PEG 3350 Use Not Associated With Abnormally High Glycol Levels in Children

Columbus, OH — June 2018

Polyethylene glycol (PEG) 3350, most commonly sold as MiraLAX, is an over-the-counter laxative frequently given to children to treat constipation. However, recent reports by some parents of behavioral changes in their children after taking the laxative have spurred the U.S. Food and Drug Administration to request research into whether PEG 3350 contributes to neuropsychiatric events in children.

One concern about PEG 3350 is that it might contain trace amounts of potentially neurotoxic compounds ethylene glycol, diethylene glycol and triethylene glycol. In a new study in The Journal of Pediatrics, physician-scientists at Nationwide Children’s Hospital evaluated the levels of these compounds in the blood of children taking PEG 3350 as well as untreated children.

The researchers found very low levels of all three compounds in both treated and untreated children. Baseline levels of ethylene glycol and triethylene glycol did not differ between the groups, while diethylene glycol levels were actually lower in the children receiving therapy than in the controls.

The fact that all three compounds were found in the blood of the control children indicates that all children are exposed to these compounds routinely.

The study’s lead author, Kent Williams, MD, a member of the Division of Gastroenterology at Nationwide Children’s, says that adults working in the lab also had detectable levels of these compounds in their blood.

Where does this exposure come from?

“The FDA has approved certain PEG polymers to be used as a food additive, as well as in commercial products like lotions, creams, and make-up,” says Dr. Williams.

The researchers also found that chronic use of PEG 3350 does not result in a sustained elevation of these compounds in the blood; the greatest levels of ethylene glycol and diethylene glycol measured after PEG 3350 treatment were lower than the greatest levels of these compounds measured in control samples.

“In fact, one control child’s level of ethylene glycol was almost two times higher than the highest concentration of ethylene glycol found in children treated with PEG 3350,” says Dr. Williams, who is also an assistant professor of Clinical Pediatrics at The Ohio State University College of Medicine.

Dr. Williams and his colleagues conclude that potential toxic side effects of PEG 3350, which contains very small, trace amounts of ethylene glycol and other compounds, are extremely unlikely. The reports of behavioral issues are probably not due to taking the laxative, but rather, tend to occur in association with constipation. Behavioral problems are common in children with constipation and include aggression, depression, anxiety, and increased emotional reactivity.

“What I tell parents is the potential side effects of MiraLAX are very unlikely and the complications from uncontrolled constipation can be quite severe,” says Dr. Williams.

Williams, KC, Rogers, LK, Hill, I, Barnard, J., and Di Lorenzo, C. (2018). PEG 3350 administration is not associated with sustained elevation of glycol levels. The Journal of Pediatrics 195: 148-153.