[The effect of polyethylene glycol in chronic constipation is not sufficiently evaluated. A systematic literature review].

Five studies compared polyethylene glycol (PEG), an osmotic laxative, with placebo. In two studies the comparison was lactulose and in one study two different doses of PEG 3350 and PEG 4000, respectively were evaluated. PEG is associated with an increase in bowel movement frequency when compared with placebo. There was inadequate evidence to establish whether PEG was superior to lactulose. Data from elderly patients are lacking and data from patients with constipation due to Parkinson's disease, multiple sclerosis or opioid therapy was only evaluated in two very small studies. Severe side-effects with PEG are rare. There are no convincing data regarding the superiority with PEG in flatulence. On the whole there is a real lack of research into treatment of the chronic constipation in adults as well as in the elderly.