Makindo Medical Notes

⚠️ 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

• Flumazenil – BNF
• TOXBASE guidance (UK National Poisons Information Service).