Simethicone dosages with minimal normal saline solution volume to enhance mucosal visualization in upper endoscopy: a multicenter, randomized, double-blind, placebo-controlled trial

Premedication with simethicone before esophagogastroduodenoscopy improves mucosal visibility, but the appropriate dose remains unclear. This placebo-controlled trial compared 3 simethicone doses administered 15-30 min before esophagogastroduodenoscopy. In this randomized, double-blind, placebo-controlled, multicenter trial (1 June 2024-31 January 2025), 268 patients were assigned to placebo (n = 66) or simethicone (40 mg (n = 67) 80 mg (n = 67) or 160 mg (n = 68)). Each dose was diluted with normal saline solution to 2.4 ml. Mucosal visibility from the esophagus to the duodenum was assessed using validated scoring systems. The primary outcome was the total mucosal visibility score, while the secondary outcomes were procedure duration, amount of additional simethicone required, and patient satisfaction. All simethicone groups had lower total mucosal visibility scores than placebo (9.9 ± 1.4, 10.1 ± 1.7, and 9.9 ± 1.2 vs 14.2 ± 2.7; P < 0.001). No significant differences were observed among simethicone doses. Procedure durations were shorter in all simethicone arms (2.89-2.96 min) compared with placebo (3.63 min; P < 0.001). The additional simethicone administered was minimal in all simethicone groups, and patient satisfaction scores did not differ. Simethicone doses of 40, 80, and 160 mg with minimal normal saline solution improved mucosal visibility and modestly reduced procedure time compared with placebo. No dose-related differences were observed.