flumazenil at a glance
Medicine class
Benzodiazepine-receptor antagonist and antidote
Usual setting
Given intravenously by an experienced clinician in a monitored clinical setting
Important limitation
It does not reverse sedation caused by substances that do not act at benzodiazepine receptors
After treatment
Drowsiness or breathing suppression can return because some benzodiazepines last longer than flumazenil
What is flumazenil used for?
The selected product is licensed for complete or partial reversal of central benzodiazepine sedation.
Ending benzodiazepine-induced or maintained sedation during general anaesthesia in hospital.
Reversing sedation after short diagnostic or therapeutic procedures.
Reversing conscious sedation in children older than one year.
Reversing central benzodiazepine effects in intensive care, including helping restore spontaneous breathing.
Diagnosing and treating intoxication or overdose caused only or mainly by benzodiazepines.
How does flumazenil work?
Flumazenil competes with benzodiazepines and related substances at their binding site on GABA-A receptors, blocking their sedative effects. It does not neutralise substances acting through other mechanisms, and its effect may wear off before the benzodiazepine effect does.
flumazenil preparations and strengths
Injection
Route: Parenteral
Strengths: 100 micrograms/mL
How to take flumazenil
Flumazenil is not taken by mouth or self-administered. A clinician gives it into a vein as an injection or infusion, with monitoring and resuscitation facilities available.
The solution should be clear, colourless and practically free from particles.
Do not drive, operate machinery or undertake demanding activities for 24 hours after treatment because sedation may return.
flumazenil side effects
Common or expected effects
- Nausea, vomiting or hiccups
- Dizziness or headache
- Anxiety, agitation or emotional changes
- Tremor, dry mouth or tingling
- Double vision or increased tearing
- Flushing, blood-pressure changes or palpitations
- Sweating or injection-site pain
Get urgent medical advice
- Severe allergic reaction, including facial or throat swelling and difficulty breathing
- Convulsions, particularly in susceptible patients
- Significant breathing difficulty or chest pain
- Severe withdrawal symptoms, agitation or confusion after reversal
flumazenil in pregnancy
Human pregnancy risk is not established. Flumazenil should be used only when the expected clinical benefit outweighs potential fetal risk; emergency use is not specifically contraindicated.
flumazenil while breastfeeding
It is not known whether flumazenil passes into breast milk. The selected product information advises interrupting breastfeeding for 24 hours after treatment; emergency use during lactation is not specifically contraindicated.
flumazenil interactions
The main concerns involve the substances being reversed and other substances taken in mixed intoxication.
Benzodiazepines
Flumazenil blocks their central sedative effects, but sedation can recur when it wears off.
Zopiclone and related benzodiazepine-receptor agonists
Their central effects may also be antagonised.
Tricyclic or other cyclic antidepressants
In mixed overdose, reversal may uncover or worsen antidepressant toxicity, including seizures and cardiac rhythm disturbances.
Common questions about flumazenil
Answers are fully visible for fast scanning and source review.
Why can someone become sleepy again after flumazenil?
Flumazenil often wears off sooner than the benzodiazepine, so sedation and breathing suppression can recur.
Can flumazenil cause seizures?
Yes. Risk is particularly important with epilepsy, prolonged benzodiazepine exposure, abrupt withdrawal or mixed ingestion involving seizure-promoting substances.
Can flumazenil be used in children?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.