Benzodiazepine toxicity

Background

• Isolated benzodiazepine overdose has low morbidity/mortality
  • Coingestion or parenteral administration accounts for vast majority of deaths

Clinical Features

• Somnolence, slurred speech, ataxia (similar to ETOH intoxication)
• Paradoxical reaction (more common in hyperactive children, psychiatric patients)
• Hypotension
• Respiratory depression

Differential Diagnosis

Sedative/hypnotic toxicity

• Absinthe
• Barbiturates
• Benzodiazepines
  • Flunitrazepam (Rohypnol)
• Chloral hydrate
• Gamma hydroxybutyrate (GHB)
• Baclofen toxicity
• Opioids
  • Lomotil toxicity
  • Loperamide toxicity
• Toxic alcohols
  • Ethanol
  • Ethylene glycol
  • Isopropyl alcohol
  • Methanol
• Xylazine toxicity

Management

• GI decontamination
  • Activated Charcoal x1
• Mechanical ventilation if necessary
• Flumazenil
  • Controversial
    • May prevent need for mechanical ventilation; may precipitate benzo-withdrawal seizure
  • Indication:
    • Consider (though controversial) for coma reversal
  • Contraindications:
    • Suspected or known physical dependence on benzodiazepines
    • Suspected TCA overdose
    • Co-ingestion of seizure-inducing agents
    • Known seizure disorder
    • Suspected increased intracranial pressure
  • Dosing
    • 0.2mg IV; may repeat q1min (max dose 3mg)
  • Flumazenil-Induced Seizure
    • Treat with phenobarbital or propofol; benzodiazepines will not work
• Withdrawal
  • High risk - GABA activity withdrawn
    • CNS excitation:agitation, tremor, hallucinations, seizures
    • Autonomic Instability: tachycardia, hypertension, hyperthermia, diaphoresis

Disposition

• Consider discharge after 6hr obs

See Also

• Sedative/Hypnotic
• Benzodiazepines