Xyrem is a prescription medication primarily used to treat narcolepsy, a sleep disorder characterized by excessive daytime sleepiness and sudden sleep attacks. It contains the active ingredient sodium oxybate, which helps improve nighttime sleep and reduce daytime sleepiness in patients with this condition. In addition to its use for narcolepsy, Xyrem is also prescribed to manage cataplexy, a sudden loss of muscle tone often associated with narcolepsy. The medication is taken at night and requires careful dosing, as it is a controlled substance due to its potential for abuse and side effects.