Flumazenil
Romazicon
Benzodiazepine receptor antagonist (GABA-A α-subunit competitive)
Competitively binds benzodiazepine site on GABA-A receptor → displaces benzo agonists → reverses sedation, respiratory depression, amnesia.
Indications
- •Reversal of benzodiazepine-induced sedation (procedural or surgical)
- •Suspected benzo overdose (with caveats — see pearls)
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Conscious sedation reversal | 0.2 mg IV over 15 sec; repeat 0.2 mg q1 min up to 1 mg total (typical effective: 0.6-1 mg) | — |
| Suspected overdose (caution) | 0.2 mg IV; repeat to 3 mg total max — withhold if seizure risk | — |
| Pediatric | 0.01 mg/kg IV (max 0.2 mg/dose), repeat q1 min up to 1 mg total | — |
Pharmacokinetics
Onset 1-2 min IV; peak ~6-10 min; half-life ~1 hr (SHORTER than most benzos — re-sedation risk).
Hemodynamic effects
Minimal direct effect; sympathetic activation possible if patient resedates.
Side effects
- !Re-sedation (because flumazenil half-life << midazolam/diazepam half-life)
- !Seizures (especially in chronic benzo users — abrupt withdrawal)
- !Anxiety, agitation, panic on emergence
- !Withdrawal symptoms (chronic benzo dependence)
- !Cardiac arrhythmias (esp. with co-ingested TCAs — often fatal)
Contraindications
- ×Chronic benzo dependence (precipitates seizure / withdrawal)
- ×TCA co-ingestion (relative — risk of seizure + arrhythmia)
- ×Increased ICP without secured airway (seizure → ↑ ICP)
- ×Known epilepsy treated with benzos
Clinical pearls
- ★RE-SEDATION RISK: midazolam half-life 2-6 hr, diazepam 24-48 hr; flumazenil 1 hr. Patient must be observed minimum 2 hr post-flumazenil; redose if re-sedates.
- ★OVERDOSE CAUTION: most benzo overdoses don't need flumazenil — supportive care (airway, breathing) is safer than precipitating seizures from co-ingested TCA, cocaine, or chronic benzo dependence.
- ★PROCEDURAL SEDATION RESCUE: useful when over-sedation in a patient with no chronic benzo history; titrate slowly.
- ★PARADOXICAL DISINHIBITION reversal in elderly: occasional indication (rare).
Other drugs in Benzodiazepines & Reversal
- Midazolam
GABA-A potentiation at benzodiazepine receptor.
- Lorazepam
Allosteric positive modulator at GABA-A receptors → ↑frequency of Cl⁻ channel opening → membrane hyperpolarization. Hypnotic, anxiolytic, anticonvulsant, anterograde amnesia. Glucuronidated only — no CYP metabolism — useful in liver disease.
- Diazepam
Allosteric positive modulator at GABA-A. Hypnotic, anxiolytic, anticonvulsant, skeletal-muscle relaxant. Produces highly lipid-soluble + active metabolites (desmethyldiazepam, oxazepam, temazepam) → very long total duration in elderly + chronic dosing.
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