Methylphenidate is a prescription medication commonly used to treat attention deficit hyperactivity disorder (ADHD) and narcolepsy. It works by increasing the levels of certain chemicals in the brain that help improve focus, attention, and impulse control. This medication is available in various forms, including tablets and extended-release capsules. It is important for patients to follow their doctor's instructions regarding dosage and usage to minimize potential side effects, which can include insomnia, decreased appetite, and increased heart rate. Regular monitoring by a healthcare professional is recommended during treatment.