Blood Pressure Reduction During Anesthetic Induction with Remimazolam versus Propofol in Elderly Patients: Pharmacodynamic Modeling of Remimazolam

Purpose: Remimazolam, a novel hypnotic agent, has demonstrated superior hemodynamic stability compared with propofol during general anesthesia, particularly in elderly patients. However, the dose-dependent reduction in blood pressure associated with remimazolam has not been quantitatively modeled in this population. Patients and Methods: We analyzed data from 432 patients aged ≥ 65 years who underwent elective gastrectomy as part of a randomized trial comparing remimazolam with propofol. Remimazolam was administered via zero-order infusion at 6 mg/kg/h, whereas propofol was delivered using target-controlled infusion (TCI) guided by the Schnider model. Blood pressure data were transformed into fractional changes in mean arterial pressure (MBP) relative to baseline. A modified simple logistic regression model was developed to characterize the relationship between cumulative remimazolam dose and MBP reduction, with body weight evaluated as a covariate. Results: A total of 209 patients were analyzed in each group. The modified logistic model effectively described the dose-dependent MBP reduction associated with remimazolam. Body weight was identified as a significant covariate that improved model performance. Although the remimazolam group exhibited a statistically greater MBP reduction before intubation than the propofol group (28.0 ± 9.9% vs 25.8 ± 10.1% reduction from baseline, P = 0.024), the difference was not considered clinically meaningful. Conclusion: In elderly patients undergoing general anesthesia with remimazolam, the relationship between dose and MBP reduction during induction was well characterized using a modified logistic model, with body weight as a significant covariate. TCI may represent an effective dosing strategy for maintaining hemodynamic stability during anesthetic induction. Trial Registration: This study was registered at the Clinical Research Information Service of the Korean National Institute of Health (CRIS, http://cris.nih.go.kr), with registration number KCT0006877, on December 27, 2021.