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Flumazenil (also known as flumazepil, code name Ro 15-1788) is a GABAA receptor antagonist primarily available by injection only, and the only GABAA receptor antagonist on the market today. It was first introduced in 1987 by Hoffmann-La Roche under the trade name Anexate, but only approved by the FDA on December 20, 1991. Flumazenil went off patent in 2008 so at present generic formulations of this drug are available. Intravenous flumazenil is primarily used to treat benzodiazepine overdoses and to help reverse anesthesia. Administration of flumazenil by sublingual lozenge and topical cream has also been tested.〔http://clinicaltrials.gov/show/NCT01183312〕 ==Medical uses== Flumazenil is of benefit in patients who become excessively drowsy after benzodiazepines are used for either diagnostic or therapeutic procedures. It has been used as an antidote in the treatment of benzodiazepine overdoses.〔 It reverses the effects of benzodiazepines by competitive inhibition at the benzodiazepine binding site on the GABAA receptor. There are many complications that must be taken into consideration when used in the acute care setting.〔 Flumazenil's short half-life requires multiple doses and careful patient monitoring to prevent recurrence of overdose symptoms. It is also sometimes used to reverse the effects of benzodiazepines after surgery in a manner similar to naloxone's application to reverse the effect of opiates and opioids following surgery. This requires careful monitoring by an anesthesiologist due to potential side effects and serious risks associated with both over-administering flumazenil and the removal of patient life-support and monitoring equipment before the benzodiazepines have worn off (due to flumazenil masking their continued effect). Flumazenil has been effectively used to treat overdoses of non-benzodiazepine hypnotics, such as zolpidem, zaleplon and zopiclone. It may also be effective in reducing excessive daytime sleepiness while improving vigilance in primary hypersomnias, such as idiopathic hypersomnia. It has also been used in hepatic encephalopathy, though results have been mixed. The onset of action is rapid and usually effects are 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, 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. Many benzodiazepines (including midazolam) have longer half-lives than flumazenil. Therefore, repeat doses of flumazenil may be required to prevent recurrent symptoms of overdosage once the initial dose of flumazenil wears off. It is hepatically metabolised to inactive compounds which are excreted in the urine. Subjects who are physically dependent on benzodiazepines may suffer benzodiazepine withdrawal symptoms, including seizure, upon rapid administration of flumazenil. It is not recommended for routine use in those with a decreased level of consciousness. Considering its use as an antidote in benzodiazepine overdoses, orders for flumazenil may serve as a clue or trigger to initiate a more detailed prescription audit in the search for adverse drug events and clinically significant drug interactions related to the use of benzodiazepines. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Flumazenil」の詳細全文を読む スポンサード リンク
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