Attar, A., Lemann, M., Ferguson, A., Halphen, M., Boutron, M.C., Flourie, B., . . . Barthet, M. (1999). Comparison of a low dose polyethylene glycol electrolyte solution with lactulose for treatment of chronic constipation. Gut, 44, 226–230.
In part A, patients were randomized to receive either PEG plus electrolytes (PEG+E) (n = 60) or lactulose (n = 55) for one month. In part B, 65 patients continued on the treatment for another two months. Patients received PEG+E, irrespective of the laxative they received at the start of part A.
PEG 3350 is an osmotic laxative that opposes the colon’s normal drying action on the feces. The increasing fecal bulk stretches the circular muscle fibers in the bowel wall and triggers myogenic peristalsis. PEG+E provides electrolyte depletion and dehydration that can occur with other laxatives.
Lactulose is metabolized to lactic acid by bacteria in the colon. Those bacteria exert a local osmotic effect, drawing water and electrolytes into the colon from the surrounding tissues to bulk feces.
This was a single-blind, randomized, multicenter study.
The efficacy of PEG+E was evaluated by
Use of PEG+E instead of lactulose doubled the percentage of patients successfully treated at three months. PEG+E was found to be a superior treatment compared to lactulose to treat idiopathic constipation. The study was well designed.