Comparison of the efficacy and safety of etomidate and remimazolam in elderly patients for colonoscopy: a randomized clinical trial
Abstract
Background & objective: Remimazolam, a rapidly acting benzodiazepine, has demonstrated sedative efficacy comparable to propofol during endoscopic procedures. However, limited evidence exists comparing remimazolam with etomidate. This research aimed to evaluate the safety and efficacy of etomidate and remimazolam in older adults receiving colonoscopy.
Methodology: A total of 130 elderly patients (≥65 years) between June 2023 and August 2023 at Dazhou Central Hospital, categorized as ASA grades II-III with a body mass index of 18-30 kg/m2, underwent randomization to receive either remimazolam-remifentanil (RR group) and etomidate-remifentanil (ER group) sedation. All patients received remifentanil 0.5 μg/kg for analgesia. An initial dose of 0.1 mg/kg remimazolam was administered to the RR group, with 0.05 mg/kg supplemental doses provided as necessary. The ER group received etomidate 0.1 mg/kg with similar supplemental dosing. Sedation was maintained with a Modified Observer’s Assessment of Alertness/Sedation (MOAA/S) score of ≤1 and absence of body movement. Key parameters collected included sedation onset time (MOAA/S score≤1), number of supplemental doses after successful induction, mean arterial pressure, oxygen saturation, heart rate, body movement, awakening time, discharge time, postoperative nausea and vomiting (PONV), and dizziness. The primary endpoints were sedation success rate, time to MOAA/S≤1, awakening time, and discharge time. Secondary endpoints included the rate and magnitude of adverse effects.
Results: Of the 130 enrolled, 118 patients completed the study. Both groups achieved a 100% sedation success rate. The time to achieve MOAA/S≤1 was significantly longer in RR group than in ER group (68.7 ± 11.6 vs. 48.5 ± 4.9 seconds, P < 0.001). Awakening time and discharge time were also longer in RR group than in ER group (17.5 ± 3.3 vs. 11.09 ± 2.8 min, P < 0.001; 23.1 ± 4.4 vs. 19.8 ± 4.8 min, both P < 0.001). The RR group required more supplemental doses compared to the ER group throughout the procedure (11/16/26/4/3 vs. 23/23/9/2/1, P < 0.001). However, the incidence of PONV was remarkably lower in RR group than in ER group (0 vs. 5, P < 0.05). Hemodynamic and respiratory parameters remained stable in both groups.
Conclusions: Remimazolam provides comparable sedation efficacy to etomidate in elderly colonoscopy patients, with a lower PONV rate. Despite longer awakening/discharge times and more supplemental doses, remimazolam is a favorable alternative sedative for this cohort.
Trial registration: Chinese Clinical Trial Registry (ChiCTR2300071790), registered 25/05/2023.
Keywords: Remimazolam, Etomidate, Remifentanil, Colonoscopy, Sedation, Elderly
Citation: Comparison of the efficacy and safety of etomidate and remimazolam in elderly patients for colonoscopy: a randomized clinical trial. Anaesth. pain intensive care. 2026;30(4):498-505. DOI: 10.35975/apic.v30i4.3215
Received: March 16, 2026; Reviewer: March 17, 2026; Accepted: March 18, 2026
