Definitely only see a child psychiatrist specialized in treating ADHD. We are happy with Dr. Hemanth in Rockville.
Do a little research into drug categories, OP. Stimulants are by far the safest and best-known. Then there are the others.
11 year DS with severe ADHD takes 20mg of Focalin XR (extended release). The extended release is important because it ensures that about half of the dose is activated at around midday instead of immediately when taken in the morning, and lasts through the afternoon. Appetite usually decreases, but it's very important to eat so that the whole dose is not metabolized in the morning.