A recent article in the New York Times identifies the possible overuse of Miralax for treating chronic constipation in children. Many take it on a daily basis for years, despite the fact that it is only approved for use in adults. As a pediatrician I have prescribed Miralax many times, and find it to be a very useful medication. The problem comes when only the symptom, and not the underlying cause, is treated.
In my experience the cause of chronic constipation is usually not insufficient fiber in the diet, but rather a combination of a habit of stool holding with sometimes complex emotional issues around autonomy and control (the exception being an underlying neurologic or other medical condition.) I'm all for a healthy diet, but if you make this an issue about eating more fruits and vegetables, you may be simply shifting the battleground from one end to the other. It is best to avoid battles over either what goes in or what comes out, because in these battles the child, by using his body, will always win.
I hope readers don't mind some details-as a pediatrician I have to be comfortable talking about poop. On excellent use for Miralax is for a toddler who has a hard painful stool and then holds in his stool for fear of repeating this experience. This may be more likely to happen in a child who is sensitive not only to bodily sensations but also other forms of sensory input, such as sound and touch. This problem can occur whether or not a child is in diapers. It is best nipped in the bud. Miralax acts by drawing water into the stool. If you give the right amount, the stool is too soft for the child to hold it in. With time the child will forget the painful experience and then go back to normal stooling.
Stool holding and conflicts around toilet training may also occur if a child feels things are out of control in some other aspect of his life. For example, most parents intuitively recognize that toilet training a toddler around the time of the birth of a sibling is not a good idea. One child I took care of dug in his heels around potty training when his parents were going through a difficult divorce.
Parents who have dealt with this problem know that kids can be very adept at holding in stool. They may stand in a corner turning red in the face with effort. This may be interpreted as trying to push the poop out, but most of the time what is actually happening is that they are working to hold the stool in. Just as biceps get strong when you lift weights, the anal muscles can get very strong with repeated use in this way. If this cycle is not broken, kids can go on to have problems for many years. However, with time and careful attention, kids can learn to use their muscles the right way and to have a healthy relationship with their body and bowel habits.
There are often tremendous social pressures on parents to toilet train their children. When parents come to see me in my behavioral pediatrics practice, they often have had ongoing conflicts with their child about sitting on the potty, but have recognized that this approach is not working. They may even wish to have their child take charge of the issue, only to be thwarted by pressures in the school setting. I am all for using motivation for encouragement when a child is ready. Pediatrician Barton Schmitt coined the term "poop candy" for rewards for pooping in the potty. But if a child is not ready, either physically or emotionally, even the promise of a trip to Disney World will not get him to poop in the potty.
Toilet training occurs at a time when children are taking ownership of their bodies. Eric Erikson referred to it as the stage of autonomy vs. shame and doubt. As much as is possible, its best to simply let a child take charge. If problems arise, short term use of Miralax to avoid stool holding while the underlying issues are addressed is certainly reasonable. But it should not be used for long-term treatment. I am not speaking to the safety of the drug, because its long-term risk is not known. Rather, using any drug for years without in- depth exploration of the cause of the problem, a trend far too common in our medication-happy culture, is not a good idea.