Crystalline Lactulose for Colonoscopy Bowel Preparation: A Pilot Study on Safety, Tolerability and Effectiveness

Abstract

Purpose: Crystalline lactulose is currently used for treatment of constipation. This pilot study was designed to assess the safety, efficacy and tolerability of crystalline lactulose as a bowel preparation regimen prior to colonoscopy. Methods: Subjects already scheduled for colonoscopy were prospectively enrolled. Subjects underwent breath testing the day before the colonoscopy (prior to taking lactulose) and repeat breath testing after finishing the bowel preparation but 1-3 hours before the procedure, in order to measure intestinal hydrogen and methane levels (which can pose an explosion risk during polypectomy). The bowel preparation consisted of 9 doses of 20 g crystalline lactulose, each mixed in 4 oz of water and taken at 30 minute intervals on the evening before the colonoscopy, together with another 64 oz of water consumed over the course of the day. During the colonoscopy, the bowel preparation quality was evaluated by the endoscopist using the validated Boston Bowel Preparation Score (0-9). Mail-back questionnaires asked subjects about adverse symptoms during the bowel preparation, and whether they preferred crystalline lactulose over previous bowel preparations with which they had experience. Results: 20 subjects were enrolled, but one had to be excluded because she misunderstood the instructions and did not take any water with her lactulose. The remaining 19 subjects had an average Boston Score of 7.7 (range 5-9), with 13 subjects having scores of 8 or 9. From a clinical standpoint, all subjects had bowel preparations judged to be “adequate” or better, and none required premature repeat colonoscopy because of suboptimal visualization. The subject with the lowest score of 5 had a history of chronic constipation. Another subject who had failed a previous polyethylene glycol (PEG) bowel preparation now had a score of 7, while two subjects whose procedures were done in the late afternoon (after 4pm) had scores of 7 and 9. All subjects had safe hydrogen and methane levels between 1-175 ppm and 2-6 ppm, respectively (explosion thresholds are estimated to be 40,000 ppm and 50,000 ppm for hydrogen and methane, respectively). All subjects subjectively reported that the crystalline lactulose was highly tolerable, and 14 subjects who had previous experience with other bowel preparations (in most cases PEG) unanimously preferred crystalline lactulose. Five subjects experienced mild nausea during the bowel preparation, but none had to slow down or stop their bowel preparation. There were no other adverse events. Conclusion: Preliminary data from this pilot study show that crystalline lactulose is safe, effective and surprisingly well tolerated. These results need to be confirmed by a larger, blinded randomized controlled study. Disclosure: Dr. Otto Lin - Grant, Cumberland Pharmaceuticals. This research was supported by an industry grant from Cumberland Pharmaceuticals.