Objective To investigate the median effective dose (ED₅₀) and 95% effective dose (ED₉₅) of ciprofol in combination with butorphanol for painless gastroscopy in elderly patients.

Methods A total of 27 elderly patients with selective gastroscopy were conducted with intravenous induction of 5 μg/kg butorphanol for at least 30 seconds, and 3 minutes later, they were administered intravenously with ciprofol for at least 30 seconds; gastroscopy was performed when the eyelash reflex disappeared or the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) score was less than one point. The initial dose of ciprofol was set as 0.2 mg/kg, and the modified sequential allocation method was used; if there was a positive response during the insertion of the gastroscope, the dose for the next patient would increase by one level, and vice versa, the dose would decrease by one level, with an adjacent dose concentration gradient of 0.05 mg/kg. A positive response to gastroscope insertion was defined as coughing, swallowing, or limb movements when the gastroscope entered the throat. The study was terminated after 7 reversals in ciprofol dose adjustments. ED₅₀, ED₉₅, and corresponding 95% confidence intervals (95%CI) of ciprofol combined with butorphanol for painless gastroscopy were calculated.

Results When combined with butorphanol, the ED₅₀ of ciprofol for painless gastroscopy in elderly patients was 0.253 mg/kg (95%CI, 0.219 to 0.290), and the ED₉₅ was 0.328 mg/kg (95%CI, 0.290 to 0.521).

Conclusion When combined with butorphanol, the ED₅₀ of ciprofol for painless gastroscopy in elderly patients is 0.253 mg/kg, and the ED₉₅ is 0.328 mg/kg.