In an earlier post I think you mentioned that his teacher at school says he's fine-- nothing unusual in his behavior.
I think you also mentioned that he is fine around other people, including his grandparents-- and its just at home that he is having trouble.
One of the criteria used to diagnose ADHD is that a child must display the problems in at least two settings-- such as home and school, or daycare and home-- or something like that. If I am reading what you wrote properly, your child only displays problems at home.
If that is the case, then it would seem to me that the ADHD diagnosis needs to be revisisted.
If he is behaving with such violence and anger, I would suggest that you seek the help of a child psychiatrist for another diagnosis-- to determine what the root cause of his behavior issues are.