My doctor just increased my Concerta dose to 72 mg (maximum allowed) from 54 mg. I asked about taking part of my dose in the morning and the rest at about noon to avoid late afternoon/early evening crash(loss of energy and motivation) as after a few hours Concerta starts tapering off. My doctor said some patients take it that way, we agreed to try 54 mg in morning and 18 mg about 4 hours later. Today is my 4th day of the new split dose,it works so much better for me no afternoon/early evening crash. I have no problems getting to sleep. I’m really surprised there is not more information online of split dosing Concerta. About taking Concerta every 12 hours I did this a few times when called in to work night shift at the last moment, it worked OK but not a substitute for sleep. My 1st post here maybe it will help someone.