An Open Label Study of FT218 in Subjects With Narcolepsy

Inclusion Criteria: * Subjects receiving a stable doses of twice-nightly sodium oxybate IR or mixed salts oxybate for at least 4 weeks and are willing to switch to FT218 * Subjects who completed the CLFT218-1501 REST-ON Study in a compliant manner and for whom the Investigator determines would receive benefit from treatment with FT218 and have not started treatment with twice nightly sodium oxybate IR or mixed salts oxybate * Are treatment naïve to any oxybate therapy (i.e. FT218, twice nightly sodium oxybate IR or mixed salts oxybate) * Subjects have a diagnosis of narcolepsy, either confirmed prior to the REST-ON study or as confirmed by the Investigator as defined by the International Classification of Sleep Disorders 3 criteria (AASM 2014) * Willing and able to give written informed consent for study participation. Young adults (16 and 17 years old) who have not reached the age of majority must be capable of giving assent in addition to consent from a legally authorized guardian, as required by local laws and regulations. Exclusion Criteria: * Subjects that terminated the CLFT218-1501 REST-ON Study prior to completing Visit 8 * Any use of the following medications during the study: Anticonvulsants, Clonidine, Hypnotics, Anxiolytics, Sedating antihistamines, Antipsychotics, Other experimental medications designed to treat narcolepsy, cataplexy or any other condition, or other medications with significant sedating effects/CNS depressant effects are prohibited for REST-ON and naive patients. Patients on twice nightly sodium oxybate IR on medications in classes listed above may be eligible for enrollment if the subject has been on a stable dose of the prohibited medication in combination with a stable dose of twice nightly sodium oxybate or mixed salts oxybate for at least three months and has demonstrated no AEs, intolerance, or interactions AND is approved to participate by the Medical Monitor. Sedative hypnotics are prohibited regardless.) * A diagnosis of sleep apnea where AHI is ≥15 and/or current use of CPAP or other devices for sleep apnea.