Hi Covebeach....if your child is experiencing rebound, call the doctor as the dose may have to be adjusted. He will continue to experience rebound as the dose is either high or too low. Once the proper dosage is achieved you shouldnt see rebound. For whatever the reason, please call your doctor so that he can monitor and adjust the medication. Dosage is not determined by height or weight as its all very individulistic with stimulant drugs. Below is a link that will answer many of your questions and concerns.
Evidence-based Medication Management for Children and Adolescents with AD/HD - CHADD Fact Sheet #3
My 9 year old also just started Ritalin LA (long acting) this week. The first day we experienced the same type of behavior as you. My son was emotional and violent. He was throwing things and not acting like himself. The next couple of days were better. I don't think the difference is in the longevity. I believe this effect wears off after a while. What dose is your son on? My son weights 105 and is on 20 mg. I actually don't see any change in him and think we might up the dosage. I would suggest you give it another few days and it is likely that this rebound effect will subside. If not, then Ritalin might not be the med for him. Have you seen a change in his behavior? Good luck to you.
My 8 year old son was recently diagnosed with ADHD and put on Ritalin. Initially the Ritalin seemed to work well, but my son became violent several times just as the Ritalin was wearing off. He had never been violent in his life, and we were shocked and confused by his extreme behavior. Eventually his psychiatrist diagnosed something called "Ritalin rebound". Has anyone encountered Ritalin rebound? Can it be overcome by longer-acting forms of Ritalin? Also, if a child has experienced a rebound effect on one drug, does it increase the likelihood he'll experience on another?
Thanks!