We gave DS Miralax because he was always constipated and screaming when he pooped. We gave him about 1/4 tsp in his milk once a day. It made things so much better. You may have to play around with the dosage since some kids need more or less, but it should work within a day or two. Poor kid!
We also use Miralax - mixed into her morning chocolate milk. He may need a little more to start, about half a dose is what we started with. Right now she gets about a teaspoon every other day to help keep it from hurting her when she goes. Plus because it hurt she would hold it and make it even worse in the end.
We also use Miralax. The pediatrician said to mix it in clear liquid so we mix it with a mixture of apple juice and water. We've been giving it to her for about 6 months and the difference has been huge. She rarely has a painful BM whereas before she was constantly having constipation issues.
Re: Give me the details on Metamucil and toddlers