Pharm 101: Flumazenil

Class

Benzodiazepine antagonist

Pharmacodynamics

• Competitive antagonist for benzodiazepine binding site on GABA-A receptor
• Reverses sedative effects of benzodiazepines
• Unpredictable reversal of respiratory depression

Pharmacokinetics

• IV administration
• Rapid onset
• Rapid hepatic clearance
  • Short half-life 1 hour

Clinical uses

• Reversing CNS depressant effects of benzodiazepine overdose
• Hasten recovering following use of drugs in anaesthetic and diagnostic procedures

Adverse effects

• Agitation, confusion, dizziness, nausea
• Severe precipitated abstinence syndrome in those with benzodiazepine dependence
• Recurrence of sedation due to short half-life
  • Half-life of benzodiazepines if significantly greater
  • Repeated administration often necessary
• Seizures and cardiac arrhythmias may occur if patient has co-ingested TCAs with benzodiazpines

Further reading

• Buttner R. Pharm 101: Midazolam. LITFL
• Buttner R. Pharm 101: Diazepam. LITFL

References

• Katzung BG. Basic and Clinical Pharmacology. 14e. 2018: 390, 393