Hey, I feel for you and I can't tell you how many posts I have seen like this on the ADHD forum - http://www.medhelp.org/forums/ADD---ADHD/show/175
- where I am also the CL.
First the doctors reply to you about him not having ADHD based solely on, "he has high grades, can sit and read therefore he doesn't have ADHD." Is absolute BS. That is not how you judge ADHD. It does not follow any of the clinical guidelines. I am guessing she is is pediatrician with very limited experience with ADHD. He is 7, if he has any intelligence at all he will do well in school. But by middle school, when things like algebra arise and your innate intelligence can't cope with not being able to pay attention in class - those great grades will disappear. Her main problem is that the clinical guidelines call for a questionnaire to be sent to home and school to see what the people who actually deal with the child see. If that was not done, her opinion is void. Which it is from the experience I have had.
Point being - he may not have ADHD, or he may. But you need to know what is going on. If you don't know the problem, then you can't solve it. If he does have ADHD, there are definite things that you do to deal with his behavior - compared to a child who does not have ADHD. It sounds like you have tried many things (which might be part of the problem), but if what you have tried has not worked. Its kind of silly to keep trying them.
So YES, I can understand why you are going crazy. I have seen many posts just like yours on the ADHD forum.
You need to find a doctor like a psychologist or psychiatrist that specializes in kids. And get the opinion of somebody who knows and understands what ADHD can do to a kid.
By the way, asthma medicines are or can be a real upper to kids depending on the med. It could really be making his condition worse. The inhalers are the worst (depending on the med in the inhaler). You might want to look more into that. Does his condition seem to get worse during any particular time of the year? Or has he been pretty consistent. How was he before he started the medication?
What kind of sleep does he get? Lack of sleep will really mess up a kid. It is really important to deal with that - if it is an issue. Has your doc mentioned any of the last two items to you?
Finally, don't, "spend a large portion of my day saying "the way you are acting is why we aren't (insert whatever activity here)" and he doesn't seem to get that... " Talking to him just will not work. And talking to him when he is having a tantrum - won't work.
The rule is that when he starts a tantrum - he gets a short timeout. And the timeout does not start until the tantrum stops. He will go nuts for a while. Just keep repeating - "as soon as you choose to stop your tantrum, the timeout will start and 2 min later you can ..." Do not try to reason with him or talk with him while he is yelling. You are just playing into his hands.
Essentially, the rules for behavior modification are that there must be immediate, short, consistent consequences. Do not expect overnight miracles. It has taken him awhile to get to this point and it will take a while to relearn control. But he will.
I would also look into buying "Cool down and work through anger" or "When I feel angry". This is part of a series of books aimed at 4 to 7 year olds and meant to be read to them at night (several times) and then practiced. Kids do need to be taught how to deal with anger. You do not try and use these techniques while he is screaming. But once he stops or later on in the day - you can refer back to them or pull the books back out.
You can find them here - http://www.amazon.com/Cool-Through-Anger-Learning-Along/dp/1575423464/ref=pd_sim_b_5
Oh, you might also buy "SOS Help for Parents," by Lynn Clark. It shows how to make a timeout system effective. It will work to some extent with kids with adhd too - but you have to pick and choose what you use it for. If he does have adhd, there are some things you have to ignore.
I hope this helps. I do have lots of links for dealing with kids with ADHD.
Oh, the more exercise he can get, the better for him and you. Get him involved in anything that makes him sweat.