Cochrane Review: Lactulose versus Polyethylene Glycol for Chronic Constipation
Authors: Lee‐Robichaud Heather , Thomas Kathryn , Morgan Jenna , Nelson Richard L 
Published: April 2011

AbstractBackgroundConstipation is a common clinical problem. Lactulose and Polyethylene Glycol (PEG) are both commonly used osmotic laxatives that have been shown to be effective and safe treatments for chronic constipation. However, there is no definitive data as to which provides the best treatment.ObjectivesTo identify and review all relevant data in order to determine whether Lactulose or Polyethylene Glycol is more effective at treating chronic constipation and faecal impaction.Search strategyWe searched the MEDLINE, EMBASE and CINAHL databases, and the Cochrane Central Register of Controlled Trials for all randomised controlled trials (RCTs) comparing the use of lactulose and polyethylene glycol in the management of faecal impaction and chronic constipation.Selection criteriaStudies were included if they were randomised controlled trials which compared lactulose with polyethylene glycol in the management of chronic constipation.Data collection and analysisData on study methods, participants, interventions used and outcomes measured was extracted from each study. Data was entered into the Cochrane Review Manager software (RevMan 5.0) and analysed using Cochrane MetaView.Main resultsIn the present meta‐analysis, we considered for the first time all ten randomised controlled trials so far performed. The ten trials enrolled a total of 868 participants and were conducted between 1997 and 2007. The trials were conducted in six different countries. Participant age ranged from 3 months to 70 years. Adults only were recruited for 4 studies. Five trials reported stool frequency per week. Singularly taken, all showed that PEG resulted in a higher stool frequency per week when compared with Lactulose. Two trials reported form of stool on the Bristol Stool Scale, both studies reported a higher Bristol Stool Score when using PEG compared with lactulose (softer stool). Three trials reported relief of abdominal pain. Two favoured PEG in this outcome; one found Lactulose and PEG to be comparable in this outcome. Three trials reported on use of additional products, all favoured PEG as requiring less use of additional products.Authors' conclusionsThe findings of our work indicate that Polyethylene glycol is better than lactulose in outcomes of stool frequency per week, form of stool, relief of abdominal pain and the need for additional products. On subgroup analysis, this is seen in both adults and children, except for relief of abdominal pain. Polyethylene Glycol should be used in preference to Lactulose in the treatment of Chronic Constipation.Plain Language SummaryPolyethylene Glycol should be used in preference to Lactulose in the treatment of Chronic Constipation.Constipation is a common clinical problem, encompassing much more than reduced stool frequency. In this review we compared two commonly used osmotic laxatives, Lactulose and Polyethylene Glycol (PEG). The findings of our work indicate that PEG is better than lactulose in outcomes of stool frequency per week, form of stool, relief of abdominal pain and the need for additional products. This is seen in both adults and children. Only exception is for relief of abdominal pain, where PEG is better than lactulose in children, but not in adults (no difference is seen). We conclude that Polyethylene Glycol should be used in preference to Lactulose in the treatment of Chronic Constipation.