Benzodiazepine toxicity

Background

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

Clinical Features

1. Somnolence, slurred speech, ataxia (similar to ETOH intoxication)
2. Paradoxical reaction (more common in hyperactive children, psychiatric patients)
3. Hypotension
4. 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

1. GI decontamination
   1. Activated Charcoal x1
2. Mechanical ventilation if necessary
3. Flumazenil
   1. Controversial
      1. May prevent need for mechanical ventilation; may precipitate benzo-withdrawal seizure
   2. Indication:
      1. Consider (though controversial) for coma reversal
   3. Contraindications:
      1. Suspected or known physical dependence on benzodiazepines
      2. Suspected TCA overdose
      3. Co-ingestion of seizure-inducing agents
      4. Known seizure disorder
      5. Suspected increased intracranial pressure
   4. Dosing
      1. 0.2mg IV; may repeat q1min (max dose 3mg)
   5. Flumazenil-Induced Seizure
      1. Treat with phenobarbital or propofol; benzodiazepines will not work
4. Withdrawal
   1. High risk - GABA activity withdrawn
      1. CNS excitation:agitation, tremor, hallucinations, seizures
      2. Autonomic Instability: tachycardia, hypertension, hyperthermia, diaphoresis

Disposition

• Consider discharge after 6hr obs

See Also

• Sedative/Hypnotic
• Benzodiazepines