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sodium oxybate

Adjunctive therapy

Brand: Xyrem

Published 2026-02-15 · Last reviewed 2026-02-22 · 4 references

Content sourced from FDA labeling (DailyMed) and peer-reviewed literature.

Print sheet Review evidence

At a glance

Class: Adjunctive therapy·Typical dose: Adults: start 4.5 g per night in two doses (2.25 g at bedtime and 2.25 g 2.5–4 hours later). Titrate by 1.5 g per night at weekly intervals to an effective range of 6–9 g per night; doses above 9 g are not ordinarily administered (label).·Half-life: Single-dose range 0.5–1 h·LAI available: No

Class: Adjunctive therapy
Typical dose: Adults: start 4.5 g per night in two doses (2.25 g at bedtime and 2.25 g 2.5–4 hours later). Titrate by 1.5 g per night at weekly intervals to an effective range of 6–9 g per night; doses above 9 g are not ordinarily administered (label).
Half-life: Single-dose range 0.5–1 h
LAI available: No

Quick answers

What is sodium oxybate?: Sodium oxybate (brand Xyrem) is a nighttime medication indicated for cataplexy or excessive daytime sleepiness (EDS) in patients 7 years of age and older with narcolepsy (label).
What is Xyrem?: Xyrem is a brand name for sodium oxybate.
What is Xyrem (sodium oxybate) used for?: Label indications include: Treatment of cataplexy or excessive daytime sleepiness (EDS) in patients 7 years of age and older with narcolepsy; REMS-restricted (label).
What drug class is Xyrem (sodium oxybate)?: Oxybate (Narcolepsy).
What is the mechanism of action of Xyrem (sodium oxybate)?: Nighttime CNS depressant (sodium oxybate; oxybate/GHB) indicated for cataplexy and excessive daytime sleepiness in narcolepsy (patients 7+); Schedule III with boxed warning for CNS depression and abuse/misuse, and dispensed under a REMS due to risk of respiratory depression and misuse.
What strengths does Xyrem (sodium oxybate) come in?: Oral solution: 0.5 g/mL (label).

General information

Sodium oxybate (Xyrem) is a nighttime medication indicated for cataplexy or excessive daytime sleepiness (EDS) in patients 7 years of age and older with narcolepsy (label).

It is a CNS depressant and a Schedule III controlled substance with a boxed warning for CNS depression and abuse/misuse; it is dispensed only through a REMS due to risk of respiratory depression and misuse (label).

Dosing is split into two doses each night (bedtime and 2.5 to 4 hours later). Many patients fall asleep quickly after dosing, so fall risk, safe storage, and nighttime environment planning are core counseling topics (label/clinical).

Alcohol and sedatives increase respiratory depression risk and are generally avoided; interaction review is especially important in polypharmacy and in patients with substance use disorders (label/clinical).

The sodium oxybate compare view, evidence feed, and print page support review of wake-promoting strategies and implementation constraints.

U.S. approvals

Cataplexy in narcolepsy (patients 7 years and older) (2002)
Excessive daytime sleepiness in narcolepsy (patients 7 years and older) (2002)

Formulations & strengths

Oral solution: 0.5 g/mL (label).

Generic availability

Not available generically (brand-only formulation under REMS).

Sodium oxybate can meaningfully improve cataplexy and daytime sleepiness in narcolepsy, but implementation burden (split-night dosing, REMS, avoidance of alcohol/sedatives, safe storage) often determines feasibility in practice (label/clinical).

View labelExact

Mechanism of action

Refer to the Glossary entry on Neurotransmitters for background on receptor systems involved in serious mental illness.

Oxybate (GHB) is a CNS depressant. Clinical framing emphasizes nighttime consolidation of sleep and downstream improvements in cataplexy and EDS when titrated to an effective dose (label/clinical).

Because of abrupt sleep onset after dosing, safety planning focuses on taking doses while in bed and avoiding hazardous activities after dosing (label/clinical).

CNS depressant (oxybate/GHB; mechanism related to sleep consolidation).

Metabolism & pharmacokinetics

Clearance is almost entirely by biotransformation to carbon dioxide, which is eliminated by expiration; <5% of unchanged drug appears in urine within 6 to 8 hours after dosing (label).
Elimination half-life is ~0.5–1 hour; hepatic impairment prolongs half-life and increases exposure (label).
Food reduces absorption; administration is separated from meals (first dose at least 2 hours after eating) (label).

Dosing & administration

Adults: start 4.5 g per night in two doses (2.25 g at bedtime and 2.25 g 2.5–4 hours later). Titrate by 1.5 g per night at weekly intervals to an effective range of 6–9 g per night; doses above 9 g are not ordinarily administered (label).
Prepare both doses before bedtime and dilute each dose with water in pharmacy-provided containers; take the second dose 2.5–4 hours after the first (label).
Take the first dose at least 2 hours after eating; the second dose is taken 2.5–4 hours after the first dose (label).
Patients often fall asleep within minutes after dosing; dosing is taken while in bed and staying in bed after dosing is emphasized to reduce fall risk (label/clinical).

Monitoring & labs

Respiratory risk and CNS depressant co-medication review (label/clinical).
Safe storage and misuse/diversion monitoring consistent with REMS (label/clinical).
Nighttime fall risk assessment and environment planning (clinical).
Hepatic impairment assessment for dosing and safety (label).
Review of interaction with divalproex/valproate if co-prescribed (label/clinical).

Adverse effects

FDA boxed warnings

CNS depression and respiratory depression risk; abuse and misuse risk (boxed warning; label).

Common side effects (≥10%)

Nausea: Common; assess timing and hydration (clinical).
Dizziness: Can contribute to falls, especially at night (label/clinical).
Enuresis: Can occur; sleep disruption and planning may be needed (clinical).
Somnolence: Expected pharmacologic effect; counseling focuses on safe nighttime routines (label/clinical).

Other notable effects

Falls and injuries can occur due to rapid sleep onset or confusion; safe nighttime environment planning and avoiding other sedatives reduces risk (label/clinical).
Misuse/diversion risk is addressed through REMS, safe storage, and monitoring, especially in substance use disorders (label/clinical).
Hepatic impairment increases exposure; lower starting doses are used and monitoring is emphasized (label).

Interactions

Alcohol and sedative-hypnotics are generally avoided due to additive CNS depression and respiratory depression risk (label).
Concomitant divalproex/valproate increases exposure; an initial dose reduction of at least 20% is recommended with close monitoring (label).
Other CNS depressants (benzodiazepines, opioids, some antipsychotics, sedating antidepressants) can increase sedation and respiratory risk; careful review is a routine safety step (label/clinical).

Other useful information

Evidence syntheses and guidelines support oxybate for narcolepsy symptom control, but implementation constraints (split dosing, REMS, sedation risk) often determine feasibility (AASM/clinical).
In serious mental illness, clinicians often coordinate dosing plans with co-medications, housing stability, and safety supports to reduce fall risk and ensure adherence (clinical).

References

Related hubs:SMI toolkit·Support resources