The effect of using simethicone with or without N-acetylcysteine before gastroscopy: A meta-analysis and systemic review

Background/Aim: To assess the efficacy and safety of simethicone with or without N-acetylcysteine (NAC) as premedications before gastroscopy. Materials and Methods: We searched EMBASE, PubMed, Cochrane library and Web of Science database for randomized clinical controlled trials regarding simethicone ± NAC as oral drinking agents before gastroscopy. Statistical software RevMan5.3 was used for statistical analysis. Results: Ten randomized clinical trials that fulfilled the inclusion criteria were further pooled into a meta-analysis, which included 5,750 patients. The rate of positive findings in simethicone plus NAC group was higher than that in water group (risk ratio [RR] =1.31, 95%CI: 1.12–1.53, P = 0.0006) with high level of evidence. There was no significant difference on the rate of positive findings when comparing simethicone with simethicone plus NAC (RR = 1.02, 95%CI: 0.90–1.16, P = 0.71) and with water (RR = 1.13, 95%CI: 0.82–1.55, P = 0.46), respectively. Simethicone plus NAC showed better total mucosal visibility score than simethicone alone (MD = −0.14 (−0.25, −0.03), P = 0.01) without obvious heterogeneity. Both simethicone plus NAC and simethicone alone offer more benefit than water. The procedure time in simethicone group was shorter than that in water group (MD = −1.23 (−1.51, −0.96), P < 0.00001). Regarding adverse events, there was no significant difference in simethicone and water group (RR = 0.45, 95%CI: 0.2–1.0, P = 0.05, I2 = 0%). Conclusions: As premedication of gastroscopy, simethicone plus NAC offers more benefit on positive findings and total mucosal visibility score.