This problem is adapted from the textbook section 2.3) Adderall is a proprietary combination 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(7) with 7.7% of the drug being removed from the blood each hour.