Effectiveness of premedication with pronase for improving visibility during gastroendoscopy: a randomized controlled trial

Background: Minute early gastric cancers can be removed with endoscopic mucosal resection techniques. However, early detection of these minute cancers with endoscopy is still difficult. For this purpose, use of a dye is helpful. To increase visibility further, gastric mucus should be removed before endoscopic examination. In this study, the effectiveness of premedication with pronase for improving visibility during gastroendoscopy was investigated. Methods: From January through July 1996, outpatients scheduled for gastroendoscopy were randomly assigned to oral premedication with the antifoam agent dimethylpolysiloxane alone (n = 34), with dimethylpolysiloxane plus sodium bicarbonate (n = 32), or with dimethylpolysiloxane, sodium bicarbonate, and pronase (n = 34). All were given about 10 minutes before the start of endoscopy. After inserting the endoscope, the endoscopist gave visibility scores at conventional endoscopy and after methylene blue spraying. Results: Premedication with pronase significantly improved visibility before and after methylene blue spraying as compared with the two other groups pretreated without pronase. Pronase also significantly shortened the times for chromoendoscopic examination. Pronase had no significant effect on the culture of Helicobacter pylori. Conclusion: Premedication with pronase improved endoscopic visualization during conventional endoscopy and chromoendoscopy. Its routine use at gastroendoscopy is therefore recommended. (Gastrointest Endosc 1998; 47:382-7.)