Treating attention deficit hyperactivity disorder (ADHD). It is also used to treat a type of sleep disorder (narcolepsy). It is also used on short-term basis (a few weeks) in combination with other treatments to treat obesity. It may also be used for other conditions as determined by your doctor. Evekeo is a central nervous system stimulant. Exactly how it works is not known. It affects certain chemicals in the brain, which may help to improve attention span and behavior.