Bek, 6 1/2, uses it. She was taking 2 mg before all 3 meals, but as Harriett said, it totally wiped her out. She would get home from school, fall asleep during afternoon treatments, not wake up for dinner until 7:30 or later (with us trying for more than an hour to get her up), then back to sleep during before bed treatments at 8:30. We had her cut back to 2 mg just before dinner. She still naps fter school, but she can wake up easier and earlier.
She had told me that she didn't want to take it anymore because it wasn't working. About 4 months ago, clinic changed it to 2 mg before dinner for 3 weeks, then 1 week off, saying that sometimes it works better by doing that. I really don't see that it's working. She's been on it for about a year now, and has not put on much weight in the last year.
Good luck with it.