Hey SWW,
I can think of no ADD medication used for children that is not also used for adults. Concerta is a good choice to try next. If it works, but you can't get the dosage right, talk to your doctor about trying the short acting stimulant Ritalin. Sometimes it's necessary to try three or more stimulants before finding the right one. It's a real drag, I know. Been there myself. In general, if Dexedrine or Adderall don't work, Concerta or Ritalin sometimes will. The reverse is true too.
Winnie, an adult ADD advocate