A Randomized Double Blind Clinical Trial Of High Volume Simethicone To Improve Visualization During Small Intestinal Capsule Endoscopy

The use of simethicone before capsule endoscopy is controversial as studies have reported inconsistent results, with some showing improved visualization only in the proximal small intestine. We hypothesized a higher volume of simethicone may produce more consistent cleansing, especially in the distal small bowel. A phase III double-blind randomized controlled trial was conducted comparing high volume (1125 mg simethicone in 750 ml water) and control volume (300 mg simethicone in 200 ml water) solutions, both at 1.5 mg/ml. The primary outcome was adequate bowel preparation, defined as a KODA score >2.25, overall and stratified by the proximal and distal half of the small bowel, read in duplicate by blinded readers. Secondary outcomes included mean KODA score, diagnostic yield, cecal intubation rate, and adverse events. All analyses were intention-to-treat. A total of 159 patients were randomized (mean (SD) age 58.7 (15.7), 54% female) and the most common indication was obscure gastrointestinal bleeding (71.7%). Compared to the control volume, high volume was not more likely to achieve adequate bowel preparation (48% vs. 50%, p=0.82) overall, for the proximal half (64% vs. 71%, p=0.40), or the distal half of the small bowel (37% vs. 36%, p=0.88). There was no difference in the mean (SD) KODA score (2.18 (0.4) vs. 2.20 (0.4), p=0.73), diagnostic yield (56% vs. 53%, p=0.71), or cecal intubation (both 95%). There was one adverse event, nausea, reported in the control group. High volume simethicone does not improve visualization during capsule endoscopy.