Double-blind prospective randomized study comparing polyethylene glycol to lactulose for bowel preparation in colonoscopy

Background: Colonoscopy is the most frequent exam used to evaluate colonic mucosa, allowing the diagnosis and treatment of many diseases. The appropriate bowel preparation is indispensable for the realization of colonoscopy. Therefore, it is necessary the use of laxative medications, preferentially by oral administration. Aim: To compare two medications used in bowel preparation in adult patients going to ambulatory colonoscopy and to analyze the patients' profile. Methods: A double-blind prospective study with 200 patients, randomized in two groups: one that received polyethilene glycol and another that received lactulose. The patients answered to questionnaires to data compilation, as tolerance, symptoms and complications related to preparation. Besides, it was also evaluated the prepare efficacy related to the presence of fecal residue. Results: Intestinal habit alterations and abdominal pain were the main reasons to realize the exams and hypertension was the most prevalent comorbidity. Ten percent of the ones who received lactulose didn't get to finish the preparation and 50% considered the taste "bad, but tolerable". The most common subjective symptom after the medication was nausea, especially after lactulose. During the exam, most of the patients who used lactulose had a "light discomfort" and the ones who used polyethilene glycol considered the discomfort as "tolerable". The quality of the preparation was good in 75%, undependable of the medication that was used. Conclusion : Polyethilene glycol was more tolerable when compared to lactulose, without difference on the quality of the preparation.