Polyethylene glycol (PEG) is tolerated well in elderly constipated patients, suggests a single blind, randomized, multicentre, parallel group comparative study published in the Journal of Nutrition, Health and Aging. This study was conducted to determine the tolerance and potential nutritional consequences of long-term repeated doses of PEG (10 to 30 g/day) in elderly patients with chronic constipation in comparison with lactulose (10-30 g/day). Subjects aged >70 years with a history of chronic constipation were enrolled and randomized to receive PEG or lactulose (10-30 g/day) for a period of months. In all, 245 patients constituted the ITT population (PEG: N = 118; lactulose group: N = 127). Following a D-xylose challenge test, the proportion of patients with abnormally low xylosaemia (suggesting malabsorption) ranged from 24.6% at baseline to 35.8% after six months in the PEG group and from 29.1% to 42.4% in the lactulose group. There were no significant between-group or within-group differences. The proportion of patients with poor nutritional status (MNA score <17) varied from 8.5% at baseline to 9.8% after 6 months in the PEG group compared to 3.9% to 5.0% in the lactulose group. There seemed to be no changes in stool fat or total or soluble stool nitrogen among the patients for whom stool analysis was performed. A significantly higher stool frequency (p <0.05) and improved stool consistency (p <0.05) was observed in the PEG group compared to the lactulose group at each monthly evaluation period.

Following 6 months of treatment with PEG, there were no clinically relevant changes in biochemical and nutritional parameters and no unanticipated treatment-related adverse events, thus highlighting the good clinical tolerance of PEG in this population of elderly constipated patients. This could be attributed to a better clinical efficacy of PEG compared to lactulose.