In elderly people (aged 65-89 years) undergoing gastrointestinal (GI) endoscopy, the combination of propofol with esketamine minimized the propofol median effective concentration (EC₅₀) during GI endoscopy versus administration of propofol without esketamine, according to a study published in The British Journal of Clinical Pharmacology. Researchers undertook a randomized controlled trial for determining the EC₅₀ of propofol with varying doses of esketamine during GI endoscopy.

Overall, 90 participants were segregated into three arms: SK0 (control) arm (0 mg/kg esketamine), SK0.25 arm (0.25 mg/kg esketamine), and SK0.5 arm (0.5 mg/kg esketamine). Using plasma target-controlled infusion of propofol with varying bolus doses of esketamine, anaesthesia was attained.

With the aid of the up-and-down method of Dixon, determination of EC₅₀ of propofol for GI endoscopy was done. The adjacent concentration gradient was 0.5 μg/mL, while the initial plasma target concentration was 2.5 μg/mL. Estimation of cardiovascular variables was also done. Table 1 denotes propofol EC₅₀ for GI endoscopy and the average percent alteration from baseline mean arterial pressure in the study groups.

Escalating doses of esketamine with propofol are unlikely to elicit hypotension with a shorter recovery time, concluded the study authors.