Benzodiazepine toxicity
Background
- Isolated benzodiazepine overdose has low morbidity/mortality
- Coingestion or parenteral administration accounts for vast majority of deaths
- Respiratory depression rare with overdose of oral agents
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
- Chloral hydrate
- Gamma hydroxybutyrate (GHB)
- Baclofen toxicity
- Opioids
- Toxic alcohols
- Xylazine toxicity
Evaluation
- Urine toxicology screen
- Most benzodiazepine screens look for oxazepam, which is a metabolite of diazepam and chlordiazepoxide. Therefore, lorazepam, alprazolam, and clonazepam are commonly missed.
- True positives: Oxazepam, temazepam, diazepam, alprazolam, triazolam
- False negatives: Lorazepam, clonazepam, midazolam
Management
- GI decontamination
- 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
Disposition
- Consider discharge after 6hr observation