Flumazenil

Flumazenil is a competitive benzodiazepine antagonist with a limited role in the management of benzodiazepine poisoning. Usually to reverse procedural sedation, accidental paediatric ingestion with compromise, and rarely to help make a diagnosis of benzodiazepine overdose or if a patient’s airway is compromised without quick access to intubation equipment. The main hesitation for its use relates to dependency of benzodiazepines and mixed overdoses which if the benzodiazepine is reversed my precipitate seizures which will be difficult to control.

Administration:

• Only administer in an area that can manage potential seizures
• Adult dose = 0.1 – 0.2 mg IV and repeat every minute until there is reversal (max dose not exceeding 2mg)
• Paediatric dose = 0.01 – 0.02 mg/kg, repeat every minute.
• Re-sedation is likely to occur at 90 minutes whereupon further doses will be required.
• Sometimes a flumazenil infusion is warranted. This decision needs to be weighed up with the ability for a ward to manage an infusion and with large adult ingestions it can be easier, quicker and potentially safer to intubate and transfer to ICU

Contraindications:

• Known Seizure disorder
• Known or suspected co-ingestion of a pro-convulsant
• Known or suspected benzodiazepine dependance
• QRS prolongation on the ECG to suggest a possible co-ingestion with a sodium channel blocking drug (i.e. TCA)

References

• The flumazenil in benzodiazepine intoxication multicenter study group. Treatment of benzodiazepine overdose with flumazenil. Clinical Therapeutics 1992; 14:978-995.
• Ngo AS, Anthony CR, Samuel M et al.  Should a benzodiazepine antagonist be used in unconscious patients presenting to the emergency department? Resuscitation 2007; 74(1):27-37.
• Seger D.  Flumazenil – treatment or toxin. Journal of Toxicology-Clinical Toxicology 2004; 42(2):209-216.