Sounds like a detailed conversation with your difficult child's doctor is in order. After reading your replys, I wanted to mentioned a few things and these are just comments as a Mom to 2 ADD/ADHD difficult child. Any changes to guanfacine and/or Intuniv with my difficult children took 2 weeks to level out.
Intuniv lowers blood pressure, it should not increase blood pressure,
Try dosing Concerta in the AM and Intuniv in the PM,
Intuniv isnt very effective medication for hyperactivity, so maybe an increase to the Concerta is in order (27 mg for age 10 seems low to me),
The generic twice-a-day version of Intuniv (guanfacine) might be easier to manage to get the right dosing level
Again, just a few thoughts from a Mom who has been there... done the medication management challenge!
