Interindividual and Intraindividual Variation of Methylphenidate Concentrations in Serum and Saliva of Patients With Attention-Deficit/Hyperactivity Disorder.

Background: Therapeutic drug monitoring is becoming increasingly important in psychiatric therapy, especially in children. However, for several reasons, it cannot yet be implemented as a daily routine in clinical or outpatient settings. To evaluate new, noninvasive procedures, blood and saliva (oral fluid) samples were collected from patients with attention-deficit/hyperactivity disorder (ADHD) who were also being administered methylphenidate (MPH).