Remimazolam Dosing for Gastroscopy: A Randomized Noninferiority Trial

BACKGROUND: Remimazolam, an ultra-short-acting benzodiazepine, may provide adequate sedation for endoscopy while causing less cardiovascular or respiratory disturbance than propofol. Although fixed-dose administration is suggested, body weight affects the volume of the central chamber and thus affects the sedation depth that can be achieved by the first dose. This study aimed to compare the efficacy and safety of different doses of remimazolam and propofol by body weight for sedation during gastroscopy. METHODS: This multicenter, randomized, single-blind, parallel-controlled noninferiority trial recruited patients from five centers between March 2021 and July 2022. A total of 1,883 patients scheduled to undergo gastroscopy were randomized to groups receiving 0.15 mg/kg remimazolam, 0.2 mg/kg remimazolam, or 1.5 mg/kg propofol. The noninferiority margin was set to 5%. The primary outcome was the success rate of sedation. Adverse events were recorded to evaluate safety. RESULTS: The sedation success rate of the 0.2 mg/kg remimazolam group was not inferior to that of the 1.5 mg/kg propofol group (98.7% vs. 99.4%; risk difference, -0.64%; 97.5% CI, -2.2 to 0.7%, meeting criteria for noninferiority). However, the sedation success rate of the 0.15 mg/kg remimazolam group was 88.5%, and that of the 1.5 mg/kg propofol group was 99.4% (risk difference, -10.8%; 97.5% CI, -14.0% to -8.0%), demonstrating inferiority. Simultaneously, the overall adverse events rate of remimazolam was lower than that of propofol, and the incidence of bradycardia, hypotension, subclinical respiratory depression, and hypoxia in the remimazolam groups was significantly lower than that in the propofol group. CONCLUSIONS: This trial established the noninferior sedation success rate of remimazolam (0.2 mg/kg but not 0.15 mg/kg) compared with propofol (1.5 mg/kg), with a superior safety profile.