Bedside Snapshot
- Use It For
- Benzodiazepine sedation or anesthesia reversal; selected pure benzodiazepine overdose with respiratory depression, in a non-dependent patient with no seizure risk
- Adult Dose
- Sedation reversal: 0.2 mg IV over 15 sec q1 min (max 1 mg)
- Overdose: 0.2 mg IV, titrated to max 1 mg (label: up to 3 mg)
- Resedation: ≤1 mg at 0.2 mg/min (0.5 after overdose), every ≥20 min, max 3 mg/hr
- Pediatric Dose
- Sedation reversal, age 1 yr and older: 0.01 mg/kg IV (max 0.2 mg), every 1 min up to 4 more doses (max total 0.05 mg/kg or 1 mg, whichever is lower). Overdose: not established
- Onset / Duration
- IV: onset 1–2 min, peak 6–10 min. Duration dose-dependent, often shorter than the benzodiazepine's; resedation 19–50 min after dosing in children
- Do Not Give / Hold If
- Benzodiazepine given for status epilepticus or raised intracranial pressure; signs of serious cyclic antidepressant overdose (wide QRS, dysrhythmia, seizures); seizures likely from any cause; hypersensitivity
- Watch For
- Seizures (chronic benzodiazepine users, mixed overdoses); resedation and hypoventilation as it wears off (RR, SpO₂, EtCO₂); agitation and withdrawal; dysrhythmias
- Reversal / Rescue
- Seizure: airway, then higher-than-usual benzodiazepine, barbiturate or propofol; no more flumazenil. No response at 1 mg: reassess other causes. Label: benzodiazepines unlikely only after 5 mg, no response at 5 min.
- Must Remember
- Ventilate first and titrate slowly. Not for undifferentiated coma: it can unmask seizures and withdrawal, and it often wears off before the benzodiazepine does
Indications
Emergency & Prehospital
- Known or suspected benzodiazepine overdose: Pure benzodiazepine poisoning with significant CNS or respiratory depression. The patient is not dependent and has no seizure or dysrhythmia risk. Labeled for adults. Airway and ventilation come first.
ED / ICU / Transport
- Procedural sedation reversal: adults and children 1 yr and older (labeled), e.g. after midazolam
- Respiratory depression during sedation: breathing stays inadequate even after stimulation, oxygen and positive-pressure ventilation
- General anesthesia reversal: adults only. Use it when sedation outlasts the procedure (labeled)
Other Uses
- Z-drug toxicity (zolpidem, zopiclone): the same seizure cautions apply. Supportive care comes first (off-label).
- Hepatic encephalopathy in cirrhosis: short-term improvement only, with no effect on mortality (off-label).
- Not indicated: undifferentiated coma, cardiac arrest, ICU sedation diagnosis, dependence or withdrawal
Dosing & Administration
Pediatric doses come from AHA/AAP 2025 when it states a dose, then from the NASEMSO National Model EMS Clinical Guidelines v3.0 (2022), then from the US label. No dose appears where none of them gives one. A pediatric maximum never goes above the adult maximum dose (NASEMSO Universal Care Guideline, p. 13). Unless a dose is marked labeled, it is off-label. When the label differs from the lead dose, a "Differs from FDA label" note follows right after it.
Available Forms
- Flumazenil injection (generic): 0.1 mg/mL in 5 mL (0.5 mg) and 10 mL (1 mg) multiple-dose vials. 0.2 mg = 2 mL; 0.3 mg = 3 mL; 0.5 mg = 5 mL.
- IV use only. The brand Romazicon is no longer sold in the US.
