This is only from my experience, so please take it for that. :o) We all have such different feelings on so much. :o))
My son wasn't talking at 3. (my ds was babbling up until the time he got his MMR vaccine, and then it went away) When he was 2 we took him to a developmental psychiatrist to see if he might be autistic. He is not... because of the speech issues, you might call him PDD-NOS, but he doesn't even really qualify for that. Out of 30 symptoms my dr. looked for to diagnose ADHD, she could identify 30 and more.
So, my ds has been on the medication since his 3rd birthday (highly unusualy). I would do several things if your son is newly on medication. 1.) I would request a cardiologist referral. Stimulants are a FDA "Black box drug." Which not to scare you because it is very very rare... but they have been found to cause cardiac problems and heart attacks and strokes in children who take them. The vast majority of the deaths have been to children with (usually undiagnosed) cardiac issues. For your peace of mind, I would go and let them do an echo (u/s of the heart... non invasive) and just make sure there is nothing there that could raise your ds's risk.
2.) I would also enroll him in Occupational Therapy. ADHD goes right along with it. THey find ways to help control it on their own. It probably won't get him to where he doesn't need the medication (especially at first) but it will compliment the medication well. I really believe that we could ALL use OT. lol.
3.) FInd someone at the school, who's opinion you trust. We have mainly had very good teachers. However, there are some teachers out there, and we have had 1 of them, that don't care how drugged their kids are... as long as they are easier to deal with. You need someone at school with your ds who can call and say... "You know, he seems a little like a zombie. Cut back." You want your ds to be able to sit still... not to be unable to do anything but sit still. It will take time to find a perfect dose without side effects.
4.) Monitor his sleep. The drugs are stimulants and can keep the kids who take them awake. It could make your ds have a difficult time sleeping and then have nightmares when he does. Obviously a sleepy child, can not perform his best.
5.) Realize, that with the ADHD, he already feels "differently" then most of his friends. Be very careful with his spirit. (This comes from the mommy in me.) You want to make him do the right things. I am very strict with my ds.... BUT, these kids are just a tiny bit different... and you want to guard his little heart. If he is telling you that he is having a hard time... look into tutoring, or work extra hard at home, or find something that can help. I would also say just don't let your teacher just nag at him. Tell her to get in touch with you and you can deal with any issues. Sometimes, because the kids are up and down and moving around... teachers will just keep calling them out. OVER AND OVER AND OVER. which is hard to deal with for any child... especially for ours.
6.) Im guessing eating will become an issue for you, after a few months on the meds. I have two words: ENSURE PLUS!! My ds is just never hungry on the meds. I can get him to drink 2 of the Ensure Plus drinks a day and then not have to fight him so hard to eat. I know he is getting enough vitamins and minerals... and so if I can only get him to eat Pizza.... so be it. We feed him whenever he wants and whatever he wants. lol.
Anyway... I am pretty sure you were not hoping for all of this. Im sorry. It was just really hard to start medicating my ds too. So I kind of have a list of things in my head that bothered me and that we had to work through. lol.
HUGS!!