A water retention laxative such as Miralax is the type of laxative most commonly recommended by pediatric healthcare providers for the treatment of encopresis. When Miralax is prescribed, parents are usually advised to give one or more "caps" or "half caps" of the powder diluted in water. A "cap" is the amount recommended on the container and is therefore assumed to be the "standard" dose. However, the fact is that there is no one dose that is the most efficacious for all children. A cap or half cap may be too much or too little as evidenced by its effect on stool consistency. In my book, The Ins and Outs of Poop, I strongly recommend dosing PEG laxatives like Miralax by the teaspoon (one cap is approximately 5 level teaspoons). Dosing by teaspoons makes it much easier to determine the most efficacious dose for each child.

Why is getting just the right dose so important?

The key to successfully treating encopresis is to find that dose of a laxative that enables a child to have 1 to 2 medium-to-large, very comfortable BMs a day, 5-7 days a week that are softer than the normal "toothpaste" consistency. 

The desired consistency is like that of pudding or applesauce but not watery.

Over the many months required to effectively treat encopresis, the laxative dose may need to be raised or lowered in small increments to maintain the desired consistency until withholding has stopped and the rectum has shrunk back to it's normal size.

A mother recently told me that when she sought advice from a counselor about her 5 year old son’s encopresis, the counselor told her that his accidents and his seeming indifference to having poop in his underwear was due to her poor parenting. Needless to say, this mother was very relieved to hear from me that her son’s soiling behavior was not her fault. 

Unfortunately, there are still many medical and nonmedical healthcare providers who know very little, if anything, about encopresis.  Encopresis is not a topic that is typically covered in detail in medical school (general or pediatric).

When the parent of a child with bowel problems is looking for a healthcare provider for advice or guidance, their first question should always be, “How familiar are you with functional constipation or chronic constipation or encopresis in children?”

If the provider says that they do know about this condition, the second question to ask is, “How many children with this condition have you seen in your practice?” Ideally, what you want is a provider with both knowledge and clinical experience.

(If you cannot find a provider who has either or both of these traits, but you do have a provider you like and trust, I am always available to speak with the provider regarding your child's specific situation. Please visit Consultations and sign up for a free 15-minute telephone consultation.)

Unfortunately, many pediatricians and/or their staff are not trained or experienced in treating complicated poop problems like encopresis and chronic constipation.

Here is an email I recently received, reprinted with the parent's permission:

Hi Dr. Tom,

I'm currently pretty livid, and a little bit defeated. My 3.5 year old son's pediatrician referred us to a pediatric GI clinic to rule out any other underlying causes for his constipation. He's on a very large daily dose of Miralax and his poops are extremely soft.

We saw the nurse practitioner at the clinic. The good news is that she doesn't think there is anything else going on in addition to what we already know: his rectum is stretched out, so things do not work exactly the way they should.

We were in a pretty good place before the appointment. He was having a large poop daily and, with a few recent exceptions, he was going in the potty. It took us months to get there. But she did a rectal exam and not in a way that I liked. At all.

She didn't actually tell him she was going to do it. She made him cry trying to get him on his side, until I stepped in and got him to roll over without tears. Then she just told him, "This is going to feel like pooping backwards," and stuck a finger in. Given that he has fear issues regarding pooping, that does not seem like a wise thing to say to comfort him.

The mother of a child with encopresis recently told me that when she asked her pediatrician if Miralax might be the cause of her son’s frequent poop accidents, her pediatrician said, “Absolutely not!  In all my years of practice I have never seen Miralax cause accidents!” 

My first thought was that this doctor must not have treated many children with encopresis.

Any PEG or water retention laxative such as Miralax can cause stool to leak, sometimes uncontrollably, if given in unnecessarily high doses. This is, unfortunately, very common. In my experience, the main reason why children are unintentionally given more (or sometimes less) laxative than they need is because parents and even some healthcare professionals think that “one cap” of the PEG powder is the “standard dose” even for children, so that is how it is typically prescribed. But, often that is far more than the child needs.

The last thing a child (or their parent) wants is to soil or leak MORE than usual! In my experience, the most common reason parents feel that laxatives don't work for their child is that their child has been on an incorrect dose.

The fact is that there is no one dose that is correct for all children. A dose that works for one child may be too much or too little for another child. That’s why I always advise that PEG laxatives be prescribed by the teaspoon and not by the cap, keeping in mind that one cap equals five level teaspoons.  My book describes in detail how to determine the correct dosage for your child.