Mixed-salt oxybates

XYWAV

What it isMixed-salt GHB and GABA-B agonist (XYWAV, 2020); narcolepsy with cataplexy or sleepiness, and idiopathic hypersomnia.

Why this oneIt contains ~92% less sodium than Xyrem and is the only drug approved for idiopathic hypersomnia (2021).

What limits itProfound CNS and respiratory depression makes alcohol, sedatives, and unsupervised access dangerous; dispensing is restricted.

FDA-approved for

BOXED WARNING CNS depression; abuse and misuse (XYWAV and XYREM REMS)

FDA dosing	Population	Start	Target	Max
Cataplexy or excessive daytime sleepiness in narcolepsy	Adults	4.5 g/night divided into two nightly doses	6–9 g/night	9 g/night
Cataplexy or excessive daytime sleepiness in narcolepsy	Pediatric 7+ y	Weight-based, divided into two nightly doses		Weight-based (≥45 kg: 9 g/night)
Idiopathic hypersomnia	Adults	≤4.5 g/night divided (twice nightly) or ≤3 g (once nightly)		9 g/night (twice nightly) / 6 g (once nightly)

Titration Increase by ≤1.5 g/night per week

Renal Undefined

Hepatic Reduce starting dose by one-half

Doses >9 g/night or single doses >6 g have not been studied

Take at least 2 h after eating
Dilute each dose with ~1/4 cup (60 mL) water; take in bed and lie down immediately
First dose at bedtime, second dose 2.5–4 h later
Prepared doses must be consumed within 24 h