SODIUM OXYBATE
Clinical safety rating: avoid
Contraindicated (not allowed)
Gamma-hydroxybutyrate (GHB) receptor agonist; modulates GABA-B and GHB receptors, increasing slow-wave sleep and reducing cataplexy.
| Metabolism | Primarily metabolized via the Krebs cycle; minor metabolism via beta-oxidation and dehydrogenation. Less than 5% is metabolized by CYP450 isoenzymes. No active metabolites. |
| Excretion | Primarily renal; >80% of dose excreted as carbon dioxide via expiration, <5% unchanged in urine; minor fecal elimination. |
| Half-life | 0.5–1 hour; clinical context: rapid elimination necessitates multiple nightly doses in narcolepsy. |
| Protein binding | <1% bound; negligible binding to plasma proteins. |
| Volume of Distribution | 0.3–0.5 L/kg; clinical meaning: small Vd indicates limited tissue distribution and largely extracellular fluid. |
| Bioavailability | Oral: 20–30%; extensive first-pass metabolism (hepatic) reduces systemic availability. |
| Onset of Action | Oral: 15–60 minutes; peak plasma conc. at 0.5–2 hours; clinical effect correlates with rapid absorption. |
| Duration of Action | 2.5–4 hours; clinical note: short duration limits use to sleep onset and maintenance in narcolepsy. |
Oral: 4.5 g to 9 g per day divided into two equal doses of 2.25 g to 4.5 g taken at bedtime and again 2.5 to 4 hours later. Maximum single dose: 4.5 g, maximum total daily dose: 9 g.
| Dosage form | SOLUTION |
| Renal impairment | No dose adjustment recommended for mild to moderate renal impairment. Not studied in severe renal impairment (CrCl <30 mL/min) or ESRD; use with caution. For GFR <30 mL/min, consider starting at lower dose (e.g., 3 g/day divided) and titrate slowly. |
| Liver impairment | Child-Pugh A: No adjustment. Child-Pugh B: Reduce starting dose to 50% of standard (e.g., 1.125 g per dose) and titrate cautiously. Child-Pugh C: Contraindicated or not recommended due to lack of data. |
| Pediatric use | Not approved for pediatric use. Off-label dosing for narcolepsy (age >7 years): Starting dose 0.6 g/kg/day divided into two equal doses, titrated to effect; maximum 3 g per dose or 6 g total daily. For GHD: 0.5 g/kg/dose (max 3 g) given once daily at bedtime. |
| Geriatric use | No specific dosing guidelines; use lowest effective dose with caution due to increased risk of falls, cognitive impairment, and renal function decline. Consider starting at 2.25 g per dose (4.5 g/day) and titrate slowly. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
CNS depressants including alcohol can cause profound sedation and respiratory depression Can cause sleepwalking and respiratory depression.
| Breastfeeding | Sodium oxybate is excreted into breast milk. The milk-to-plasma ratio (M/P) is approximately 0.5. Because of the potential for serious adverse reactions in nursing infants, breastfeeding is not recommended during treatment. |
| Teratogenic Risk | Sodium oxybate is classified as Pregnancy Category C. Animal studies have shown adverse fetal effects at high doses, but no adequate human studies exist. First trimester risks include possible neural tube defects; second and third trimester risks include growth retardation and behavioral effects. Use only if benefit outweighs risk. |
■ FDA Black Box Warning
Central nervous system depression: Sodium oxybate is a CNS depressant and can cause respiratory depression, coma, and death when used with alcohol or other CNS depressants. Abuse potential: Sodium oxybate is the sodium salt of gamma-hydroxybutyrate (GHB); abuse or misuse can lead to severe adverse reactions, including seizures, respiratory depression, and dependence. Only available through a restricted Risk Evaluation and Mitigation Strategy (REMS) program.
| Common Effects | excessive daytime sleepiness in narcolepsy |
| Serious Effects |
Hypersensitivity to sodium oxybate; use with alcohol or other CNS depressants; succinic semialdehyde dehydrogenase deficiency; treatment with sedative-hypnotics; history of substance abuse (relative).
| Precautions | CNS depression and respiratory depression, abuse and dependence, seizures, confusion, depression, parasomnias (sleepwalking, sleep-related eating), and impaired ability to drive; alcohol and other CNS depressants increase risk; sodium content (high sodium load); use in renal impairment; nocturnal administration only. |
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| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and respiratory rate. Fetal monitoring (nonstress test or biophysical profile) should be considered in the third trimester. Also monitor for signs of abuse or dependence. |
| Fertility Effects | Sodium oxybate may impair fertility in both males and females. Animal studies have shown reduced fertility and spermatogenesis. In humans, effects are unknown but caution is warranted. |