concerta

methylphenidate + st. john's wort

Methylphenidate inhibits dopamine and norepinephrine reuptake and modestly affects serotonin signaling. St. John's Wort adds reuptake inhibition of serotonin, dopamine, and norepinephrine, plus weak MAO inhibition. Combination risks serotonin syndrome and a published case series suggests reduced methylphenidate efficacy for ADHD.