Remimazolam: its clinical pharmacology and evolving role in anesthesia and sedation practice

Remimazolam is a novel benzodiazepine anesthetic/sedative, designed as a rapidly metabolized carboxylic acid. Since its recent launch, the role of remimazolam in modern anesthesia and sedation practice is still evolving. This review aims to outline the clinical pharmacology and clinical utility of remimazolam to elucidate its potential advantages and limitations.

Remimazolam is "short-acting" but not ultra-short-acting compared with propofol based on context-sensitive decrement times. But compared to propofol, the availability of the benzodiazepine antagonist, flumazenil, is considered an advantage, particularly in certain emergency situations such as in patients with difficult airways. However, because flumazenil is shorter acting than remimazolam when remimazolam accumulates or is present in a high concentration, the reappearance of remimazolam sedation may occur after the initial reversal of anesthesia/sedation from flumazenil administration. Although it is beneficial that remimazolam causes less respiratory depression and hypotension than propofol, serious respiratory depression and hypotension can still occur. Remimazolam administration causes minimal or no pain on injection. Remimazolam is associated with less postoperative nausea and vomiting than inhaled anesthetics, but propofol is clearly superior in this regard. The anesthetic/sedative effects may be prolonged by severe hepatic impairment; remimazolam tolerance can occur in long-term benzodiazepine users.

Remimazolam may be beneficial to use in procedural sedation and general anesthesia for patients with difficult airways or hemodynamic instability. Further clinical studies with remimazolam are warranted to identify the potential benefits in other settings and patient populations.