How does Xyrem work for narcolepsy?

Xyrem's mechanism of action for narcolepsy is thought to involve binding to GABA_B and GHB receptors which enhances delta wave activity, improving the quality and quantity of deep sleep; however, the exact way it works is unknown. By taking Xyrem at night, the quality and quantity of deep sleep is improved, which reduces the number of sleeping periods during the day. This improves the symptoms of narcolepsy.

Narcolepsy is a sleep disorder that is characterized by excessive daytime sleepiness. Xyrem (sodium oxybate) is the sodium salt of gamma-hydroxybutyrate (GHB) which is a central nervous system (CNS) depressant. CNS depressants slow down brain activity, which makes them useful for treating sleep disorders. Once in the body, Xyrem is metabolized to a neurotransmitter called GABA which has the potential to bind to receptors such as GABA_B and GHB that slow down brain activity, such as enhancing delta waves (a type of high amplitude brain wave generally associated with slow-wave sleep) during the third stage of sleep.