Comparative efficacy and safety of lactulose plus paraffin vs polyethylene glycol in functional constipation: a randomised clinical study

Abstract

Background: Few head-to-head comparisons of the different classes of laxatives have been conducted. Objective: The objective of this work is to compare the efficacy of lactulose plus paraffin vs polyethylene glycol in the treatment of functional constipation (non-inferiority study). Methods: This randomised, parallel-group, multicentre phase 4 study recruited patients with functional constipation diagnosed according to Rome III criteria. Patients received lactulose plus paraffin or polyethylene glycol for 28 days. The primary end point was the change from baseline in the Patient Assessment of Constipation–Symptoms (PAC-SYM) score. Results: A total of 363 patients were randomised to lactulose plus paraffin (n = 179) or polyethylene glycol (n = 184). On day 28, the mean PAC-SYM score decreased significantly vs baseline with both treatments (p ' 0.001). The lower boundary of the 95% CI exceeded the pre-specified limit of −0.25, therefore establishing non-inferiority of lactulose plus paraffin vs polyethylene glycol. At least one adverse event occurred in 20 patients (11.2%) in the lactulose plus paraffin group and in 26 patients (14.2%) in the polyethylene glycol group, most of which were of mild or moderate severity and unrelated to study drugs. Conclusion: Lactulose plus paraffin may be used interchangeably with polyethylene glycol for the pharmacological treatment of functional constipation. Trial registration: EudraCT number 2015-003021-34