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

The investigators emphasize that there have been no convincing studies that demonstrate the superiority of any class of laxative. However, the preference for PEG 3350 in this study suggests that this laxative may be easier to administer to children who need laxative treatment for constipation. This study showed that PEG 3350 was similar to lactulose in improving stool frequency, form, and ease of passage in the children studied with constipation. PEG 3350 decreased the total colonic transit time compared to lactulose. The investigators suggest that one limitation of this study was that only a single daily dose of each laxative was tested and, in the usual treatment of constipation, the number of doses is often varied based on clinical results. The authors also state that further studies of PEG 3350 are necessary to determine the safety and optimum dose of this laxative.

Study #4. Youssef et al. (2002) studied the dose response of PEG 3350 without electrolytes (MiraLax) for the treatment of childhood fecal impaction. Their study looked at the use of PEG 3350 for treatment of a fecal impaction rather than the long-term treatment of constipation. Youssef et al. used a prospective, double-blind, parallel, randomized study of four different doses of PEG 3350 to determine the dose that would be effective and safe in the treatment of fecal impaction in children.

Patients enrolled in this study were children presenting to the pediatric gastroenterology clinic with constipation and/or fecal soiling. All enrolled had to have evidence of a fecal impaction by abdominal and rectal examination. Clearance of the fecal impaction was the primary outcome measure of this study. Diaries were provided to the parents to report stool characteristics and monitor symptoms. The diaries had analog scales that were numbered from 0 (minimum) to 10 (maximum). The parents were to record each defecation, including the consistency of the stool, straining while passing the stool, the amount of stool, associated gas, and cramping using the analog scale.

The safety of PEG 3350 as disimpaction laxative was measured by laboratory evaluation of creatinine, blood urea nitrogen, calcium, phosphorous, magnesium, bicarbonate, chloride, potassium, sodium, and serum osmolarity. These were checked both before and after treatment with PEG 3350.

Only new patients were enrolled in the study. A telephone interview was conducted initially to screen the patient for functional fecal retention using the Rome criteria (Rasquin-Weber et al., 1999). Children of both sexes were eligible for the study if they were between 3 and 18 years of age. Exclusion criteria included any previous gastrointestinal surgery, an allergy to PEG solution or phosphates, and signs and symptoms suggestive of a bowel obstruction. Participants had to discontinue all medications for constipation at least 7 days before the initial examination.

Ten children were enrolled in each of the four dosage categories. They were randomly assigned to a dose. The doses of PEG 3350 were: 0.25 g/kg/day, 0.5 g/kg/day, 1 g/kg/day and 1.5 g/kg/day for 3 consecutive days. A maximum dose of 100 g per day was set. All medications were dispensed premixed in a clear liquid in a container labeled only with a random number. Written instructions with the dose to be taken daily were given to the patients along with a measuring cup. All were to take the medication in the morning with breakfast. If the total dose was greater than 240 ml, the remainder of the dose was divided and given at the remaining meals that day. Investigators were blinded to the dose given until all patients had completed the study and all the data had been turned in. All patients were examined 48 hours after finishing the last dose of medication to assess for clearance of the fecal mass, collect diaries, assess for adverse events, and collect the medication bottles.