freddie8605 hit the nail on the head. He could be bipolar, but it could also be caused by stopping the medication. I was put on an anti-psychotic to help assist my anti-depressant, and when I abruptly stopped taking it I went all sorts of weird (and that was with just two weeks of taking it). I was happy and angry at the same time, couldn't sleep properly, just really didn't give two about anything around me or about how my actions were affecting others.
He should see a psychiatrist if he isn't already, and be monitored to see whether it's the medication or bipolar disorder beginning to show itself. Either way, the psychiatrist could help him find a medication that works better for him, and help him better understand what's happening with his mood and actions right now.
Its possible but it could also be caused by stopping the medication to quickly - called withdraws. i would suggest to him about seeing his doctor do what ever you can to get him there and go with him and suggest your concerns.
Best of luck
yep sounds like it to me. I personally have bi polar. I get mad at the littlest things and i dont just take it out on one person i take it out on everybody that crosses my path. its all about routine nothing can be changed it will throw him off. if that medicine makes him sick ask doctor for a different one. I am currently taking trileptal a seizure med for bipolar. good luck