Symptoms and signs
Benzodiazepines commonly cause drowsiness, ataxia, dysarthria and nystagmus. Coma, hypotension and respiratory depression occasionally occur but are seldom serious if these drugs are taken alone. Coma usually lasts only a few hours but in elderly people it may be more protracted and cyclical. Benzodiazepine respiratory depressant effects are more serious in patients with severe chronic obstructive airways disease. Benzodiazepines potentiate the effects of other central nervous system depressants including alcohol.
Management
- Maintain a clear airway and adequate ventilation if indicated.
- Give activated charcoal (50g for an adult, 1g/kg in a child) to alert patients who present within 1 hour of having ingested more than a potentially toxic amount.
- Patients who are asymptomatic at 4 hours are unlikely to develop symptoms.
- Supportive measures paying particular attention to airway and breathing as indicated by the patient's clinical state.
- Flumazenil (a benzodiazepine antagonist) can only be used in pure benzodiazepine overdose. However it is not licensed for such use and it has a short half-life (about 40 minutes). Flumazenil is only to be used after discussion with ED consultant.
Flumazenil is Not to be used in Mixed Overdose or as a “Diagnostic” Test. Flumazenil lowers the seizure threshold.