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Dosing MiraLAX for Your Constipated Child

How to dose Miralax for a child.

For resolving bedwetting and accidents, there is no doubt daily enemas work far better than MiraLax. Doctors who push MiraLax because they consider enemas “too aggressive” or a “last resort” are steering patients in the wrong direction.

But MiraLax can help.

I consider laxatives such MiraLax (generically called P.E.G. 3350) an important adjunct to M.O.P., the daily enema protocol that resolves bedwetting and accidents.

MiraLax is also useful for children who are chronically constipated but who are not having accidents and children who have “graduated” from M.O.P. but aren’t out of the woods. (Constipation has a way of creeping back.)

Yes, I am well aware of the controversy over MiraLax safety, and I address this issue in "Is Miralax Poisoning Children?" and “Is MiraLax Safe for Kids?” If you are not comfortable giving your child MiraLax, that is fine. You can substitute lactulose (brand name Kristalose), a prescription medication that comes in liquid or powder, magnesium citrate, or any alternative laxative you find works for your child.

Today’s post focuses on a question I hear often: How much MiraLax should I give my child?

Finding the right dose can be tricky. Parents tell me, “My child swings between hard poop and diarrhea — we can’t find a happy medium.”

The instructions on the MiraLax bottle are not useful for chronically constipated children. Neither are the one-size-fits-all instructions offered by many physicians.

Why Use Miralax?

If your child has accidents or wets the bed, this means a large, hard mass of poop has formed in the rectum and is wreaking havoc on the bladder. A top-down laxative like MiraLax is not likely to break up this hard mass — that’s like using a trickle of water to clean a dish encrusted with last night’s dinner remnants.

Bottom-up therapy, like a daily enema (a gentle spray into the child’s bottom, sometimes with ingredients to stimulate the colon to contract), is far more effective at cleaning out the rectum. Daily enemas keep the colon clear so it can shrink back to size and regain tone and sensation. And yes, they're safe.

So where does MiraLax come in? MiraLax draws water into the colon, softening poop and easing its journey to the rectum and out the door.

MiraLax helps keep stool mushy, so pooping doesn’t hurt. It is pain that causes kids to withhold stool in the first place (“fear” of the toilet is usually fear of painful pooping). So, poop must be mushy enough to plop out without effort on the child’s part.

Even children following a daily enema protocol should poop at least once a day on their own (not just right after the enema), and the poop should come out like soft-serve ice cream. Yes, that mushy.

Finding the right dose can take trial and error. Ultimately, what matters is not how much laxative your child takes in; it's the consistency of what comes out the other end. To achieve mushy poop, some kids need a lot more MiraLax than others.

Here’s how to find the right dose for your child. (The guidelines apply whether or not your child is on the Modified O'Regan Protocol.)

•Start the child on one capful (17 grams) a day, mixed in 4 to 8 ounces of water, juice, or Gatorade. Mix until the drink is completely clear; you shouldn’t see MiraLax particles floating around.

If you're using lactulose powder, substitute 10 grams lactulose for the 17-gram capful of MiraLAX. But if you're doing the high-dose a clean out we describe in It's No Accident, use MiraLAX; better yet, use enemas.

•Have the child drink MiraLax at roughly the same time every day. It’s fine for the child to take half the dose twice a day instead of the full dose at once.

•Evaluate the child’s poop consistency yourself. Yes, you! Second-hand reports from 5-year-olds are often unreliable.

•If the poop is harder than total mush — if you see pellets, a log, or a thick bumpy sausage — increase the dose by ¼ to ½ a capful per day. If the poop is diarrhea, decrease the dose by ¼ to ½ capful. Continue to monitor the poop’s consistency, and keep adjusting.

•If, after several days, you still can’t find that happy place between too hard and too loose, this means your child has a hard lump of poop clogging the rectum. You’ll need to start daily enemas, if you haven’t already.

Don’t assume that watery poop or diarrhea means your problem is solved; more likely, it means that softened poop is just oozing around the hard lump.

•If your child feels bloated on MiraLax or if MiraLax makes the belly pain worse, try a different osmotic laxative or suppositories alone for a few days before restarting. Or skip the laxatives and simply do enemas .

•If your child is constipated but isn’t having accidents of any kind, a week of daily enemas or suppositories will probably suffice to unplug the rectum. After that, MiraLax will be easier to dose.

•Keep your child on MiraLax for 3 to 6 months after symptoms resolve.

I realize the MiraLax bottle says not to take the product for more than 7 days. However, a) 7 days will do nothing to resolve chronic constipation, and b) countless studies indicate long-term use of MiraLax is safe in children. (I delve into these studies in It's No Accident.)

The habit of holding poop is often deeply ingrained in children — most of these kids have been withholding since they were potty trained. Extended use of MiraLax will help them develop healthier pooping habits.

•Make sure your child drinks plenty of water, gets a lot of exercise, and primarily eats unprocessed foods, especially fruits and vegetables.

Miralax is not a lifetime solution to constipation!

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