Review: high-quality evidence on the effectiveness of laxatives for functional constipation in children is limited
Are laxatives and dietary measures effective for functional constipation in children?
Included studies compared osmotic, bulk-forming, stimulant or emollient laxatives, lubricating agents, or dietary measures with placebo, no treatment, or alternative treatments in children ⩽18 years of age who had functional constipation. Exclusion criteria included studies of children with psychiatric disease, organic constipation, exclusively non-retentive faecal incontinence, or mental handicap. Outcomes included treatment success (defined by individual studies) or defecation frequency.
Medline and EMBASE/Excerpta Medica (to Dec 2007) and reference lists were searched for randomised controlled trials (RCTs), comparative clinical trials (CCTs), or crossover studies. 28 studies (n = 1912, duration of follow-up 2 d to 12 mo) met the selection criteria: 21 RCTs, 1 CCT, and 6 crossover studies. 9 studies evaluated polyethylene glycol (PEG); 7 evaluated lactulose; 3 studies each evaluated cisapride, senna, and mineral oil; 2 evaluated fibre (cocoa husk supplements or glucomannan); and 7 evaluated other treatments. 10 studies were of high quality (Delphi list score ⩾6 out of 10).
The table shows the main results. 1 high-quality study found that PEG increased weekly bowel movements more than placebo (n = 51, mean treatment difference 1.64, 95% CI 0.99 to 2.28). 2 studies (n = 102) found that PEG increased frequency of bowel movements more than lactulose; 3 (n = 412) found no difference between treatments. Results for other laxatives were not consistent.
In children with functional constipation, polyethylene glycol was better than other laxatives for treatment success; results for defecation frequency were inconsistent.
Pijpers MA, Tabbers MM, Benninga MA, et al. Currently recommended treatments of childhood constipation are not evidence based: a systematic literature review on the effect of laxative treatment and dietary measures. Arch Dis Child 2009;94:117–31.
The comprehensive review by Pijpers et al provides the first quality evaluation of current treatments for functional constipation in children. Of the 736 studies found, only 28 met inclusion criteria and only 10 were rated as high quality. Lack of uniform outcome criteria hindered the data analysis. The only outcome that was consistently reported was frequency of defecation; however, this was not seen as an adequate definition of constipation. The authors concluded that more high-quality RCTs that use placebos when appropriate, conceal treatment allocation, blind evaluators, and use intention-to-treat analysis are needed. Although Pijpers et al concluded that there is insufficient evidence to support use of laxatives, there was limited evidence to support use of PEG with or without electrolytes. Of the 10 high-quality studies, 5 involved PEG or PEG 3350 with electrolytes; both preparations were more effective in achieving remission in functional constipation than placebo or lactulose. These findings were confirmed in a recent systematic review of PEG use in paediatric functional constipation.1 Overall, fibre was no more effective than placebo. Clinical practice guidelines describe PEG as odourless and tasteless, with superior paediatric palatability and acceptance, although more safety evaluation is needed.2 Now eMedicine provides dosing recommendations for PEG in children as young as 6 months.3 PEG has been available in the USA without a prescription since 2007 but is only approved for over-the-counter use in those ⩾16 years of age. Thus, parents will continue to need professional guidance on managing functional paediatric constipation.