Daily polyethylene glycol over 6 months was effective for chronic constipation.

M e t h o d s Design: Randomized placebo-controlled trial. Allocation: Unclear allocation concealment.* Blinding: Blinded (unclear which groups were blinded).* Follow-up period: 6 months. Setting: 50 centers in the United States. Patients: 306 patients with chronic constipation over the past 3 months (< 3 satisfactory stools per wk without laxative use and ≥ 1 of the following Rome criteria: straining, lumpy or hard stools, or sensation of incomplete evacuation in > 25% of defecations) and during a 14-day observation period (< 3 satisfactory bowel movements per wk). Exclusion criteria were prior or current treatment with or sensitivity to study medication; use of medications affecting bowel function; the irritable bowel syndrome; pregnancy or lactation; past gastrointestinal (GI) surgery; known or suspected GI obstruction; ileus; ascites; or chronic bowel, liver, or cardiopulmonary disorders. Intervention: PEG, 17 g (n = 204), or placebo (n = 100) to be mixed in 8 oz of juice or other beverage and taken daily. Outcomes: Overall treatment success (≥ 50% of treatment weeks with ≥ 3 satisfactory stools, no use of rescue laxatives, and ≤ 1 of the following in > 25% of defecations: straining, lumpy or hard stools, or sensation of incomplete evacuation). Secondary outcomes included “super efficacy,” defined as 1 week with no constipation symptoms (Rome criteria) and no use of rescue laxatives; and adverse events. Patient follow-up: 99% (mean age 53 y, 85% women) were included in the intention-to-treat analysis. 170 patients completed all 6 months of the study.