Adult Dosing
| Indication | Dose & Route | Repeat / Max | Notes |
|---|---|---|---|
| Reversal of procedural sedation or general anesthesia | 0.2 mg IV over 15 sec (2 mL). Not at target 45 sec later: 0.2 mg IV every 60 sec | Up to 4 repeat doses; max 1 mg total | Of responders, about half needed 0.4–0.6 mg and half 0.8–1 mg. Give small injections and stop at the level of consciousness you want. |
| Resedation after sedation or anesthesia reversal | Up to 1 mg IV given as 0.2 mg/min | Repeat no sooner than every 20 min; max 1 mg per treatment and 3 mg in any 1 hr | The label allows repeating the initial dose at 30 and possibly 60 min. |
| Known or suspected benzodiazepine overdose | 0.2 mg IV over 30 sec, titrated to response | Max 1 mg cumulative (house lead); the label allows 3 mg, and up to 5 mg for partial responders at 3 mg | Differs from FDA label: the label gives 0.2 mg IV over 30 sec, then 0.3 mg after 30 sec, then 0.5 mg over 30 sec at 1-min intervals to 3 mg cumulative; partial responders at 3 mg may receive up to 5 mg. The label says 75% of responders needed 1–3 mg. If there is no response 5 min after a cumulative 5 mg, the label says the sedation is likely not mainly from a benzodiazepine. Opioid co-ingestion: naloxone first. Titrate slowly. |
| Resedation after overdose reversal | Up to 1 mg IV given as 0.5 mg/min | Repeat no sooner than every 20 min; max 1 mg per treatment and 3 mg in any 1 hr | Stay monitored until stable. |
| High-risk patient (benzodiazepine tolerance or possible dependence) | Titrate at 0.1 mg/min IV, aiming for the smallest effective dose | Do not exceed the indication's max; aim lower. Withdrawal-like events were 2–5 times more frequent above 1 mg. Wait longer than 1 min between doses | A dose takes 6–10 min to act. Physical dependence: no dose has been studied. |
Pediatric Dosing
| Indication | Dose (per kg) & Route | Max Single / Max Total | Notes |
|---|---|---|---|
| Reversal of procedural sedation (age 1 yr and older) | 0.01 mg/kg IV over 15 sec. Not at target 45 sec later: 0.01 mg/kg IV every 60 sec | Max 0.2 mg per dose; up to 4 repeat doses; max total 0.05 mg/kg or 1 mg, whichever is lower | Mean total dose in the labeling trial was 0.65 mg; about half needed all 5 doses. |
| Benzodiazepine overdose | Not established in children | — | The label states safety and efficacy have not been established in pediatric patients for overdose. 2025 AHA Guidelines for CPR and ECC, Part 10 (children, COR 2a, LOE B-R) supports use in select children with pure benzodiazepine poisoning but gives no dose. Call the poison center (1-800-222-1222) or a toxicologist. |
| General anesthesia reversal | Not established in children | — | The label states safety and efficacy have not been established in pediatric patients for reversal of sedative effects of benzodiazepines used for induction of general anesthesia. |
| Infants under 1 yr and neonates | Not established under 1 yr | — | Not established for newborn resuscitation. |
10-fold tape error: The recalled AirLife Broselow Rainbow Tape (Revision 3, print version) lists flumazenil at 0.1 mg/kg, ten times the correct dose of 0.01 mg/kg (max 0.2 mg). Read up on Broselow tape and weight-based dosing.
Preparation & Administration
- Dilution: give the 0.1 mg/mL solution as supplied (see IV Compatibility). Discard any drawn-up syringe or mixture after 24 hr.
- Push rate and line: 0.2 mg over 15 sec for sedation reversal; each overdose dose over 30 sec. Use a freely running IV in a large vein; extravasation can cause local irritation.
- Before the first dose: secure the airway, ventilation and IV access. Confused, agitated patients who are waking up may go for the endotracheal tube and the IV lines. Do not give it until neuromuscular blockade is fully reversed.
Dosing Notes:
- Aim for adequate breathing. A fully awake, anxious patient is not the goal. With hepatic impairment, give smaller or less frequent repeat doses.
- No guideline gives a dose for continuous infusion. AHA 2025 restricts flumazenil to select adults with pure benzodiazepine respiratory depression and no seizure or arrhythmia risk (COR 2a). It names harm in those at risk (COR 3: Harm) (2025 AHA Guidelines for CPR and ECC, Part 10). A 2025 retrospective cohort (Kim et al.) found that infusion shortened time to consciousness only in hospitalized patients. It also increased adverse events, agitation among them. Use it only on direction from the poison center or a toxicologist.
Contraindications & Precautions
Contraindications
- Hypersensitivity to flumazenil or to benzodiazepines.
