Oral Lactulose vs. Polyethylene Glycol for Bowel Preparation in Colonoscopy: A Randomized Controlled Study

Background Colonoscopy is the method of choice to evaluate colonic mucosa and the distal ileum, allowing the diagnosis and treatment of many diseases. Appropriate bowel preparation necessitates the use of laxative medications, preferentially by oral administration. These include polyethylene glycol (PEG), sodium picosulfate, and sodium phosphate (NaP). Lactulose, a semi-synthetic derivative of lactose, undergoes fermentation, acidifying the gut environment, stimulates intestinal motility, and increases osmotic pressure within the lumen of the colon. Methods In this prospective randomized controlled study, we analyzed 40 patients who presented with symptomatic bleeding per rectum and underwent bowel preparation either with lactulose or polyethylene glycol for colonoscopy. The quality of bowel preparation and other variables like palatability, discomfort, and electrolyte levels were analyzed. Results The majority of the patients (90%) were comfortable with the taste of lactulose solution, whereas the PEG group patients (55%) were equally divided on its palatability. On lactulose consumption, 40% of patients reported nausea/vomiting and around 10% of patients complained of abdominal discomfort. Serum sodium levels showed insignificant changes from 4.33 ± 0.07 mEq/L to 4.21 ± 0.18 mEq/L while potassium also remained similar from 4.26 ± 0.03 mEq/L to 4.22 ± 0.17 mEq/L. The mean Boston Bowel Preparation Score (BBPS) in patients who received lactulose solution was 6.25 ± 0.786 and in those who received PEG solution, it was 6.35 ± 0.813 (P-value = 0.59). Conclusions Lactulose is a significantly more palatable form of bowel preparation and causes minor discomfort. It has a good bowel cleansing action comparable to PEG without causing any hemodynamic changes. It can be considered a cheaper and safe alternative for bowel preparation in colonoscopy in low-resource settings.