Atomoxetine is a selective norepinephrine inhibitor. By enhancing the activities of norepinephrine in certain areas of the brain, atomoxetine reduces chemical imbalances that are believed to contribute to ADHD symptoms.

Before atomoxetine was approved by the FDA in 2002, all the drugs previously approved for ADHD were stimulants. Stimulants such as amphetamines have the potential to be abused and are sometimes sold illegally.

Atomoxetine should not be used with certain types of antidepressants known as monoamine oxidase (MAO) inhibitors since this combination may cause blood pressure and heart rates to increase sharply.

Patients with a history of narrow angle glaucoma should not take atomoxetine. Since the liver breaks down the drug, patients with a history of liver disease should only be prescribed a low dose.

Atomoxetine may cause changes in heart rate or blood pressure. As a result, this drug may not be appropriate for patients that have high blood pressure, rapid heartbeats, heart disease, or a history of strokes.