- A benzodiazepine given to control a potentially life-threatening condition (e.g. status epilepticus, raised intracranial pressure (ICP)).
- Signs of serious cyclic antidepressant overdose: twitching, rigidity or focal seizure; wide QRS, ventricular dysrhythmia or heart block; anticholinergic signs; cardiovascular collapse.
Precautions
- Seizure risk (do not use when seizures are likely from any cause): physical dependence (even after a few days of ICU sedation), recent repeated IV benzodiazepines, sedative or alcohol withdrawal, myoclonus or seizure before the dose, epilepsy, proconvulsant co-ingestants (cyclic antidepressants, bupropion, tramadol, cocaine).
- ICU patients: dependence often goes unrecognized. Do not use flumazenil to diagnose benzodiazepine sedation.
- Head injury, panic disorder, serious lung disease: flumazenil may bring on seizures or change cerebral blood flow. It may provoke panic, or hide respiratory failure that needs ventilation.
2025 AHA Guidelines, Part 10: Adults
- Naloxone first when combined opioid and benzodiazepine poisoning is suspected in an adult with respiratory depression or arrest (COR 2a, LOE B-NR).
- Select adults only: it can be effective in select adults, those with respiratory depression or arrest from pure benzodiazepine poisoning and no contraindications (COR 2a, LOE C-LD).
- No role in cardiac arrest from benzodiazepine poisoning (COR 3: No Benefit, LOE C-EO).
- Harm in adults at increased risk for seizures or arrhythmias (COR 3: Harm, LOE B-R).
- With undifferentiated coma and both the history and co-ingestants unknown, risks likely exceed benefit (Part 10, adult supportive text, same statement for children).
Hold / Reassess If
- Myoclonus, seizure, new wide QRS or dysrhythmia: stop and treat.
- Agitation, confusion, tremor, tachycardia or hypertension: stop titrating. The reversal is already enough.
- No response at 1 mg (house ceiling): stop titrating and reassess airway, ventilation, co-ingestants, hypoglycemia and hypoxia. That does not rule out a benzodiazepine cause. The label's conclusion needs no response 5 min after a cumulative 5 mg. Going above 1 mg is a clinician decision, and withdrawal and seizure risk rise with it.
FDA Boxed Warning: Seizures have been linked to flumazenil, most commonly in long-term benzodiazepine users and in overdoses that show serious cyclic antidepressant toxicity. Individualize the dose. Be ready to manage seizures.
Adverse Effects & Toxicity
Common
- Nausea and vomiting: 11%
- Dizziness, vertigo, ataxia: 10%
- Injection-site pain; agitation, anxiety, tremor, palpitations: 3–9%
- Sweating, headache, blurred or abnormal vision: 3–9%
- Flushing, fatigue, emotional lability, paresthesia: 1–3%
Serious / Life-Threatening
| Effect | Recognition | Management |
|---|---|---|
| Seizures (under 1% in trials; 6 of 446 in overdose trials, 4 after large cyclic antidepressant ingestions) | Myoclonus or generalized seizure, sometimes before waking | Airway and oxygen; a higher-than-usual benzodiazepine dose, then a barbiturate such as phenobarbital or propofol. No more flumazenil. Differs from FDA label: the label lists benzodiazepines, phenytoin or barbiturates; a toxicology review found no role for phenytoin in drug-induced seizures. |
| Resedation and recurrent hypoventilation (3–9% after sedation, 10–15% after anesthesia; profound in 1–3%) | Falling consciousness, respiratory rate or SpO₂; rising EtCO₂ | Ventilate; repeat doses no sooner than every 20 min (max 1 mg per treatment, 3 mg/hr); extend observation |
| Precipitated withdrawal | Agitation, confusion, lability, sensory distortion, tremor; more common above 1 mg | Stop titrating; reassurance; a barbiturate, benzodiazepine or other sedative if needed |
| Dysrhythmias (VT and junctional tachycardia in 2 of 446 overdose patients) | Continuous ECG; new tachycardia or wide QRS | Treat the rhythm; suspect cyclic antidepressant toxicity (sodium bicarbonate for wide QRS per protocol) |
Overdose & Toxicity Management
- Flumazenil itself: large IV doses in healthy volunteers without a benzodiazepine caused no serious effects. The harm comes from the reversal.
