|Trade names||Anexate, Lanexat, Mazicon, Romazicon|
|Other names||Flumazepil, Ro 15-1788, ethyl 8-fluoro- 5,6-dihydro- 5-methyl- 6-oxo- 4H- imidazo [1,5-a] [1,4] benzodiazepine- 3-carboxylate|
|Main uses||Reverse effects of benzodiazepines|
|Side effects||Sweating, blurry vision, headache, dizziness, seizures|
|Onset of action||Within 2 min|
|Duration of action||40 to 90 min|
|Typical dose||0.2 mg|
|Elimination half-life||7–15 min (initial) |
20–30 min (brain)
40–80 min (terminal)
|Excretion||Urine 90–95% |
|Chemical and physical data|
|Molar mass||303.293 g·mol−1|
|3D model (JSmol)|
Flumazenil, sold under the brand name Anexate, is a medication used to reverse the effects of benzodiazepines. Routine use is not recommended in those with a decreased level of consciousness. It is given by injection into a vein. Effects begin within 2 minutes and may last for up to 90 minutes.
Common side effects include sweating, blurry vision, headache, and dizziness. Other side effects may include seizures and benzodiazepine withdrawal, especially in people with benzodiazepine dependence. Panic attacks may also occur. Safety in pregnancy is unclear. It works by blocking benzodiazepines at the GABA receptor.
Flumazenil was characterized in 1981, and approved for medical use in the United States in 1991. It is available as a generic medication. In the United Kingdom 0.5 mg cost the NHS about £13 as of 2021. This amount in the United States is about 10 USD.
It has been used as an antidote in the treatment of benzodiazepine overdoses. There are many complications that must be taken into consideration when used in the acute care setting. These include lowered seizure threshold, agitation, and anxiousness.
Flumazenil's short half-life may require multiple doses. Because of the potential risks of withdrawal symptoms and the drug's short half-life, people must be carefully monitorered to prevent recurrence of overdose symptoms or side effects.
The onset of action is rapid, and effects are usually seen within one to two minutes. The peak effect is seen at six to ten minutes. The recommended dose for adults is 200 μg every 1–2 minutes until the effect is seen, up to a maximum of 3 mg per hour. It is available as a clear, colourless solution for intravenous injection, containing 500 μg in 5 mL.
Flumazenil, an imidazobenzodiazepine derivative, antagonizes the actions of benzodiazepines on the central nervous system. Flumazenil competitively inhibits the activity at the benzodiazepine recognition site on the GABA/benzodiazepine receptor complex. It also exhibits weak partial agonism of GABAA receptor complexes that contain α6-type monomers; the clinical relevance of this is unknown.
Flumazenil does not antagonize all of the central nervous system effects of drugs affecting GABA-ergic neurons by means other than the benzodiazepine receptor (including ethanol, barbiturates, and most anesthetics) and does not reverse the effects of opioids. It will however antagonize the action of non-benzodiazepine z-drugs, such as zolpidem and zopiclone, because they act via the benzodiazepine site of the GABA receptor - it has been used to successfully treat z-drug overdose.
It is metabolised by the liver to inactive compounds which are excreted in the urine.
Intravenous flumazenil has been shown to antagonize sedation, impairment of recall, psychomotor impairment and ventilatory depression produced by benzodiazepines in healthy human volunteers.
The duration and degree of reversal of sedative benzodiazepine effects are related to the dose and plasma concentrations of flumazenil.
Society and culture
Flumazenil is sold under a wide variety of brand names worldwide like Anexate, Lanexat, Mazicon, Romazicon. In India it is manufactured by Roche Bangladesh Pharmaceuticals and USAN Pharmaceuticals.
Radiolabeled with the radioactive isotope carbon-11, flumazenil may be used as a radioligand in neuroimaging with positron emission tomography to visualize the distribution of GABAA receptors in the human brain.
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