My son's on Risperdal which helps him at least in some ways...

Having ADHD makes all impulses run through your brain much too fast. You react before you get the chance to think it through... yu act in an instant.
When it comes to my son... he's been very violent.... which is much better with Risperdal... although he's still got times when the impulses hits through the medication filter.

His language can be absolutely horrible... that is something the med is not working on. He blurts it out and they say he probably has tourettes as well.

There are a few things you can try when your son is beginning to act out... *boxing on a punch bag... *go out for a walk... *have his "safe haven"- a part of his room or another room that's only his and where he can learn to go when things get too much.... it should have things calming him down... things that he's interested in...*distraction (if the tantrum isn't all too bad already...
there are many more things to try...

My thoughts are with you and your kids!