- Overdose trials: a meta-analysis of 13 randomized trials found more adverse events (28% vs 10%) and serious events (12 of 498 vs 2 of 492) than placebo. Those were mostly dysrhythmias and seizures.
- Opioid co-ingestion: flumazenil will not reverse an opioid. Give naloxone and ventilate.
Monitoring
| Parameter | When / How Often | Target / Act If |
|---|---|---|
| Clinical: RR, SpO₂, EtCO₂ | Continuously before, during and after dosing | Falling RR or SpO₂, or rising EtCO₂: ventilate with a bag-valve mask (BVM), then consider a repeat dose within the 20-min rule |
| Clinical: consciousness, airway reflexes | Before each dose, then frequently during observation | Target: arousable with adequate breathing. Resedation: support breathing, repeat per Adult Dosing |
| Clinical: seizures and ECG | Seizures: throughout. ECG: continuous in overdose, with baseline QRS | Myoclonus before dosing: withhold. Seizure after dosing: treat. Wide QRS, VT or heart block: do not give |
| Laboratory: glucose and co-ingestant screen | Altered mental status or overdose, per local protocol | No lab tracks flumazenil response; use the toxicology panel for co-ingestants |
| Observation after reversal | Sedation or anesthesia: up to 120 min (label). Overdose: until stable | Extend after a long-acting benzodiazepine (e.g. diazepam) or more than 10 mg of midazolam. No sedation 2 hr after a 1 mg dose makes serious resedation unlikely |
| Discharge after procedural sedation | Before release | Amnesia is not reliably reversed: written instructions; no driving, alcohol or non-prescription drugs for 24 hr |
Interactions & Compatibility
Clinically Significant Interactions
| Drug / Class | Effect | What To Do |
|---|---|---|
| Cyclic antidepressants and other proconvulsant co-ingestants | Reversal unmasks seizures and dysrhythmias the benzodiazepine suppressed | Do not give with signs of serious toxicity; keep sedated and ventilated |
| Long-term benzodiazepines; alcohol or sedative dependence | Precipitated withdrawal and seizures, dose-related (more above 1 mg) | Avoid. Tolerance only: titrate at 0.1 mg/min to the lowest total dose |
| Z-drugs (zolpidem, zopiclone); remimazolam | Also reversed; the zolpidem label warns of convulsions, and the remimazolam label says flumazenil should be immediately available | Same cautions as benzodiazepines; supportive care first |
| Opioids, ethanol, barbiturates, general anesthetics | Not reversed | Naloxone for opioids; airway and ventilatory support |
| Neuromuscular blockers | Waking a patient with residual paralysis | Give only after blockade is fully reversed |
IV Compatibility
- Diluents: D5W, lactated Ringer's and normal saline are all compatible. Discard mixtures after 24 hr.
- Y-site: The label gives no data. Flush, or give into a freely running compatible line. Verify with an institutional compatibility resource.
Special Populations
- Pediatrics: labeled only for procedural sedation reversal from age 1 yr. In the labeling trial, 7 of 60 fully alert children resedated 19–50 min after the first dose, and every one of them was aged 1–5 yr. The 2025 AHA Part 10 for children says flumazenil can be effective in select children with pure benzodiazepine poisoning (COR 2a, LOE B-R). Suspect opioid co-ingestion? Naloxone first (COR 2a, LOE C-EO). It has no role in arrest (COR 3: No Benefit, LOE C-EO), and it causes harm where seizure or arrhythmia risk is present (COR 3: Harm, LOE C-LD). Part 10 gives no pediatric dose.
- Neonates: not established under 1 yr or for newborn resuscitation. Reversing benzodiazepines given in labor is not recommended.
- Pregnancy: human studies are not adequate. Rabbits had embryo loss at about 200 times human exposure. Use it only when benefit clearly outweighs risk. Airway and ventilation come first.
- Lactation: it is unknown whether flumazenil enters human milk. Use caution.
