Glucomannan is not effective for the treatment of functional constipation in children: a double-blind, placebo-controlled, randomized trial

Background & aims: Treatment measures for constipation in children are often not satisfactory. The aim was to assess the efficacy of glucomannan (GNN) as a sole treatment for functional constipation.

Methods: Children aged 3-16 years with functional constipation according to Rome III criteria were randomly assigned to receive GNN (2.52 g/d) or placebo for 4 weeks.

Results: Of the 80 children, 72 (90%) completed the study. The primary outcome, treatment success (≥3 stools per week with no soiling), was similar in the GNN (n = 36) and placebo (n = 36) groups (relative risk 0.95, 95% CI 0.6 to 1.4). In the GNN group, the stool consistency score was higher at week 1 (P < 0.0001), lower at week 3 (P = 0.008), and similar at weeks 2 and 4. Stool frequency was higher only at week 3 (P = 0.007). Abdominal pain episodes were more frequent in the GNN group at week 1 (P = 0.04) and week 4 (P < 0.0001) but were similar between groups at weeks 2 and 3. No difference was observed in the frequency of any other secondary outcome or adverse event.

Conclusions: In our setting, GNN, as dosed in this study, was not more effective than placebo in achieving therapeutic success in constipated children. The trial was registered at ClinicalTrials.gov (http://clinicaltrials.gov), number NCT01151878.