Medication absorption after Gastric Byp?

I had gastric byp in 2003, for the last few years I have needed to take medicine for adult ADD. Time release is out of the question, but I was wondering if anyone else has had this problem also, the medications that come in tablet form are supposed to last 4 hrs usually taking them twice a day should work, but I am lucky if they last 2 hrs for me, anyone take any medicine like this and have any luck with it. I have tried the Daytrana Patch and it gave me a rash, I am on Focalin now, 5mg twice a day but like I said I only get about 2-3 hrs out of both doses, any suggestions?