly causes vomiting (concern in altered mental status) 1

4. Refractory Cases

   • Calcium: 0.3 mEq/kg IV initial dose, followed by 0.3 mEq/kg/hour infusion (Class 2b, Level C-LD) 1
   • VA-ECMO for life-threatening cases with cardiogenic shock refractory to pharmacological interventions 1
   • Hemodialysis may be reasonable for life-threatening atenolol or sotalol poisoning 1

Monitoring Requirements

• Glucose monitoring: Every 15 minutes initially during high-dose insulin therapy 1
• Potassium monitoring: Regular checks with expectation of moderate hypokalemia 1
• Continuous cardiac monitoring: Essential throughout treatment 1
• End-organ perfusion assessment: Monitor urine output, mental status, and peripheral perfusion 1
• Laboratory assessment: Regular checks of glucose, potassium, calcium, and arterial blood gases 1

Important Considerations and Pitfalls

• Central venous access: Required for concentrated dextrose solutions 1
• Avoid delaying insulin therapy: This is now considered first-line, not glucagon 1
• Avoid aggressive potassium repletion: Moderate hypokalemia is expected with insulin therapy 1
• Avoid certain antiarrhythmics: Class IA, IC, or III antiarrhythmics may worsen cardiac toxicity 1
• Lipid emulsion therapy: Not recommended for beta-blocker poisoning (Class 3: No Benefit, Level C-LD) 1

Glucagon Considerations

• Glucagon increases heart rate, myocardial contractility, and improves atrioventricular conduction by bypassing the beta-receptor site 2
• Monitor for side effects including nausea, vomiting, hypokalemia, and hyperglycemia 2
• If the patient develops dramatic increase in blood pressure with glucagon, phentolamine mesylate can be effective in lowering blood pressure temporarily 3

Treatment Escalation Pathway

1. Vasopressors → 2. High-dose insulin therapy → 3. Add glucagon if response inadequate → 4. Consider calcium for refractory cases → 5. Consider VA-ECMO for refractory shock 1

This protocol prioritizes the most recent and highest quality evidence from the American Heart Association, which now recommends high-dose insulin as first-line therapy over the traditionally used glucagon for beta-blocker overdose with significant cardiovascular compromise.