Beta-blocker toxicity

Background

• Coingestion with CCB, cyclics, and neuroleptics increases mortality
• Agents with membrane-stabilizing activity are esp lethal
  • Prolongs QT > dysrhythmias
    • Propranolol
    • Sotalol

Diagnosis

• Cardiac
  • Bradycardia
  • Hypotension
  • Ventricular dysrhythmias
• CNS
  • Mental status change
    • Delirium, coma
  • Seizure (esp w/ propranolol)
• Other
  • Hypoglycemia (uncommon in adults)
  • Bronchospasm (uncommon)

Work-Up

• ECG
  • PR prolongation
  • Bradycardia
  • QT prolongation
  • Any bradydysrhythmia
• Glucose
• Chemistry

DDx

• Calcium-channel blockers
  • Unlikely to cause CNS changes
  • Hyperglycemia is more common
• Digoxin
  • Nausea/vomiting is more common
• Clonidine
  • Miosis, somnolence
• Cholinergic agents
  • SLUDGE

Management

• Consider charcoal if present within 2 hr of ingestion

• Bradycardia (symptomatic)
  • Atropine 0.5-1mg q3-5min up to 0.04mg/kg
• Hypotension
  • IV fluids
• Hypoglycemia
  • Adult - D50
  • Ped - 2.5mL/kg of D10

If IV fluid and atropine are not sufficient then consider:

• Glucagon
  • Half-life is 20min
  • Consider concurrent administration of ondansetron (causes n/v)
  • Adult: 5mg IV bolus over one minute
  • Ped: 50mcg/kg
  • Rebolus if no response after 10min
  • If effective start infusion at:
    • Adult: 2-5mg/hr
    • Ped: 70mcg/kg/hr

• High dose insulin and glucose
  • Augments myocardial contraction

• Vasopressors
  • Consider if all of above has failed
  • Epinephrine
    • Adult: Start 1 mcg/min and titrate to MAP=60
    • Ped: Start 0.1mcg/kg/min

• Hemodialysis
  • Only effective for atenolol, sotalol

Disposition

• Admit all symptomatic patients
• Admit all sotalol ingestions (long half-life)
• Observe all others for ~ 6hr

Source

Rosen's