Out of control | ADHD Information

I have an 8 year son, who is diagnosed with adhd and anxiety. He is so unpredictable. He has outbursts of rage and violence and there is no way of calming him down. He constantly provokes his little sisters and swears at them. I am at my wits ends of what to do with him. When he flips out i try and remove him from others but it is very hard as he keeps on coming out of his room kicking and screaming abuse. It is like walking on egg shells with him as he can be perfectly happy one minute and in a rage int he next, and then afterwards  he is like nothing ever happened. Any advice?? I so need help in what to do, we are looking into medication too. Medication is a help but a good behavior plan will go farther.  Here is an idea for you  do you know what calms him down?  Make an angry box out of a shoe box so when he gets angry he can go to it and take something out of it to do but only when angry.  Then when calm have him apologize for behavior or make an I am sorry card and have a teaching moment with him.  Have him practice how he should behave with his siblings and if he continues to upset them pull a privilage for time out and he has to earn it back by doing an extra chore or by good behavior.  Also maybe counseling may help as well, good luck.   Jill