Efficacy of premedication with activated Dimethicone or N-acetylcysteine in improving visibility during upper endoscopy

World J Gastroenterol. 2011 Oct 7;17(37):4213-7. doi: 10.3748/wjg.v17.i37.4213.


Aim: To assess the efficacy of N-acetylcysteine (NAC) and activated Dimethicone in improving endoscopic mucosal visibility.

Methods: A total of 148 patients were randomly allocated into four groups to receive one of the following premedications: group A: 100 mL water alone; group B: activated Dimethicone plus water (up to 100 mL); group C: NAC plus water (up to 100 mL); and group D: activated Dimethicone and NAC plus water (up to 100 mL). A single endoscopist blinded to the patients group assessed the gastric mucosal visibility scores (range 1-4) at four sites. The sum of the scores from the four sites was considered as the total mucosal visibility score (TMVS).

Results: The patients in group B showed a significantly lower TMVS than those of groups A and C (P < 0.001). The TMVS in patients of group D was significantly lower than that of groups A and C (P < 0.001). The TMVS did not significantly differ between groups B and D (P > 0.05). The difference between TMVS of groups C and A was not significant (P > 0.05).

Conclusion: Premedication with activated Dimethicone 20 min prior to the upper endoscopy leads to the best visibility. NAC does not improve visualization by itself.

Keywords: Dimethicone; N-acetylcysteine; Simethicone; Upper endoscopy.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Acetylcysteine*
  • Adult
  • Aged
  • Dimethylpolysiloxanes*
  • Double-Blind Method
  • Female
  • Gastroscopy / methods*
  • Humans
  • Male
  • Middle Aged
  • Placebos
  • Premedication*


  • Dimethylpolysiloxanes
  • Placebos
  • dimethicone 20
  • Acetylcysteine