Selegiline, a monoamine oxidase (MAO) inhibitor, is FDA-approved as an adjunct treatment in the management of patients with Parkinson disease and as a treatment for a major depressive disorder (MDD) in adults. Selegiline is also used off-label for early Parkinson disease and the treatment of attention-deficit/hyperactivity disorder (ADHD). This activity outlines the indications, mechanism of action, methods of administration, significant adverse effects, contraindications, and monitoring, of…