Pharmacodynamics study of remimazolam besylate in anxious patients undergoing gastroscopy: a biased-coin design up-and-down sequential allocation trial.

BACKGROUND

This study aimed to evaluate the impact of anxiety on the pharmacodynamics of remimazolam besylate in patients undergoing gastroscopy.

METHODS

Patients undergoing gastroscopy were divided into two groups: an anxiety group (Self -rating Anxiety scale, SAS ≥ 50) and a non-anxiety group (SAS < 50). All patients received intravenous administration of 5 µg/kg alfentanil combined with remimazolam besylate. The biased coin design up-and-down sequential method (BCD-UDM) was used to determine the target doses of remimazolam besylate: the initial dose was 0.1 mg/kg, with a dose gradient of 0.01 mg/kg. If coughing, swallowing, or body movement reactions occurred within the first 2 min from the start of gastroscopy, it was considered a positive reaction, and the dose was increased for the next patient. Otherwise, it was considered a negative reaction, and the dose of remimazolam besylate for the next patient was determined according to the BCD-UDM. Discharge time from the recovery room and adverse reactions were recorded. The ED50, ED90, and their 95% confidence intervals (CI) were calculated.

RESULTS

The ED50 and ED90 of remimazolam besylate in the anxiety group were 0.175 mg/kg (95% CI, 0.140-0.240) and 0.251 mg/kg (95% CI, 0.173-0.250), respectively. In contrast, the ED50 and ED90 of remimazolam besylate in the non-anxiety group were 0.126 mg/kg (95% CI, 0.116-0.150) and 0.148 mg/kg (95% CI, 0.130-0.160), respectively. The ED90 equivalent ratio of the non-anxiety group to the anxiety group was 0.59 (95% CI, 0.468-0.710). The discharge time from the recovery room and the incidence of adverse reactions did not differ significantly between the groups.

CONCLUSIONS

When combined with 5 µg/kg alfentanil, the ED50 and ED90 of remimazolam besylate for inhibiting body movement response within two minutes of gastroscopy in anxious patients were 0.175 mg/kg and 0.251 mg/kg, respectively. Anxiety increased the requirement for remimazolam besylate in patients undergoing gastroscopy, but it did not increase the risk of prolonged discharge time or adverse effects.

TRIAL REGISTRATION: The study was registered in the Chinese Clinical Trial Registry. (ChiCTR2400086957) on July 15, 2024.