The present disclosure provides oral drug dosage forms comprising: (a) an erodible non-stimulant material admixed with an ADHD non-stimulant; and (b) an erodible stimulant material admixed with an ADHD stimulant, wherein the erodible non-stimulant material admixed with the ADHD non-stimulant is embedded in a substrate material, and wherein upon exposure to gastrointestinal fluid the ADHD non-stimulant is released according to a desired non-stimulant release profile and the ADHD stimulant is released according to a desired stimulant release profile. In some embodiment, the ADHD non-stimulant is released according to a sustained release profile. In some embodiments, the ADHD stimulant is released according to an immediate release profile. The oral drug dosage forms of the present disclosure are useful for the treatment of attention deficit hyperactivity disorder (ADHD). Also provided herein are methods of designing and manufacturing the oral drug dosage forms described herein.