Background: Stool softening is a physician's first step in the management of chronic constipation.
Aim: To compare stool softening (stool water content) and laxative efficacy of psyllium hydrophilic mucilloid vs. docusate sodium.
Methods: The multi-site, randomized, double-blind, parallel-design study of 170 subjects with chronic idiopathic constipation involved a 2-week baseline (placebo) phase followed by 2 weeks of treatment. The treatment phase compared psyllium (5.1 g b.d.) plus docusate placebo to docusate sodium (100 mg b.d.) plus psyllium placebo. Stools were collected and assessed.
Results: Compared to baseline, psyllium increased stool water content vs. docusate (psyllium 2.33% vs. docusate 0.01%, P = 0.007). Psyllium also increased stool water weight (psyllium 84.0 g/BM; docusate 71.4 g/BM; P = 0.04), total stool output (psyllium 359.9 g/week: docusate 271.9 g/week; P = 0.005), and O'Brien rank-type score combining objective measures of constipation (psyllium 475.1; docusate 403.9; P = 0.002). Bowel movement (BM) frequency was significantly greater for psyllium (3.5 BM/week) vs. docusate (2.9 BM/week) in treatment week 2 (P = 0.02), with no significant difference (P > 0.05) between treatment groups in treatment week 1 (3.3 vs. 3.1 BM/week).
Conclusion: Psyllium is superior to docusate sodium for softening stools by increasing stool water content, and has greater overall laxative efficacy in subjects with chronic idiopathic constipation.