Efficacy and safety of ciprofol versus remimazolam combined with alfentanil for sedation during outpatient colonoscopy: a randomized double-blind noninferiority trial.

INTRODUCTION: Colonoscopy often causes significant discomfort to patients. To improve patient experience, sedation-assisted colonoscopy is being increasingly adopted. This study was designed to assess the efficacy and safety of ciprofol versus remimazolam combined with alfentanil during outpatient colonoscopy. METHODS: A randomized, double-blind controlled clinical trial was performed among patients scheduled for elective outpatient colonoscopy. Patients were randomly allocated at a 1:1 ratio to two groups: the ciprofol group (Group C, 0.4 mg.kg-1 intravenously, n = 88) and the remimazolam group (Group R, 0.3 mg.kg-1 intravenously, n = 88). Intravenous alfentanil (3 μg.kg-1) was administered to all patients in conjunction with the study drug. The primary outcome was the success rate of colonoscopy. Secondary outcomes included induction time, discharge time, satisfaction levels (patients and endoscopists), and adverse events. RESULTS: In the ITT population, colonoscopy success rates were 100.0% (88/88) in Group C and 98.9% (87/88) in Group R (treatment difference [95% CI]: 0.011 [-0.024 to 0.048]). The lower bound of the two-sided 95% CI was above the prespecified noninferiority margin of -0.08, confirming the noninferiority of ciprofol relative to remimazolam. After Bonferroni correction (adjusted threshold p < 0.0028), discharge time was longer in Group C (8.5 [6.0‒12.0] vs. 7.0 [5.0‒9.0] minutes; p = 0.002). Group R showed numerically higher MAP and HR at several time points. CONCLUSIONS: This study demonstrated that intravenous ciprofol (0.4 mg.kg-1) or remimazolam (0.3 mg.kg-1), combined with alfentanil (3 μg.kg-1), provided effective sedation for outpatient colonoscopy.