DiPalma, J.A., Cleveland, M.V., McGowan, J., & Herrera, J.L. (2006). An open-labeled study of chronic polyethylene glycol laxative use in chronic constipation. Alimentary Pharmacology and Therapeutics, 25, 703–708.

To extend the safety data of polyethylene glycol used for chronic treatment of chronic constipation.

Polyethylene glycol laxative was administered as a single daily dose of 17 g for 12 months.

• The study reported on a sample of 311 patients with chronic constipation.
• 117 patients were aged 65 years and older.
• 184 patients completed all 12 months of treatment.
• Study participants who met defined criteria for chronic constipation were enrolled.

• Multicenter
• 50 centers in the United States

This was a randomized, open-label, single-treatment study.

• Patients returned to their study centers after 2, 4, 6, 9, and 12 months of treatment; blood and urine samples were collected, and adverse events were reviewed.
• At each visit, patients were queried for Rome constipation criteria and they rated their overall improvement using a global efficacy scale.

• No clinically significant changes were found in hematology or blood chemistry, particularly electrolytes, for the study population as a whole or the older adult group.
• With respect to the global efficacy assessment, depending on the month of observation, 80% to 88% of enrolled patients and 84% to 94% of older adults were treated successfully. Similar results were obtained from secondary efficacy measures that assessed individual Rome constipation criteria at each visit.
• The response to treatment was durable over time.
• Over the one-year course of study representing 218 patient-years at the labeled dose, medication-associated adverse effects were gastrointestinal complaints of diarrhea, loose stool, flatulence, and nausea. The effects were generally mild or moderate in severity.

Polyethylene glycol laxative is safe and effective for treating constipation in adult and older adult patients for periods up to 12 months, with no evidence of tachyphylaxis.

• None were identified in the discussion of the results.
• This study was not related to cancer or to opioid-induced constipation.