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Release: Sept. 13, 2001

UI studies palatable laxative for children with chronic constipation

IOWA CITY, Iowa -- Trying to treat constipation in a child can be a difficult experience for child and parent alike. Milk of magnesia and mineral oil -- two traditional remedies -- don't taste very good, which can affect a child's ability to use them effectively as therapies.

However, families might now be more likely to turn to using polyethylene glycol (PEG) 3350, a palatable powder-form laxative available by prescription that can easily be dissolved in a child's favorite beverage. University of Iowa Health Care researchers studied the optimal dosage at which the therapy, without added electrolytes, can safely and effectively treat constipation in children. The findings will appear in the September issue of The Journal of Pediatrics.

PEG 3350 already had been studied as a treatment for adult constipation; however, it was not clear what dose was safe and effective for children, said Warren Bishop, M.D., UI associate professor of pediatrics and director of the UI Pediatric Gastroenterology Clinic. Bishop co-authored the study with Dinesh Pashankar, M.D., UI assistant professor (clinical) of pediatrics.

"Polyethylene glycol can replace traditional treatments, including milk of magnesia and mineral oil, that have undesirable characteristics," Bishop said. "These older medications are effective but very difficult for most children to take reliably."

Bishop explained that polyethylene glycol products that contain salt and other electrolytes have been available for years. These solutions are used to flush out the intestines of a person prior to surgery or colonoscopy but also are very unpalatable because of their high salt content. The salt is necessary to prevent salt-depletion when taken in large volume. However, more recently, PEG 3350 in an electrolyte-free form has been made available.

"Our innovation is to use the PEG without salt in small volumes each day in order to soften the children's stools and treat their constipation," Bishop said. "Because we're using a small volume, we're not causing a significant loss of liquid stool or electrolytes."

Bishop and Pashankar studied 20 children ranging in age from 18 months to 11 years (average age 6 years) who had chronic constipation, which means a stool frequency of fewer than three per week. Some of the children also had encopresis, which is the leakage of soft stool around impacted stool.

"The typical child with chronic constipation has infrequent, painful stools," Bishop said. "Many children in our study were fearful of using the toilet. Some also were holding on to their

stools voluntarily and then having what we call overflow incontinence -- leakage of the stool into their underwear."

PEG increases the water content of feces, making them move more easily and painlessly through the intestines. After treatment with PEG, the children's stool frequency increased from 2.3 to 16.9 per week, or about two bowel movements per day. While that may seem higher than normal, Bishop said the increased number of stools helps the children resolve their constipation.

"In addition to increasing the stool frequency, we also aimed to allow the children to have stools that were soft to slightly runny so that any pain associated with defecating would be alleviated," Bishop explained.

Children in the study had a marked improvement in stool consistency, changing from hard to soft and slightly loose stools. Incidents of soiled underwear in the nine children who had leakage problems also decreased from 10 incidents a week to only slightly more than one.

Patients' reports of these improvements in their bowel movements were noted rapidly, with 12 children reporting improvement within the first week, and the remaining eight participants reporting success with the therapy during the second week of treatment.

From the patient's point of view, a particularly important aspect of the treatment is that the medication is tasteless, dissolves completely and does not alter the taste of the beverage in which it is mixed. Children participating in the study used beverages including Kool-Aid, fruit juices, Crystal Light, water and cow's milk.

"The polyethylene glycol helped us achieve control of constipation quite easily in all of the children studied, and it was uniformly found to be palatable, so the regimen was therefore excellent," Bishop said.

This study was funded by Braintree Laboratories, Inc., the manufacturers of Miralax (PEG 3350).

As with all medical care, it is best to consult with a personal physician before making any changes in your or a dependent's health routine.

Parents interested in learning more about PEG therapy for a child are urged to contact their family physician or the UI Pediatrics Gastroenterology Clinic at (319) 356-2950. Visit the UI Pediatric Division of Gastroenterology online at

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