Medicines & Supplements A to Z > Flumazenil


Last updated on 13/07/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions  |   Tips  |   Where To Buy  

GENERIC NAME: Flumazenil



DRUG CLASS: Antidotes

SUB CLASS: Benzodiazepine antagonists

USED FOR: Benzodiazepine overdose, Reversal of benzodiazepine activity

AVAILABLE DOSAGE FORMS: 0.5mg/5ml (injections)

What is Flumazenil for?

Flumazenil belongs to a class of medications called benzodiazepine antagonists. It works by counteracting the effects of benzodiazepines, to treat its overdose and reverse its activity in general anesthesia or conscious sedation.

How to use it?

Flumazenil is administered intravenously. 

For benzodiazepine overdose:
Initiate 0.2 mg over 30 seconds. If the desired level of consciousness is not obtained 30 seconds after the dose, 0.3 mg can be given over 30 seconds. Then, repeat 0.5 mg over 30 seconds at 1-minute intervals. Most patients with a benzodiazepine overdose will respond to a cumulative dose of 1-3 mg.

For benzodiazepine reversal in conscious sedation or general anesthesia:
Initiate 0.2 mg over 15 seconds. If the desired level of consciousness is not obtained 45 seconds after the dose, 0.2 mg can be given at 1-minute intervals as needed up to 4 additional doses. The dosage should be individualized based on the patient’s response, with most patients responding to doses of 0.6-1 mg.

What are the side effects of Flumazenil?

Common side effects of Flumazenil include vomiting, palpitation, dizziness, dry mouth, injection site pain and swelling, and vertigo.

Who should not take Flumazenil?

– People who are allergic to Flumazenil, benzodiazepines, or any component of the formulation.
– Patients given benzodiazepines for control of potentially life-threatening conditions, such as control of intracranial pressure or status epilepticus.
– Patients who are showing signs of cyclic-antidepressant overdose.

Pharmacist Tips:

– Do not drink alcohol and take non-prescription drugs during the first 24 hours after flumazenil administration or if the effects of benzodiazepine persist.
– Do not drive or operate machinery until at least 24 hours after discharge and until it has been determined that no residual sedative effects of benzodiazepine remain.

Common dosing schedule:

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Flumazenil may interact with:
Tricyclic antidepressants, e.g. Amitriptyline, Nortriptyline

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Flumazenil in Hong Kong?

In Hong Kong, Flumazenil is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at

Need more information?

For detailed information about the use of Flumazenil in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.