⚠️ Flumazenil should be used only in very specific circumstances (e.g. severe benzodiazepine toxicity where ventilation is being considered).
✅ Ensure airway is secure, IV access is established, and the patient is on a cardiac monitor before administration.
❌ It may provoke seizures, especially in mixed overdoses (e.g. TCAs) or chronic benzodiazepine users. Always seek senior/expert advice before use.
📖 About
Always check the BNF link here for current guidance.
- 💉 Competitive benzodiazepine receptor antagonist (acts at GABA-A receptor sites).
- ⚡ Reverses sedation and respiratory depression caused by benzodiazepines.
- ❗ High seizure risk: not routinely recommended in overdose management.
⚡ Action
- Displaces benzodiazepines from GABA-A receptors → rapid reversal of sedation, anxiolysis, and respiratory depression.
- Onset: within 1–2 minutes. Peak effect: 6–10 minutes. Duration: ~30–60 minutes (shorter than many benzodiazepines).
🎯 Indications
- Reversal of severe benzodiazepine-induced respiratory depression where airway/ventilation is at risk.
- May be used in procedural sedation (post-op anaesthetic recovery, endoscopy units).
- Not recommended for routine use in suspected or confirmed overdose unless very specific criteria are met.
- Not to be used as a diagnostic test for benzodiazepine ingestion.
💊 Dose (Adults, IV)
- Initial: 200 micrograms (0.2 mg) IV over 15 seconds.
- Titration: If required, further 100 micrograms (0.1 mg) at 60-second intervals.
- Usual effective dose: 300–600 micrograms.
- Maximum dose: 1–2 mg (usually given in ITU/monitored setting).
- ❗ Re-sedation is common as flumazenil has a shorter half-life than most benzodiazepines → may require repeated doses or infusion.
🔄 Interactions
- 🚫 Tricyclic antidepressants (TCA) co-ingestion: Flumazenil may precipitate seizures → avoid.
- ❗ Caution in mixed overdoses with drugs that lower seizure threshold (e.g. bupropion, theophylline, isoniazid).
⚠️ Cautions
- Seizure disorders or epilepsy.
- Head injury (may precipitate raised ICP from agitation/seizures).
- Chronic benzodiazepine use (may precipitate acute withdrawal and seizures).
- Not for use as a diagnostic test in overdose.
🚫 Contraindications
- History of recent seizures or at high risk of seizures.
- Status epilepticus.
- Alcohol or benzodiazepine withdrawal (risk of provoking seizures or delirium tremens).
💥 Side Effects
- Seizures (most feared complication).
- Dizziness, headache, flushing.
- Nausea, vomiting.
- Arrhythmias, palpitations.
- Rare: anaphylaxis.
📌 Clinical Pearls
- Always manage airway, breathing, and circulation before considering antidotes.
- Supportive care and ventilation are usually safer than flumazenil in overdose.
- If used, must be in a monitored / critical care setting with immediate resuscitation facilities.
- Best reserved for iatrogenic benzodiazepine sedation (e.g. procedural sedation) rather than overdose.
📚 References
