Constipation in children accounts for approximately 3 percent of outpatient visits to general clinics for children per year. Treatment can include dietary and behavior modifications, counseling, and the use of various laxatives and stool softeners. Polyethylene glycol 3350 (PEG) is an osmotic laxative that currently is being used to cleanse the gastrointestinal tract before diagnostic or surgical procedures in children. PEG is a nontoxic and highly soluble compound that is not absorbed in the gastrointestinal tract. This compound, without electrolytes, comes as a powder that is palatable when dissolved in water or juice. PEG has proved to be effective in the short-term treatment of constipation in children, but there currently are no published studies of long-term safety. Pashankar and colleagues evaluated the clinical and biochemical safety of long-term PEG therapy in children with chronic constipation. They also examined acceptance of this therapy in young children.

The trial was a prospective observational study of children with chronic constipation, which was defined as at least three months of at least two of the following symptoms: hard stools, encopresis, painful defecation, or fewer than three bowel movements per week. After enrollment in the study, patients received PEG therapy at 0.8 g per kg per day, and use of other laxatives was stopped. Parents were instructed to dissolve 17 g of PEG powder in 240 mL of water and give the appropriate amount of the liquid in two divided doses. Parents could adjust the dosage until the child starting having two soft, painless stools per day.

Parents were allowed to taper the dosage over time, based on the child's response to therapy. Follow-up after the initiation of therapy was performed by giving parents a standard questionnaire that reviewed the dosage of PEG given, medication compliance, the beverage used to prepare PEG, ease of mixing, overall improvement in bowel movements, and any adverse effects. The children were asked whether they liked the medication and if they preferred it to other laxatives. Blood was obtained at the follow-up appointment to evaluate the biochemical effect of PEG therapy.

There were 83 children who participated in the study, with an average age of 7.4 years (range, 2.0 to 16.9 years). The average duration of therapy for the study was 8.7 months (range, 3 to 30 months). The mean dosage of PEG was 0.75 g per kg per day. No serious adverse effects were reported except for a transient elevation of the alanine transaminase level in nine children that appeared to be unrelated to PEG therapy. Minor adverse effects such as diarrhea were controlled easily with a reduction in the dosage of PEG.

Compared with previous laxatives, PEG was preferred by all of the children, and daily compliance was 90 percent in all of the children. Ninety-one percent of the caregivers reported a definite improvement in bowel-movement patterns with PEG therapy.

The authors conclude that PEG therapy is safe and well accepted in the long-term treatment of chronic constipation in children. They recommend that PEG be considered first-line treatment in these patients because of its high rate of acceptability.