- Older Adults: pharmacokinetics are not significantly altered. Usual reversal doses apply. Reduce the benzodiazepine dose instead.
- Renal Impairment: no specific adjustment is established. It is not significantly changed by CrCl under 10 mL/min or by hemodialysis.
- Hepatic Impairment: clearance falls to 40–60% of normal in mild to moderate impairment, and to 25% in severe impairment. The initial dose stays the same. Make repeat doses smaller or less frequent. Seizures have been reported in severe impairment.
- Obesity / Dosing Weight: adult doses are fixed, not weight-based. For children, 0.01 mg/kg per dose (max 0.2 mg), with a total max of 0.05 mg/kg or 1 mg, whichever is lower.
Field & Transport Considerations
- Scope: Paramedic, RN and critical-care transport where carried; varies by state and agency protocol.
- Prehospital Priorities: airway and BVM ventilation come first. Check glucose. If opioid co-ingestion is possible, naloxone goes first. Supportive care is the mainstay. Routine flumazenil is not recommended.
- Cardiac Arrest: no role in arrest from benzodiazepine poisoning. Run standard BLS/ACLS with effective ventilation.
- Storage & Stability: store at 25 °C (77 °F). Excursions of 15–30 °C (59–86 °F). Keep it in the vial until use.
- Carried Concentration: 0.1 mg/mL: 0.2 mg = 2 mL. Pediatric 0.01 mg/kg = 0.1 mL/kg (max 2 mL). Watch for the recalled Broselow tape.
- In Transport: the reversal may wear off before the benzodiazepine does. Resedation can start mid-transport.
- Handoff Essentials: time and size of each dose, total given, response, benzodiazepine or alcohol dependence, co-ingestants, baseline QRS, any seizure or agitation.
Clinical Pearls
Not a coma-cocktail drug: The unknown coma is not a flumazenil patient. In undifferentiated coma or mixed overdose it can unmask seizures and dysrhythmias, and beyond waking the patient it adds little. Ventilate. Keep it for pure benzodiazepine poisoning in someone low-risk and not dependent. Cardiac arrest is not its job.
Titrate, then wait: Did the last dose work yet? Each one needs 6–10 min to act, so give it that time. Small steps reach the target with less agitation and withdrawal.
Seizure after flumazenil: Benzodiazepines may need higher-than-usual doses. Barbiturates or propofol are the alternative. Do not give more flumazenil.
Exam discriminator: what flumazenil does not reverse:
- Opioids (use naloxone), ethanol, barbiturates, general anesthetics
- Amnesia, reliably
- For benzodiazepine respiratory depression, ventilation is the treatment
No response at 1 mg: Nothing at 1 mg? That is the house ceiling. It is not a label conclusion. Look again for co-ingestants, hypoglycemia, head injury or hypoxia. Only after 5 mg cumulative with no response at 5 min does the label call a benzodiazepine unlikely to be the main cause.
Pharmacology
Mechanism of Action
- Competitive antagonist at the benzodiazepine site of the GABA-A receptor. Agonist activity in humans is little or none.
- It reverses sedation, psychomotor impairment and ventilatory depression from benzodiazepines. Amnesia is reversed less completely.
- Ethanol, barbiturates, general anesthetics and opioids are all untouched.
Pharmacokinetics
| Route | Onset | Peak | Duration |
|---|---|---|---|
| IV | 1–2 min (80% response by 3 min) | 6–10 min | Short-lived and dose-dependent; often ends before the benzodiazepine's effect |
- Half-life: distribution 4–11 min; terminal 40–80 min (mean 54 min) in adults; about 40 min (20–75 min) in children.
- Metabolism: 99% is hepatic, producing an inactive de-ethylated free acid and its glucuronide. Clearance depends on hepatic blood flow.
- Elimination: 90–95% in urine, 5–10% in feces; under 1% unchanged. Protein binding / Vd: about 50%; Vd at steady state 0.9–1.1 L/kg.
