Concerta and Ritalin both contain methylphenidate for treating Attention Deficit Hyperactivity Disorder. Concerta is extended-release, providing steady symptom control for about 10–12 hours with once-daily dosing. Ritalin is immediate-release, acting quickly but lasting only 3–4 hours, often requiring multiple doses daily. Side effects are similar, including appetite loss, insomnia, and increased heart rate, but dosing schedules and duration differ significantly.