Xywav (calcium oxybate/magnesium oxybate/potassium oxybate/sodium oxybate) is a fixed-dose combination medication used to treat cataplexy or excessive daytime sleepiness. It contains a mixture of the oxybate salts calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate. It is a central nervous system (CNS) depressant and it is taken by mouth.
It is manufactured by Jazz Pharmaceuticals and was approved for medical use in the United States in July 2020.
Xywav is indicated for the treatment of cataplexy or excessive daytime sleepiness in people aged seven years of age and older with narcolepsy; and for idiopathic hypersomnia.
Xywav is recommended to be dosed twice nightly in narcolepsy and idiopathic hypersomnia (â¤9g total), with an additional option for once nightly dosing in idiopathic hypersomnia (â¤6g).
In September 2025, Jazz Pharmaceuticals presented data from an open-label study evaluating higher doses of Xywav in narcoleptic patients; the analysis reported that doses of 9-12 g nightly were associated with additional improvements in excessive daytime sleepiness and cataplexy frequency compared with the currently approved maximum dose of â¤9 g.
Xywav is composed of 46.8% calcium, 26% potassium, 19.2% magnesium, and 8% sodium oxybate by weight in an oral solution. The concentration of oxybate salts in solution is 0.5 g/ml, equivalent to .413 grams of total oxybate.
The US Food and Drug Administration label for Xywav contains a boxed warning for central nervous system depression, abuse, and misuse.
Slowed breathing, trouble breathing, sleep apnea.
Confusion, hallucination, unusual or disturbing thoughts (abnormal thinking), anxiety, depression, suicidal thoughts or actions, increased tiredness, feelings of guilt or worthlessness, and difficulty concentrating.
Xywav was granted orphan drug designation by the US Food and Drug Administration.
Xywav is a prescription drug and a Schedule III controlled substance in the United States.
In the testing phase of the drug, it was known as JZP-258.
Calcium, magnesium, potassium, and sodium oxybate are salts of gamma hydroxybutyrate (GHB).