my child did this. He started wearing slim pants. I stayed with the medicine, and his body adjusted. He is now wearing size 18 pants and 12 years old. And he is tall to boot.
I find by staying with the meds, his body adjusted to it. his pediatrician said the same thing. you have to give his body a chance to get used to it and it does take a while.
does he make up for eating later on? Mine would start by having a candy bar when he came home. That seemed to jump start his appetite. BUT he did get skinny, even though he gained weight, just not as much as he grew in height.
Let me ask you, is the med helping him where he needs it, like in school, etc? I feel it is important that if the med is working where you need it to be and your son is eating but not as much and/or later on, it is worth it. Your son's weight will catch up but it will be a while.
We went through this for about a year. And if you saw my son, you would never know we ever did, honestly!!
That is my experience and opinion!
My daughter would have trouble eating at the start of medication 3 years ago and each time we changed the dosage. We trust the doctor doing the med check every three months to tell us if she's not growing enough. My daughter doesn't eat hardly anything after breakfast until suppah time, then she'll eat off and on for about 2-3 hours. her appetite does adjust to meds after a few weeks or so. It is well worth this minor issue compared to before she started medication. She is skinny but not off the charts, very tall also. They get used to the meds, and the appetite increases. I'm guessing it takes 3-4 weeks. Then they eat something, but not as much as without meds. I give a breakfast before meds. Right after school at 2-3pm sometimes they will eat lunch. So "lunch" at school is not really lunch in my mind. I don't ask about lunch, just serve, because if I asked they would say no. If they don't eat much for lunch, I will serve carnation instant breakfast or a protein shake. For dinner, they eat.I am glad to hear from all of you that it gets better after 3-4 weeks, because this has been a concern of mine too. My son seems to be getting better for us, but this part has been frustrating-esp. since he gets in such dark moves when he hasn't eaten.