Intuniv is a medication used to treat attention deficit hyperactivity disorder (ADHD) in children. Intuniv, known under the generic name guanfacine extended-release tablets act over a long period of time to help control ADHD symptoms and promote better self-control, focus, and ability to sit still. Intuniv is generally used as part of a larger treatment plan, including therapy, to manage ADHD symptoms in children. It's thought that Intuniv impacts the area of the brain that is responsible for impulsive behaviors and attention. Intuniv side effects may include digestive problems (nausea, vomiting, constipation), stomachache and headache, dryness of the mouth, and irritability.