This problem is adapted from section 2 3 of Neuhauser and Roper Adderall is a proprietary combi mation of amphetamine salts that is used to treat ADHD Attention Deficit Hyperactivity Disorder The patient takes one pill before 8am and the drug has completely entered the bloodstream by 8am At 8am the blood concentration of the drug is 33 8 ng ml Adderall has first order elimination kinetics 8 with 7 7 of the drug being removed from the blood each hour