A related discussion,
poop was started.
A related discussion,
poop smears was started.
How much water does he drink? Kids nowdays drink too much sodas, Kool-Aid and juice. Juice should be 100% juice, not the junk they sell nowdays full of sugar and artificial ingredients. My 7 yr old has BM problems, hard stools, etc. I push the water and limit juices and sodas. Sufficient water is usually the key to regular bowel movements.
Try 400 mg magnesium too as this is a good laxative. Try lots of fiber too; at this age it sometimes is hard to get them to eat fruit with the peel but try applesauce with no artificial ingredients or sugar added, raisins, etc.
I have had a problem like this with two of my children. What months of guesswork boiled down to was stop giving them milk.
The milk keeps them from going for a few days, (or more) and then when they finally DO go, it hurts so bad they scream in pain and try to hold it in, thus making the situation worse.
I can't say that this is the problem your having, but it couldn't hurt to try it. You may be surprised. I was.
Keep him on the regimen prescribed by your doctors. After a while of having bowel movements and experiencing no discomfort, he will stop associating bowel movements with pain. This is a typical reaction of children who have become seriously constipated and then avoid bowel movements because they've come to expect that the experience will be unpleasant. It takes time for them to develop a different expectation.