The efficacy and safety of polyethylene glycol 3350 in the treatment of constipation in children

Pediatric Nursing, May-June, 2004 by Margo A. Kinservik, Margaret M. Friedhoff

Prior to enrollment in the study, children who were diagnosed with constipation alone or with encopresis where treated with PEG 3350. The initial dose was 0.8 g/kg/day divided into two doses. The PEG solution was mixed according to the manufacturers' directions. Parents were instructed to adjust the dose of the medication as needed to produce two, soft, painless stools a day.

After they were enrolled in the study, the parents of the children were interviewed using a structured questionnaire. They also were asked the dose of PEG 3350 given, the beverage used to mix the PEG 3350, ease of mixing, and compliance with taking the medication. Parents were asked questions about possible adverse effects of the medication, including stool consistency, frequency, abdominal pain, flatulence, nausea, and bloating. Children were asked if they liked the PEG 3350 and if they preferred it over laxatives they had taken in the past.

A physical examination of the child was performed after the interview and blood was drawn for the following tests: hemoglobin, hematocrit, serum electrolytes, blood urea nitrogen, serum creatinine, osmolality, albumin, aspartate aminotransferase, and alanine aminotransferase (ALT). Results of the laboratory tests were considered abnormal if they were outside of the age and sex established reference range by even one point. Ten children did not have osmolality measured. Nine had slightly elevated ALT levels (< 1.5 times normal). Eight of these children had their ALT level rechecked within 8 weeks (seven were still on PEG 3350 therapy). Seven of these patients had normal ALT levels, while one child had a slightly elevated level (< 1.2 times normal). Three children had an elevated aspartate aminotansferase level (< 1.5 times normal), but all had normal levels when retested while still receiving PEG 3350. The dose of PEG 3350 and the duration of therapy were not significantly different in the children with abnormal levels compared to the children with normal laboratory levels. Laboratory studies were not done prior to starting PEG 3350.

A variety of beverages was used to mix the PEG 3350 including fruit juice, milk, fruit punch, and water. All families found it easy to prepare the solution. All of the 68 children who had been on other laxatives preferred the PEG 3350 solution. Ninety-three percent of the children in this study liked the PEG 3350 solution. Daily compliance with the therapy was assessed by parent recall and diaries. Compliance was described as good in 90% of the children during therapy.

The investigators concluded that PEG 3350 did not adversely affect fluid and electrolyte balance. Because the abnormal liver function tests were normal on all but one child on retesting, and a cited study indicated no need for retesting on mildly elevated levels of aminotransferase, the investigators concluded that the abnormal ALT levels were clinically insignificant and were not related to therapy with PEG 3350.

In this study, therapy with PEG 3350 for a mean of 8.7 months did not show any major clinical adverse events. The therapy was well accepted by the children studied. The authors recommend a study of a larger number of children followed for a longer period of time to ensure the absence of any rare side effects associated with PEG 3350.