Concerta dose | ADHD Information

Oh, thank you. He takes two 36 mgs in the morning.I am interested in anyone's answers. My daughter has been on 54mg for years. I did not even know there was a 72mg. My eleven year old son has been on various add meds for almost 4 years. He responds well to Concerta, but seems to get used to his dose after a year or so and needs more for the same effect. He is currently at 72mg/day.  Is anyone out there taking more than this? Is this too much? Help...