Split-dose oral lactulose vs split-dose high-volume polyethylene glycol as a bowel preparation in outpatient colonoscopies (LACPEG): a single-blind, randomized, single-center, clinical trial

Aims Lactulose (LAC), has been studied for bowel preparation for colonoscopies and has been validated for its safety and efficacy. It has shown better preparation scores compared to polyethylene glycol (PEG), as well as higher lesion detection rates, better tolerance due to the smaller volume required, better taste, and fewer adverse effects [1] [2]. To evaluate the quality of bowel preparation using the Boston bowel preparation scale (BBPS)comparing split-dose LAC versus split-dose high-volume PEG. In addition, the adenoma detection rate will be determined, the success rate of cecal intubation will be estimated, as well as the taste of each preparation and associated adverse effects.

Methods Preliminary report of a Randomized, single-blinded clinical trial conducted in a referral center in Mexico City, from July to October 2024. Patients scheduled on an outpatient basis for colonoscopies for colorectal cancer>45 years and<75 years screening were included and randomized in a 1:1 ratio to one of the following two groups: Group 1 (30 patients): LAC 125 ml (10 g/15 ml) in 600 ml of water from 21 to 22 hrs the night prior to the study, and the same dose from 5 to 6 am on the day of the study. Group 2 (30 patients): PEG 2 sachets of 109.6 grams each dissolved in 2 liters of water from 20 to 22 hrs the night prior to the study, and the same dose from 4 to 6 am on the day of the study. Analysis of the data includes descriptive statistics and to evaluate the difference between groups, Mann Whitney U, Chi-square or Student's t test was used as appropriate. Statistical analysis was performed with SPSS version 20.0. Taste rating of the preparation on a scale of 0 to 10 (0 unpleasant and 10 pleasant).

Results 55% of the participants were women, mean age of 60.2±8.2 years. There were no baseline differences among the groups regarding factors related to slow bowel transit (medications and concurrent illness). Bowel preparation was adequate in both groups, with no significant differences in the total BBPS (8.5 (7.7-9) and 9(8-9), p=0.610), scores between LAC and PEG groups, respectively. Cecal intubation was achieved in all the participants, and the adenoma detection rate was 36.6% in both groups. Palatability and willingness to repeat the bowel preparation was better in LAC than in PEG (p<0.001 and p=0.01, respectively). The most frequent adverse effect associated with both preparations was mild abdominal distention.

Conclusions In this study, LAC was not inferior to PEG in terms of bowel cleansing as measured by the BBPS, adenoma detection and cecal cannulation, similar adverse effects have been reported, however, lactulose had a better taste and more patients would repeat the preparation. These results reinforce the effectiveness of lactulose for outpatient colonoscopies and we propose to standardize the dose used for new studies.

Publication History

Article published online:
27 March 2025

• References

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• 2 Ramos JA, Carvalho D, Arantes VN.. Novel regimen for colonoscopy bowel preparation with oral lactulose: a prospective comparative study Clin Endosc. 2024.