Rapid Communication
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World J Gastroenterol. Jan 21, 2007; 13(3): 444-447
Published online Jan 21, 2007. doi: 10.3748/wjg.v13.i3.444
Premedication with pronase or N-acetylcysteine improves visibility during gastroendoscopy: An endoscopist-blinded, prospective, randomized study
Chun-Chao Chang, Sheng-Hsuan Chen, Chih-Ping Lin, Ching-Ruey Hsieh, Horng-Yuan Lou, Fat-Moon Suk, Shiann Pan, Ming-Shun Wu, Jun-Nan Chen, Yung-Fa Chen
Chun-Chao Chang, Sheng-Hsuan Chen, Ching-Ruey Hsieh, Horng-Yuan Lou, Fat-Moon Suk, Shiann Pan, Division of Gastroenterology, Department of Internal Medicine, Taipei Medical University Hospital; Digestive Disease Research Center, Taipei Medical University; Taipei, Taiwan, China
Ming-Shun Wu, Jun-Nan Chen, Yung-Fa Chen, Taipei Medical University-Municipal Wan-Fang Hospital, Taipei, Taiwan, China
Chih-Ping Lin, Department of Internal Medicine, Min-Sheng General Hospital, Taoyuan, Taiwan, China
Author contributions: All authors contributed equally to the work.
Supported by a grant of TMU93-AE1-B-07 and 93 MSH-TMU-09 of Taipei Medical University
Correspondence to: Dr. Chun-Chao Chang, Division of Gastroenterology, Department of Internal Medicine, Taipei Medical University Hospital, 252 Wu-Hsing Street, Taipei 110, Taiwan, China. chunchao@tmu.edu.tw
Telephone: +886-2-27372181-3903 Fax: +886-2-27363051
Received: March 13, 2006
Revised: June 20, 2006
Accepted: December 11, 2006
Published online: January 21, 2007
Abstract

AIM: To assess the efficacy of premedicaton with pronase or N-acetylcysteine (NAC) at 20 min before upper gastrointestinal (UGI) endoscopy and to determine whether pronase or NAC pretreatment influences the reliability of the rapid urease test.

METHODS: A total of 146 patients were prospectively and randomly assigned into the study groups according to different premedications before endoscopy. One endoscopist assessed mucosal visibility (MV) with scores ranged from 1 to 4 at four sites in the stomach. The sum of the MV scores from these four locations was defined as the total mucosal visibility (TMV) score. Identification of H pylori was performed using CLO test, histology, and serology.

RESULTS: The Group with pronase premedication had a significantly lower TMV score than did the groups with gascon and gascon water (p < 0.001 and p < 0.01, respectively). The group with NAC had a significantly lower TMV score than the group with gascon (p < 0.01) and a trend of a lower MV score than the group with gascon water (p = 0.06). The TMV score did not significantly differ between the group with pronase and the group with NAC (p = 0.39 and p = 0.14, respectively). The sensitivity and specificity of the CLO test were 92.5% and 93.9%, respectively, in groups premedicated with pronase and NAC together.

CONCLUSION: Premedication with pronase or NAC at 20 min before UGI endoscopy improves the mucosal visibility of the stomach. Neither pronase nor NAC produces any obvious interference with the CLO test for the identification of H pylori infection.

Keywords: Pronase; N-acetylcysteine; H pylori; Gastrointestinal endoscopy