Names & Classification
- Generic Name
- Flumazenil
- Brand Names
- Romazicon (discontinued in the US); generic flumazenil injection
- Pharmacologic Class
- Imidazobenzodiazepine benzodiazepine receptor antagonist
- Therapeutic Class
- Antidote; benzodiazepine reversal agent
- Controlled Substance
- Not controlled
- ISMP High-Alert
- No
- Look-Alike / Sound-Alike
- None commonly reported; the main error is the 10-fold pediatric dose (0.1 vs 0.01 mg/kg)
References
- Hikma Pharmaceuticals USA Inc. (2024). Flumazenil injection [prescribing information, with boxed warning] (revised December 2020; DailyMed version posted June 2024). DailyMed, National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=436f5616-9626-4b6a-9deb-2986444179d0
- Cao, D., Arens, A. M., Chow, S. L., et al. (2025). 2025 American Heart Association Guidelines for CPR and ECC, Part 10: Adult and Pediatric Special Circumstances of Resuscitation. Circulation, 152(16 suppl 2), S578–S672. https://cpr.heart.org/en/resuscitation-science/cpr-and-ecc-guidelines/adult-and-pediatric-special-circumstances-of-resuscitation
- American Society of Anesthesiologists Task Force on Moderate Procedural Sedation and Analgesia, et al. (2018). Practice guidelines for moderate procedural sedation and analgesia 2018. Anesthesiology, 128(3), 437–479. https://doi.org/10.1097/ALN.0000000000002043
- Coté, C. J., Wilson, S., American Academy of Pediatrics, & American Academy of Pediatric Dentistry. (2019). Guidelines for monitoring and management of pediatric patients before, during, and after sedation for diagnostic and therapeutic procedures. Pediatrics, 143(6), e20191000. https://doi.org/10.1542/peds.2019-1000
- Institute for Safe Medication Practices, American Society of Health-System Pharmacists, & Pediatric Pharmacy Association. (2026). Joint hazard alert! Action needed to address incorrect information on the Broselow Rainbow Tape (revised January 22, 2026). ECRI and ISMP. https://home.ecri.org/blogs/guidance-insights-tools/joint-hazard-alert-action-needed-to-address-incorrect-information-on-the-broselow-rainbow-tape
- Sharbaf Shoar, N., Bistas, K. G., Patel, P., & Saadabadi, A. (2024). Flumazenil. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK470180/
- Penninga, E. I., Graudal, N., Ladekarl, M. B., & Jürgens, G. (2016). Adverse events associated with flumazenil treatment for the management of suspected benzodiazepine intoxication: A systematic review with meta-analyses of randomised trials. Basic & Clinical Pharmacology & Toxicology, 118(1), 37–44. https://doi.org/10.1111/bcpt.12434
- Goh, E. T., Andersen, M. L., Morgan, M. Y., & Gluud, L. L. (2017). Flumazenil versus placebo or no intervention for people with cirrhosis and hepatic encephalopathy. Cochrane Database of Systematic Reviews, 2017(7), CD002798. https://doi.org/10.1002/14651858.CD002798.pub3
- Acacia Pharma, Inc. (2023). BYFAVO (remimazolam) for injection, prescribing information, section 5.1 (revised January 2023). DailyMed, National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=4e1838f2-b999-41a7-a761-d94f09aa531f
- sanofi-aventis U.S. LLC. (2022). AMBIEN (zolpidem tartrate) tablets, prescribing information, Overdosage (revised February 2022). DailyMed, National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c36cadf4-65a4-4466-b409-c82020b42452
- Chen, H.-Y., Albertson, T. E., & Olson, K. R. (2016). Treatment of drug-induced seizures. British Journal of Clinical Pharmacology, 81(3), 412–419. https://doi.org/10.1111/bcp.12720
- Kim, J., Kim, S. H., Choi, S. P., Zhu, J. H., Kim, S. W., Kwon, M. K., & Oh, J. H. (2025). Continuous flumazenil infusion and time to consciousness recovery in benzodiazepine poisoning: A retrospective cohort study. Journal of Clinical Medicine, 14(17), 5983. https://doi.org/10.3390/jcm14175983
Medical Disclaimer
- For Educational Purposes Only: This content is intended for educational reference and should not be used for clinical decision-making.
- Not a Substitute for Professional Judgment: Always consult your local protocols, institutional guidelines, and supervising physicians.
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