title: The add-on N-acetylcysteine is more effective than dimethicone alone to eliminate mucus during narrow-band imaging endoscopy: a double-blind, randomized controlled trial.
abstract: OBJECTIVE
  Recent studies have shown that pronase can improve mucosal visibility, but this agent is not uniformly available for human use worldwide. This study aimed to assess the efficacy of N-acetylcysteine (NAC), a mucolytic agent, in improving mucus elimination as measured by decreased endoscopic water flushes during narrow-band imaging (NBI) endoscopy.
  
  
  METHODS
  A consecutive series of patients scheduled for upper gastrointestinal endoscopy at outpatient clinics were enrolled in this double-blind, randomized controlled trial. The control group drank a preparation of 100 mg dimethicone (5 ml at 20 mg/ml) plus water up to 100 ml, and the NAC group drank 300 mg NAC plus 100 mg dimethicone and water up to 100 ml. During the endoscopy, the endoscopist used as many flushes of water as deemed necessary to produce a satisfactory NBI view of the entire gastric mucosa.
  
  
  RESULTS
  In all, 177 patients with a mean age of 51 years were evaluated in this study. Significantly lesser water was used for flushing during NBI endoscopy for the NAC group than the control group; 40 ml (30-70, 0-120) versus 50 ml (30-100, 0-150) (median (interquartile range, range), p = 0.0095).
  
  
  CONCLUSIONS
  Considering the safety profile of NAC, decreasing the number of water flushes for optimal vision and unavailability of pronase in some areas, the authors suggest the use of add-on NAC to eliminate mucus during NBI endoscopy.
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology, Mackay Memorial Hospital, Taipei, Taiwan.
authors.forename: Ming-Jen
authors.initials: MJ
authors.lastname: Chen
authors.forename: Horng-Yuan
authors.initials: HY
authors.lastname: Wang
authors.forename: Chen-Wang
authors.initials: CW
authors.lastname: Chang
authors.forename: Kuang-Chun
authors.initials: KC
authors.lastname: Hu
authors.forename: Chien-Yuan
authors.initials: CY
authors.lastname: Hung
authors.forename: Chih-Jen
authors.initials: CJ
authors.lastname: Chen
authors.forename: Shou-Chuan
authors.initials: SC
authors.lastname: Shih
mesh_terms: D000111:Acetylcysteine / Q000008:administration & dosage; D000284:Administration, Oral; D004129:Dimethylpolysiloxanes / Q000008:administration & dosage; D004311:Double-Blind Method; D005100:Expectorants / Q000008:administration & dosage; D005260:Female; D005773:Gastroscopy / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D062048:Narrow Band Imaging / Q000379:methods*; D017063:Outcome Assessment, Health Care; D013274:Stomach Neoplasms / Q000175:diagnosis*
chemical_list: D004129:Dimethylpolysiloxanes; D005100:Expectorants; C501844:dimethicone; D000111:Acetylcysteine