Polyethylene glycol (PEG) 3350, a non-absorbable, non-metabolized osmotic agent, is often used in lavage solutions for gut cleansing.

A recent multicenter, randomized, comparative trial investigated the efficacy of PEG and lactulose in chronic constipation.

The study included 115 patients with chronic constipation who initially received two sachets containing either PEG (13 g/sachet) or lactulose (10 g/sachet) and were allowed to change the dose to one or three sachets/day, depending on response.

The findings were as follows-

• Ninety-nine patients completed the trial.
• After four weeks, patients in the PEG group (n=50) experienced a higher number of stools and a lower median daily score for straining at stool than those in the lactulose group (n=49).
• The PEG group showed more significant overall improvement.
• Both the groups showed identical Clinical tolerance, but the PEG group reported less flatus.
• The PEG group experienced a higher mean number of liquid stools. However, this difference remained significant only for the first two weeks.
• None of the groups showed any serious adverse events or changes in laboratory tests.
• At the end of the study, the PEG group patients had utilized 1.6 (0.7)sachets/day, while the lactulose group patients had utilized 2.1 (0.7)/day.
• Sixty-one patients completed a further two months of an open study of one to three sachets of PEG daily; without any loss of efficacy or serious toxicity.

This study proves that Low dose PEG 3350 is more effective and better tolerated than lactulose.

Source: Attar A, Lémann M, Ferguson A, Halphen M, et al. Gut. 1999 Feb;44(2):226-30. doi: 10.1136/gut.44.2.226.