Xywav is used to treat cataplexy (sudden loss of muscle strength) or to reduce excessive daytime sleepiness caused by narcolepsy. Xywav is also used in adults to treat idiopathic hypersomnia (IH)  which is an uncommon chronic sleep disorder that causes daytime sleepiness even after a good night's sleep.

Xywav is a central nervous system depressant. Xywav is an oral solution containing a combination of calcium oxybate, potassium oxybate, magnesium oxybate and sodium oxybate. Xywav is a low-sodium alternative to Xyrem.

Xywav contains an ingredient also known as GHB, a known street drug of abuse. Because of the potential for abuse and serious side effects, Xywav is available only from a certified pharmacy under a special program (XYREM REMS). You must be registered in the program and understand the risks and benefits of this medicine.

Who can use Xywav?

Xywav is FDA-approved to treat:

• treatment of cataplexy or excessive daytime sleepiness (EDS) in patients 7 years of age and older with narcolepsy.
• treatment of idiopathic hypersomnia (IH) in adults.

Is Xywav a controlled substance?

Yes, Xywav is a Schedule III controlled substance (CIII) when used legitimately. It is considered a Schedule I controlled substance when used illicitly and is subject to Schedule I penalties. The active ingredient of Xywav is a form of gammahydroxybutyrate (GHB). Abuse of illegal GHB, either alone or with other CNS depressants, may cause serious medical problems.

Xywav can cause severe drowsiness and can slow or stop your breathing, even at regular doses or if you are also taking stimulant medicines. You should not do anything that requires you to be fully awake or is dangerous, including driving a car, using heavy machinery, or flying an airplane, for at least 6 hours after taking Xywav. Those activities should not be done until you know how Xywav affects you or your child.

Fatal side effects can occur if you take Xywav with: alcohol, other sleep medicines, or other drugs that cause drowsiness or slow your breathing.

Misuse of Xywav can cause breathing problems, seizure, loss of consciousness, or death. Keep the medication in a place where others cannot get to it.

Xywav may be habit-forming. Misuse can cause addiction, overdose, or death. Keep the medication in a place where others cannot get to it.

Take Xywav exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Xywav can cause severe drowsiness and can slow or stop your breathing, even at regular doses or if you are also taking stimulant medicine.

Xywav may be habit-forming. Misuse can cause addiction, overdose, or death. Keep the medication in a place where others cannot get to it. Selling or giving away this medicine is against the law. Do not allow anyone else to use this medicine.

Xywav instructions

Wait at least 2 hours after eating before taking or giving Xywav.

Xywav is taken as 1 nightly dose, or as 2 doses (once at bedtime and again 2.5 to 4 hours later). 

Xywav must be mixed with 2 ounces (1/4 cup) of water in the child-resistant dosing cups provided with the medication.

If you take 2 nightly doses, prepare both doses while you are getting ready for bed. Place the second dose in a secure location next to your bed so you can take it without getting up. You may need to set an alarm to awaken for the second dose.

This medicine works quickly. Most people fall asleep within 5 to 15 minutes.

Take Xywav only while you are sitting in bed ready for sleep. Some people have fallen asleep while standing or getting up from bed, which has caused injuries serious enough to need treatment in a hospital.

Do not allow a child to use this medicine without adult supervision.

Do not change your dose or stop using Xywav suddenly, or you could have unpleasant withdrawal symptoms. Ask your doctor how to stop using this medicine safely.

Store at room temperature, away from moisture and heat. Keep your medicine in a place where no one can use it improperly.

Throw away any dose not used within 24 hours after mixing.

Do not keep leftover Xywav liquid. Ask your pharmacist where to locate a drug take-back disposal program. If there is no take-back program, pour any unused liquid medicine down a sink drain.

Usual Adult Dose of Xywav for Narcolepsy

Initial dose: 4.5 g orally per day, divided and given as 2 equal doses of up to 2.25 g/dose

Maintenance dose: The dose may be increased by 1.5 g (OR 0.75 g/dose) orally per night in weekly intervals up to 6 to 9 g/day.

Maximum dose: 9 g/day

Comments:

• Both doses should be diluted at the same time at night.
• The first dose should be taken at bedtime and the other dose should be taken between 2.5 to 4 hours after; some may need to set an alarm to awaken to take the second dose.
• Patients should remain in bed after taking each dose.
• If the second dose is missed, patients should skip the dose and should not take this drug until the next night.
• Dosing may be gradually titrated, and doses should be determined by efficacy and tolerability.

Use: Treatment of cataplexy (excessive daytime sleepiness) in patients with narcolepsy

Usual Adult Dose of Xywav for Idiopathic Hypersomnia

Two times a night regimen:

Initial dose: 4.5 g orally per day, divided and given as 2 equal doses

The dose may be increased by 1.5 g (OR 0.75 g/dose) orally per night in weekly intervals

Maintenance dose: 6 to 9 g/day

Maximum dose: 9 g/day

Once a night regimen:

Initial dose: 3 g orally per day, divided and given as 2 equal doses

The dose may be increased by 1.5 g (OR 0.75 g/dose) orally per night in weekly intervals

Maintenance dose: 3 to 6 g/day

Maximum dose: 6 g/day

Comments:

• This drug may be given in divided doses or as a single dose.
• Dosing may be gradually titrated, and doses should be determined by efficacy and tolerability.
• Patients may respond better with the first dose given at bedtime and the second dose given between 2.5 to 4 hours later.

