sodium oxybate

(soe-dee-um ox-ee-bate) sodiumoxybate,

Xyrem

(trade name),

gamma hydroxybutyrate (GHB)

(trade name)

Classification

Therapeutic: anticataplectic
Pharmacologic: hydroxybutyrate
Pregnancy Category: B

Indications

Treatment of cataplexy in patients with narcolepsy (generally with concurrent stimulant therapy).

Action

Sodium oxybate is a CNS depressant. Its mechanism of action as an anticataplectic is not known.

Therapeutic effects

Decreased incidence of cataplexy episodes in patients with narcolepsy.

Pharmacokinetics

Absorption: Rapidly but incompletely absorbed (25%) following oral administration; absorption is delayed and decreased by a high fat meal.Distribution: Unknown.Metabolism and Excretion: Undergoes significant first-pass hepatic metabolism. Almost entirely biotransformed to carbon dioxide which is eliminated by expiration; <5% excreted unchanged in urine.Half-life: 30–60 min.

Time/action profile (CNS effects)

ROUTE	ONSET	PEAK	DURATION
PO	rapid	0.5–1 hr	6 hr

Contraindications/Precautions

Contraindicated in: Concurrent alcohol, CNS depressant or sedative/hypnotic therapy.Use Cautiously in: Hepatic impairment (↓ starting dose by 50%); Patients with hypertension, HF or renal impairment (contains 1.6 g sodium/9 g sodium oxybate); Pregnancy (use only if clearly needed); Lactation or children <18 yr (safety not established).

Adverse Reactions/Side Effects

Central nervous system

seizures (life-threatening)
dizziness (most frequent)
headache (most frequent)
somnolence (most frequent)
abnormal dreams
confusion
depression
insomnia
nervousnessweakness

Respiratory

respiratory depression (life-threatening)

Gastrointestinal

nausea (most frequent)
abdominal pain
dyspepsia
vomiting (most frequent)

Genitourinary

urinary incontinence

Musculoskeletal

arthritis
myalgia

Miscellaneous

pain
hyperhidrosis

Interactions

Drug-Drug interaction

↑ CNS depression with other CNS depressants including alcohol and sedative/hypnotics (concurrent use is contraindicated).

Route/Dosage

Oral (Adults) 2.25 g at bedtime, repeated 2.5–4 hr later (total daily dose 4.5g), may be increased at 2 wk intervals by 1.5 g/d(0.75 g/dose) up to 9 g/day.

Hepatic Impairment

Oral (Adults) Decrease starting dose by 50% (1.12 g at bedtime, repeated 2.5–4 hr later (total daily dose 2.25 g; dose increments should be titrated to desired effect with close monitoring.

Availability

Solution for oral administration (in kit with measuring devices): 500 mg/mL in a 180 mL bottle

Nursing implications

Nursing assessment

Assess respiratory status, sleep patterns, and number of cataplexy attacks before starting sodium oxybate. Patients must be monitored at least every 3 mo for effectiveness and side effects.
Lab Test Considerations: May cause ↑ alkaline phosphatase, creatinine, serum bilirubin, AST, ALT, cholesterol, glucose, sodium, and uric acid. May cause hypocalcemia.
- May cause albuminuria and hematuria.

Potential Nursing Diagnoses

Risk for injury (Adverse Reactions)

Implementation

Oral: Administer at bedtime and then 2.5–4 hr later. Prepare both doses prior to bedtime. Dilute each dose with 60 mL of water in child-resistant dosing cups provided prior to ingestion. First dose is administered at bedtime while in bed and the second dose is administered 2.5–4 hr later while sitting in bed. Prepare second dose before administering first dose and place in close proximity to patient's bed.
- Administer on an empty stomach several hours after a meal. Food significantly reduces absorption.
Sodium oxybate is available only through the restricted distribution program (Xyram Success Program) through a single centralized pharmacy.
Non-medical uses of sodium oxybate are listed under the most restrictive schedule of the Controlled Substances Act (Schedule I) due to its abuse potential. Its rapid onset of sedation, coupled with its amnestic effects, make it particularly dangerous for the voluntary and involuntary (assault victim) user.

Patient/Family Teaching

Prescribers must document that patients have read the Xyrem Success Program educational materials before the first prescription will be filled. Review materials with each refill in case of new information. Materials are distributed by a single centralized pharmacy.
Instruct patient to mix and take sodium oxybate on an empty stomach exactly as directed. Medication causes sleep very quickly; advise patients to take only at bedtime while in bed. Time between food and dose should remain consistent. Instruct patient to lie down and sleep after each dose and not to take sodium oxybate at any other time than at night, immediately before bedtime and 2.5–4 hr later. Advise patient to set an alarm clock to wake and take the second dose. If the second dose is missed, skip dose and do not take again until next night. Never take 2 doses at once.
If more than prescribed dose is taken or if taken by accident, get emergency help immediately. Keep out of reach of children.
Caution patient to avoid driving and other activities requiring alertness for 6 hr after taking sodium oxybate. Caution should continue during the next day until response to medication is known.
Inform patient of potential adverse reactions. May cause urinary incontinence. Notify health care professional if incontinence, snoring, trouble breathing during sleep, confusion, abnormal thinking, depression, loss of consciousness, sleepwalking, increased sleepiness during the day occur.
Instruct patient to consult health care professional before taking other Rx, OTC, herbal products, vitamins or supplements.
Caution patient to avoid alcohol or other CNS depressants while taking sodium oxybate.
Advise female patients to notify health care professional if pregnancy is planned or expected or if breastfeeding.
Emphasize the importance of frequent monitoring by prescriber. A detailed account of adverse reactions experienced by the patient will be taken.

Evaluation/Desired Outcomes

Reduced number of cataplexy in patients with narcolepsy.

sodium oxybate

Gamma-hydroxybutyrate, Xyrem^® Neurology A neuropharmacologic used to manage narcolepsy and cataplexy, which causes abrupt loss of muscle control. See Date rape drug.