Polyethylene glycol 3350 plus electrolytes for chronic constipation: a 2-week, randomized, double-blind, placebo-controlled study with a 52-week open-label extension.

Background: Although polyethylene glycol 3350 plus electrolytes (PEG3350 + E) is the most widely used osmotic laxative in Europe, prospective data on its long-term (over 6 months) safety and efficacy are not available to date.

Methods: Japanese patients with chronic constipation were randomized to receive PEG3350 + E or placebo for 2 weeks orally. Following this, the patients received PEG3350 + E in the 52-week extension study. The starting dose was 13.7 g/day dissolved in 125 mL of water, and dose titration was allowed (upper limit 41.1 g/day) according to the patient's bowel condition. The primary efficacy endpoint was the change from baseline in frequency of spontaneous bowel movements (SBMs) at week 2 in the double-blind study. Secondary endpoints and adverse events were assessed. Safety and efficacy were also assessed in the extension study.

Results: Among 204 patients who provided informed consent, 156 were randomized and included in the full analysis. The frequency of SBMs was significantly higher with PEG3350 + E [least squares mean (LSM) 4.3, 95% confidence interval (CI) 3.6-4.9] compared with placebo (LSM 1.6, 95% CI 1.2-2.1; P < 0.0001). A total of 153 patients entered the extension study; PEG3350 + E led to a sustained improvement in bowel function. The common adverse drug reactions during the entire study period were mild gastrointestinal disorders (abdominal pain 4.5%, diarrhea 3.8%, nausea 3.2%, abdominal distension 2.6%).

Conclusions: Treatment with PEG3350 + E resolved constipation in the short term, was well tolerated, and led to sustained improvement in bowel function in the long-term treatment of Japanese patients with chronic constipation.

Clinical Trial Registration Number: Japic CTI-163167.