Use: Treatment of idiopathic hypersomnia

Usual Pediatric Dose for Narcolepsy (7 years and older)

Less than 20 kg:

Specific dosing recommendations are not available.

20 to less than 30 kg:

Initial dose: Up to 2 g orally per day, divided and given as 2 equal doses of up to 1 g/dose

Maintenance dose: The dose may be increased by 1 g (OR 0.5 g/dose) orally per night at 1 to 2-week intervals up to 6 g/day.

Maximum dose: 6 g/day

30 to less than 45 kg:

Initial dose: Up to 3 g orally per day, divided and given as 2 equal doses of up to 1.5 g/dose

Maintenance dose: The dose may be increased by 1 g (OR 0.5 g/dose) orally per night at 1 to 2-week intervals up to 7.5 g/day.

Maximum dose: 7.5 g/day

45 kg and greater:

Initial dose: Up to 4.5 g orally per day, divided and given as 2 equal doses of up to 2.25 g/dose

Maintenance dose: The dose may be increased by 1.5 g (OR 0.75 g/dose) orally per night at 1 to 2-week intervals up to 9 g/day.

Maximum dose: 9 g/day

Comments:

• Patients who sleep more than 8 hours/night may be given the first dose at bedtime or after an initial period of sleep.
• Patients weighing less than 20 kg may be given lower initial, maximum, maintenance, and total maximum nightly doses.
• Unequal doses may be required in some patients to attain an optimal response to treatment.
• Both doses should be diluted at the same time at night.
• The first dose should be taken at bedtime, and the other dose should be taken between 2.5 to 4 hours after; some may need to set an alarm to awaken to take the second dose.
• Patients should remain in bed after taking each dose.
• If the second dose is missed, patients should skip the dose and should not take this drug until the next night.
• Dosing may be gradually titrated, and doses should be determined by efficacy and tolerability.

Use: Treatment of cataplexy (excessive daytime sleepiness) in patients with narcolepsy.

Do not drink alcohol or take other sleep medicines together with Xywav. Dangerous side effects or death could occur.

Do not give Xywav to anyone with a rare metabolic disorder called succinic semialdehyde dehydrogenase deficiency (which can cause mental or physical impairment).

To make sure you can safely take Xywav, tell your doctor if you have ever had:

• breathing problems;

• snoring, or sleep apnea (breathing stops during sleep);

• depression or suicidal thoughts;

• psychosis or unusual behaviors (anxiety, agitation, paranoia, aggression, hallucinations);

• liver disease; or

• a drug addiction.

Not approved for use by anyone younger than 7 years old with narcolepsy. Not approved for use by anyone younger than 18 years old with idiopathic hypersomnia.

Pregnancy

Tell your doctor if you are pregnant or plan to become pregnant. It is not known if Xywav can harm your unborn baby.

Breastfeeding 

Tell your healthcare professional if are breastfeeding or plan to breastfeed. Xywav passes into breast milk. You and your doctor should decide if you or your child will take Xywav or breastfeed.

Skip the missed dose and use your next dose at the regular time. Do not use two doses at one time.

Take Xywav only during your normal sleeping hours (wait at least 2 hours after eating).

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of Xywav can be fatal.

Overdose symptoms may include sweating, vomiting, severe confusion, loss of balance or coordination, or seizure (convulsions).

Do not drink alcohol. Dangerous side effects or death could occur.

Do not take other sleep medicines together with Xywav.

Xywav will cause drowsiness and can impair your thinking or reactions. You may still feel sleepy the morning after taking this medicine. Wait at least 6 hours or until you are fully awake before you drive, operate machinery, pilot an airplane, or do anything that requires you to be awake and alert.

Get emergency medical help if you have signs of an allergic reaction to Xywav: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

• weak or shallow breathing, breathing that stops for short periods of time;

• severe drowsiness, feeling light-headed;

• sleepwalking (may result in an injury), waking and confused behavior at night;

• a seizure;

• depression, anxiety, unusual or unpleasant thoughts;

• feelings of low self-worth, loss of interest in things you once enjoyed;

• confusion, paranoia, hallucinations (seeing or hearing things);

• increased tiredness, trouble concentrating; or

• suicidal thoughts or actions.

Common Xywav side effects may include:

• sleepwalking, talking or eating in your sleep;

• new sleep problems, strange dreams, night terrors;

• drowsiness, dizziness, tiredness, headache;

• tremors, anxiety;

• dry mouth, nausea, vomiting, diarrhea;

• weight loss; or

• bedwetting (in children).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Fatal side effects can occur if you take Xywav with other drugs that cause drowsiness or slow your breathing. Ask your doctor before taking cold or allergy medicine, opioid medication, sedatives, muscle relaxers, seizure medicine, or medicine for depression, anxiety, or mental illness.

If you start or stop taking divalproex (Depakote), your doctor may need to adjust your Xywav dose.

Other drugs may interact with calcium, magnesium, potassium, and sodium oxybates, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.