Study to examine laxative use in children

The US Food and Drug Administration (FDA) has awarded a research grant to the Children’s Hospital of Philadelphia to study the safety of an adult laxative commonly used in children.

The study will focus on polyethylene glycol 3350 (PEG 3350), the active ingredient in Miralax and similar laxatives, to gather data about its intestinal absorption in children, especially the very young and children suffering from chronic constipation, who may take the medication for a long time. Laxatives containing PEG 3350 have long been given to children in the belief that they are safe because children’s intestines absorb only a very small amount of the chemical. Data on absorption in children are sparse, however, according to the FDA.

Researchers will also investigate whether PEG 3350 is associated with neuropsychiatric effects, such as obsessive-compulsive behaviors, tremors, and tics, which have been reported to the FDA in children taking the laxative.

Another issue the study will address is metabolism and blood levels in children of ethylene glycol and diethylene glycol, potentially toxic contaminants arising from the manufacturing process. In its briefing about the research grant, the FDA mentioned finding trace amounts of the chemicals in some batches of Miralax that it tested in 2008 because some of the reported adverse effects from laxatives are associated with ethylene glycol ingestion.

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Trace amounts of ethylene and diethylene glycol are permitted in drugs and considered safe by the FDA when the drugs are used according to approved labeling. In the case of PEG 3350 laxatives, the approved use is once a day in adults for no longer than 7 days. Safety in children and during exposure to laxatives over a prolonged period are unknown. 

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