The US Food and Drug Administration (FDA) has approved Onyda XR (clonidine hydrochloride) for the treatment of attention-deficit/hyperactivity disorder (ADHD), drug manufacturer Tris Pharma announced in a statement. The drug is the first approved liquid nonstimulant ADHD medication. The once-daily extended-release oral suspension, with nighttime dosing, can be used alone or as an adjunctive therapy to FDA-approved stimulant medications in pediatric patients aged 6 years or older.