Remimazolam besilate, a benzodiazepine, has been approved for general anesthesia!!

Excerpt

In January 2020, remimazolam besilate, a novel benzodiazepine, was approved as a general anesthetic in Japan firstly in the world. A novel anesthetic, remimazolam, would be desired to have advantages beyond existing anesthetics such as inhalation anesthetics, propofol, and midazolam. Inhalation anesthetics might trigger malignant hyperthermia, and is a risk for postoperative nausea and vomiting (PONV), while a benzodiazepine, midazolam, is not a trigger for malignant hyperthermia and has an advantage to reduce PONV [1]. Remimazolam induced mild and transient nausea after bolus but not seems to have high risk of PONV [2]. An inhalation anesthetic but not an intravenous anesthetic including remimazolam pollutes environmental air including in the operation room [3]. Large dose and longer infusion of propofol is a risk of propofol infusion syndrome in both children and adults [4]. Injection pain of propofol is also a clear disadvantage although the use of lidocaine or opioid may reduce the injection pain [5, 6]. Remimazolam had no notable injection pain in a phase I clinical trial [2]. Midazolam is sometimes used for general anesthesia but not often, maybe due to long-acting property than propofol and inhalation anesthetics and large interindividual variability [7]. Prolonged effect of an active metabolite of midazolam may cause a difficulty to use midazolam [8], while remimazolam is metabolized by tissue esterases to an inactive metabolite [9]. Context-sensitive half-time (CSHT) estimated from a pharmacokinetic/pharmacodynamic analysis has revealed that the off-set of the remimazolam after the stop of its infusion is faster than that of the midazolam. For instance, when comparing half-time after 3 h constant rate infusion, the half-time of remimazolam is approximately one-fifth shorter than that of midazolam [10]. Note that the researchers calculated CSHT in untypical way (the detail is discussed below). On the above-mentioned beneficial properties, remimazolam has a potential to be a principal intravenous anesthetic for general anesthesia. …