sodium oxybate extended-release

General Information

Sodium oxybate extended-release (Lumryz) is a once-nightly oxybate product indicated for cataplexy or excessive daytime sleepiness (EDS) in patients 7 years of age and older with narcolepsy (label).

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

The key practical differentiator is dosing: Lumryz is once nightly, so it can avoid a planned middle-of-the-night second dose required by immediate-release sodium oxybate. This can reduce sleep disruption and adherence burden for some patients (label/clinical).

Alcohol is contraindicated. The extended-release formulation has an alcohol-associated dose-dumping signal that can increase early drug release and raise respiratory risk (label).

The Lumryz compare view, evidence feed, and print page support review of oxybate formulations and alternatives.

Once-nightly dosing can improve feasibility versus split-night oxybate, but REMS requirements, strict avoidance of alcohol/sedatives, and safe storage remain central implementation constraints. Sodium burden can also matter for patients with hypertension, heart failure, or kidney disease (label/clinical).

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 sedation can occur quickly after dosing, safety planning prioritizes taking the dose while in bed and avoiding hazardous activities after dosing (label/clinical).

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

Metabolism and 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; dosing is separated from meals (label).

Dosing and Administration

• Adults: start 4.5 g once per night. Increase by 1.5 g per night at weekly intervals to a recommended range of 6–9 g once nightly; doses higher than 9 g per night have not been studied and should not ordinarily be administered (label).
• Pediatric patients 7 years and older: dosing is weight-based with maximum total nightly doses by weight band (label).
• Patients treated with immediate-release sodium oxybate can be switched to Lumryz at the nearest equivalent total nightly dose in grams (label).
• Mix the packet with water before administration; take the dose while in bed due to rapid sedation and fall risk (label/clinical).
• Alcohol is contraindicated due to dose dumping risk with the extended-release formulation (label).

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).
• Mood and neuropsychiatric symptom monitoring (label/clinical).
• Hepatic impairment assessment and appropriateness of initiation (label).

Adverse Effects

Interactions

• Alcohol is contraindicated. Sedative-hypnotics and other CNS depressants are generally avoided due to additive CNS depression and respiratory depression risk (label).
• Divalproex/valproate produces a modest exposure increase, but sedating pharmacodynamic interactions are still a concern; monitor closely if co-prescribed (label/clinical).
• Opioids and benzodiazepines increase respiratory risk; when such agents are required, clinicians often reassess whether an oxybate product is appropriate (clinical).

Other Useful Information

• Sodium burden can be clinically relevant at higher doses; review overall dietary sodium and comorbid cardiovascular disease when selecting between oxybate formulations (label/clinical).
• Once-nightly dosing can improve feasibility for patients who cannot reliably wake for a second dose or for whom split-night dosing worsens sleep fragmentation (clinical).
• Implementation topics (REMS enrollment, mixing instructions, safe storage, and avoidance of alcohol/sedatives) are reviewed explicitly at initiation and during titration (label/clinical).

References

1. Lumryz (sodium Oxybate) FOR Extended Release Oral Suspension Prescribing Information — DailyMed (2025)
2. Treatment of central disorders of hypersomnolence: an American Academy of Sleep Medicine clinical practice guideline — Journal of Clinical Sleep Medicine (2021)
3. Treatment OF Central Disorders OF Hypersomnolence: AN American Academy OF Sleep Medicine Systematic Review, Meta Analysis, AND Grade Assessment — Journal of Clinical Sleep Medicine (2021)
4. Once Nightly Sodium Oxybate (ft218) Demonstrated Improvement OF Symptoms IN A Phase 3 Randomized Clinical Trial IN Patients With Narcolepsy — Sleep (2021)