Fumazenil is an imidazobenzodiazepine derivative and a potent benzodiazepine receptor antagonist that competitively inhibits the activity at the benzodiazepine recognition site on the GABA/benzodiazepine receptor complex, thereby reversing the effects of benzodiazepine on the central nervous system. Fumazenil is used for the complete or partial reversal of the sedative effects of benzodiazepines in cases where general anesthesia has been induced and/or maintained with benzodiazepines, and where sedation has been produced with benzodiazepines for diagnostic and therapeutic procedures. Also for the management of benzodiazepine overdose as an adjunct for appropriate supportive and symptomatic measures. Flumazenil went off patent in 2008 so at present generic formulations of this drug are available.

Midazolam, previously marketed under the trade name Versed, is a medication used for anesthesia, procedural sedation, trouble sleeping, and severe agitation. Midazolam is a short-acting benzodiazepine central nervous system (CNS) depressant. Pharmacodynamic properties of midazolam and its metabolites, which are similar to those of other benzodiazepines, include sedative, anxiolytic, amnesic and hypnotic activities. Benzodiazepine pharmacologic effects appear to result from reversible interactions with the γ-amino butyric acid (GABA) benzodiazepine receptor in the CNS, the major inhibitory neurotransmitter in the central nervous system. The action of midazolam is readily reversed by the benzodiazepine receptor antagonist, flumazenil. Data from published reports of studies in pediatric patients clearly demonstrate that oral midazolam provides safe and effective sedation and anxiolysis prior to surgical procedures that require anesthesia as well as before other procedures that require sedation but may not require anesthesia. The most commonly reported effective doses range from 0.25 to 1 mg/kg in children (6 months to <16 years). The single most commonly reported effective dose is 0.5 mg/kg. Time to onset of effect is most frequently reported as 10 to 20 minutes. The effects of midazolam on the CNS are dependent on the dose administered, the route of administration, and the presence or absence of other medications.

1-Hydroxymidazolam (Alpha-hydroxy-midazolam) is pharmacologically active midazolam metabolite, which is, like the parent drug midazolam a neuronal depressant drug. There are numerous studies in which the statements concerning the contribution of 1-Hydroxymidazolam to the clinical actions of midazolam range from “almost equipotent” to “no major contributing factor”. In humans, Hydroxymidazolam is subject to further glucuronidation, followed by renal excretion. In humans, urinary recovery of 1-Hydroxymidazolam glucuronide accounted for 60 to 70% of an administered dose of [14C]midazolam. 1-Hydroxymidazolam and it’s glucuronide were found in patients with renal failure after administration of midazolam and may account for the prolonged sedation observed in those patients.