How do I get my sons attention?

My 6-year old son was diagnosed with ADHD in May of this year.  His doctor prescribed Adderall 10mg once daily.  I seemed to be working good until recently.  I talked to his teacher and I have the same issue, trying to get his attention to give him even simple directions is almost impossible.  He is so easily distracted by the simplest things.  Such as a scrape on his knee, or a question or comment he just has to announce.  He can't accept directions until his issue is addressed.  He frequently, almost always interrupts when you try to explain simple direction.  I was against medication at first because I didn't want him to be (droned out) and lose his spunk.  Being on such a low dose this didn't happen.  But I am afraid we will need to up his meds to obtain the effect that we desire.  I wanted to know if anyone has any other suggestions on how to get his attention.

 Thanks in advance for your time!