Lack of appetite, poor or delayed sleep, weight loss, increased anxiety, emotional lability are most typical of the side effects. Sometimes these are short-lived and fade over a couple of days as the person adjust to the medication; for us appetite and sleep took a few days to shake out.
Dosing can be very individual. Also, be aware that there will likely be a rebound as the medication wears off. You may see hyper behavior with this, too.