Atomoxetine is a medication primarily used to treat Attention-Deficit/Hyperactivity Disorder (ADHD) in children and adults. It works by increasing levels of norepinephrine, a neurotransmitter that helps improve focus and attention. Unlike some other ADHD medications, atomoxetine is not a stimulant, which means it has a lower risk of abuse and dependency. Atomoxetine is usually taken once or twice a day and can take several weeks to show its full effects. Common side effects may include stomach upset, fatigue, and changes in appetite. It is important for patients to discuss their medical history with a healthcare provider before starting this medication.