What is the appropriate emergency treatment for a patient with beta‑blocker overdose?

Emergency Treatment for Beta-Blocker Overdose

High-dose insulin euglycemia therapy is the first-line treatment for beta-blocker overdose with refractory shock, with glucagon as an equally reasonable alternative, both administered alongside vasopressor support and standard resuscitation measures. 1, 2, 3

Immediate Stabilization

• Establish continuous cardiac monitoring, secure intravenous access, and assess airway protection according to standard ACLS protocols 2
• Consider early intubation before administering glucagon due to high risk of vomiting and aspiration 2, 3
• Place arterial line for continuous blood pressure monitoring in severe cases 2

First-Line Pharmacologic Therapy

High-Dose Insulin Euglycemia (Preferred, Class I)

This is the most strongly recommended antidote therapy for refractory shock from beta-blocker poisoning. 1, 3

Dosing protocol:

• Initial bolus: 1 U/kg regular insulin IV together with 0.5 g/kg dextrose IV 1, 2, 3
• Continuous infusion: 1 U/kg/hour insulin (titrate up to 10 U/kg/hour as needed) with concurrent 0.5 g/kg/hour dextrose 1, 2, 3
• Mechanism: Enhances myocardial contractility and energy utilization independent of β-receptor activity 2, 3

Critical monitoring requirements:

• Check glucose every 15 minutes during initial titration, then hourly once stable; target 100-250 mg/dL 2, 3
• Monitor potassium frequently—insulin drives potassium intracellularly 2, 3
• Target potassium 2.5-2.8 mEq/L; do NOT aggressively replace above this level as it can precipitate fatal arrhythmias 2, 4, 3
• Use central venous access when dextrose concentration exceeds 10% 2, 4

Glucagon (Alternative First-Line, Class IIa)

Glucagon is equally reasonable as first-line therapy and bypasses blocked β-receptors by directly activating adenyl cyclase. 1, 2

Dosing protocol:

• Initial bolus: 3-10 mg IV over 3-5 minutes 1, 2, 5, 6
• Continuous infusion: 3-5 mg/hour (0.05-0.10 mg/kg/hour), titrated to hemodynamic response 2, 6
• Supply planning: Anticipate needing >100 mg in first 24 hours; ensure early pharmacy availability 2

Important caveats:

• Secure airway BEFORE glucagon administration due to high vomiting risk 2, 3
• Monitor for tachyphylaxis with prolonged use 2
• Nausea and vomiting are common side effects 6, 7

Vasopressor Support (Class I)

• Begin vasopressor therapy immediately for hypotension while preparing insulin or glucagon 1, 2
• Preferred agents: Norepinephrine for vasoplegic shock; epinephrine for additional inotropic support (epinephrine more effective than dopamine) 2, 3, 8
• High-dose catecholamines alone are often insufficient due to β-receptor blockade but provide survival benefit 2, 8

Second-Line Therapies

Calcium Administration (Class IIb)

• Dose: 0.3 mEq/kg calcium gluconate or calcium chloride IV over 5-10 minutes 2, 3
• Continuous infusion: 0.3 mEq/kg/hour, titrated to hemodynamic response 2
• Monitor ionized calcium; avoid levels >1.5-2× upper limit of normal 2
• Requires central venous access for sustained infusions 2
• Evidence is weaker for beta-blockers compared to calcium channel blocker toxicity 3

Atropine (Class IIb)

• Dose: 0.5-1 mg IV every 3-5 minutes, up to 3 mg total; pediatric dose 0.02 mg/kg 1, 2, 5
• Often ineffective in severe beta-blocker overdose but may be reasonable for symptomatic bradycardia 1, 2

Temporary Cardiac Pacing (Class IIb)

• Consider transcutaneous or transvenous pacing for refractory bradycardia or heart block, particularly in sotalol toxicity 1, 2, 5

Rescue Therapy for Refractory Cases

Venoarterial Extracorporeal Membrane Oxygenation (Class IIa)

• Indicated for cardiogenic shock unresponsive to maximal pharmacologic therapy (insulin, glucagon, vasopressors, calcium) 1, 3, 8
• Early consultation with medical toxicologist and ECMO team is critical 2
• Associated with improved survival in observational studies and case series 1, 8

Special Considerations for Specific Beta-Blockers

Atenolol and Sotalol (Water-Soluble Agents)

• Consider hemodialysis for massive overdoses due to dialyzability 1, 2, 5, 8
• Sotalol requires 12-hour monitoring period due to QT prolongation and arrhythmia risk 9
• Overdrive cardiac pacing may be needed for sotalol-induced torsades de pointes 8

Sustained-Release Formulations

• Expect prolonged toxicity; extend monitoring and treatment duration accordingly 2
• Monitor for at least 8 hours for sustained-release preparations 9

Contraindicated or Not Recommended Therapies

Avoid these common pitfalls:

• Intravenous lipid emulsion therapy: Explicitly NOT recommended (Class III, no benefit) for beta-blocker poisoning 1, 3, 8
• Dopamine as first-line vasopressor: Less effective than epinephrine/norepinephrine and may diminish glucagon efficacy 2, 3
• Aggressive potassium replacement: Maintain low-normal potassium (2.5-2.8 mEq/L) to prevent fatal arrhythmias 2, 4, 3
• Underdosing insulin: Standard insulin doses are ineffective; the "high-dose" designation is critical 3

Gastric Decontamination

• Consider activated charcoal if patient presents within 1-2 hours of ingestion and airway is protected 9, 8
• Do NOT induce emesis 9
• Do not delay transportation to administer charcoal 9

Treatment Algorithm Summary

1. Immediate: Cardiac monitoring, IV access, airway assessment, consider intubation before glucagon 2
2. First-line: High-dose insulin (1 U/kg bolus + 1 U/kg/hour infusion with dextrose) OR glucagon (3-10 mg bolus + 3-5 mg/hour infusion) PLUS vasopressors (norepinephrine/epinephrine) 1, 2, 3
3. Second-line: Calcium (0.3 mEq/kg), atropine (0.5-1 mg), consider pacing 1, 2
4. Rescue: VA-ECMO for refractory shock 1, 3
5. Special cases: Hemodialysis for atenolol/sotalol massive overdose 1, 2