Osmotic laxatives produce the best results. Fiber and behavior modification may have a role. Increased fiber and behavior modification are the most often recommended first steps in managing chronic functional constipation (CFC) in children, but only limited evidence supports this approach (strength of recommendation [SOR]: B for fiber, 1 randomized controlled trial [RCT]; C for behavior modification, 1 small trial).
For pharmacologic management, the best evidence supports osmotic laxatives (SOR: A, 6 fair- to good-quality RCTs).
CFC with or without encopresis is a common pediatric problem that’s distressing to both the child and family. High-quality RCTs on managing CFC are lacking. Our search located 7 relevant RCTs1-7 and 2 relevant systematic reviews.8,9 The TABLE summarizes the RCTs.
How laxatives for childhood constipation compare
|INTERVENTION VS COMPARISON||NNT||EFFECTIVE DOSE||AVERAGE|
|Glucomannan vs placebo1||3||100 mg/kg/d||$10-$30*|
|PEG + E vs placebo2||2||7-42 g/d||$14-$60*|
|PEG + E vs lactulose3||4||3-6 g/d vs 6-12 g/d||$20 vs $20|
|PEG + E vs mineral oil|
for disimpaction over 2 days 5
|5||20 mL/kg/h×4 h/d|
30-120 mL BID
|$20 vs $20|
|Mineral oil vs senna6||3||3 mL/kg/d vs 1-4 tab/d||$8 vs $5|
|Lactulose vs senna7||4||15 mL/d vs 20 mL/d||$20 vs $10|
|*Retail price varies by manufacturer.|
|NNT, number needed to treat; PEG + E, polyethylene glycol 3350 plus electrolytes.|
Fiber may help—and doesn’t hurt
A fair-quality crossover RCT (31 children, mean age 7 years, with CFC) compared fiber (glucomannan) with placebo for 4 weeks.1 More children were successfully treated with fiber than placebo (45% vs 13%; number needed to treat [NNT]=3.125; P<.05). Parents rated children as doing better on fiber (68% vs 13%), and abdominal pain occurred less often (10% vs 42%; P<.05). No adverse effects were associated with fiber.
Osmotic laxatives, especially PEG, get results
A recent high-quality RCT compared the osmotic laxative polyethylene glycol 3350 plus electrolytes (PEG + E) with placebo in 51 children with CFC, 2 to 11 years of age.2 The mean number of defecations per week was higher for children on PEG + E (3.12 vs 1.45; P<.001); straining or pain and stool consistency improved.
One good-quality RCT (100 children, 6 months to 15 years old with CFC) compared PEG + E with lactulose.3 Both significantly increased stool frequency and decreased encopresis. However, PEG + E had a markedly higher success rate (56% vs 29%; NNT=3.7; P=.02). The 8-week trial found significantly more complaints about bad taste in the PEG + E group; the lactulose group reported higher rates of abdominal pain, straining, and pain at defecation. The only dropout because of adverse events (bad taste) occurred in the PEG + E group.