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. While it can be effective for many individuals, it may also cause side effects such as insomnia, decreased appetite, and anxiety. It is important for patients to follow their healthcare provider's instructions when using methylphenidate.