Calcium Oxybate, Magnesium Oxybate, Potassium Oxybate, and Sodium Oxybate

Pronunciation: KAL-see-um oX-i-bate, mag-NEE-zee-um oX-i-bate, poe-TAS-ee-um oX-i-bate, and SOE-dee-um OX-i-bate
Generic name: calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate
Brand name: Xywav
Dosage form: oral solution(0.5 g per mL)
Drug class: Miscellaneous anxiolytics, sedatives and hypnotics

Medically reviewed by Carmen Pope, BPharm. Last updated on May 24, 2024.

What are calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate?

Calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate (Xywav) are used to treat cataplexy (weak or paralyzed muscles) or to reduce excessive daytime sleepiness caused by narcolepsy.

Calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate are 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.

This combination of oxybates is a central nervous system depressant and is available as an oral solution. Xywav is a low-sodium alternative to Xyrem.

One of the ingredients in Xywav is sodium oxybate which is also known as GHB, a known street drug of abuse. Because of the potential for abuse and serious side effects, this formulation is only available from a certified pharmacy under a special program (XYWAV REMS). You must be registered in the program and understand the risks and benefits of this medicine.

The combination of calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate was FDA-approved on July 21, 2020, under the brand Xywav. There is no Xywav generic.

Is calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate a controlled substance?

Yes, the combination of calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate 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. An active ingredient contained in the formulation is a form of gamma-hydroxybutyrate (GHB). Abuse of illegal GHB, either alone or with other CNS depressants, may cause serious medical problems.

Calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate side effects

Get emergency medical help if you have signs of an allergic reaction to the oxybates, such as hives; difficulty breathing, or 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;

• 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 oxybate side effects affecting 5% or more adults who take it for narcolepsy or IH include:

• nausea, headache, dizziness, anxiety, insomnia, decreased appetite, increased sweating, vomiting, diarrhea, dry mouth, parasomnias (unnatural movements, behaviors, emotions, perceptions, and dreams that occur while falling asleep, during sleep, between sleep stages or upon waking, such as sleepwalking, or talking or eating in your sleep, strange dreams, night terrors;

• drowsiness, dizziness, tiredness, or fatigue

• tremors

• anxiety

• dry mouth, nausea, vomiting, or diarrhea.

In children, the most common side effects of calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate affecting 5% or more children include nausea, bed wetting, headache, weight loss, decreased appetite, dizziness, and sleepwalking.

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 the FDA at 1-800-FDA-1088.

Warnings

Calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate 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 the formulation or you know how the formulation affects you or your child.

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

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

Calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate (Xywav) may be habit-forming. Misuse can cause addiction, overdose, or death. Keep the medication in a place where others cannot get to it.

Taking oxybates may increase your risk for depression and suicidal thoughts, or decrease your mood further if you already have depression. It may also cause confusion and anxiety. 5% to 6% of people taking calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate experience parasomnias, including sleepwalking, that may be associated with injury. Tell your healthcare provider immediately if you suspect parasomnias in yourself or your child.

Before taking this medicine

Do not drink alcohol or take other sleep medicines together with calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate (Xywav). Dangerous side effects or death could occur.

Do not give oxybates 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 calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate, tell your healthcare provider 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.

Also tell your healthcare provider if you are pregnant, planning to become pregnant, or breastfeeding.

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 calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate (Xywav) can harm your unborn baby.

Breastfeeding

Tell your healthcare professional if are breastfeeding or plan to breastfeed. Oxybates pass into breast milk. Talk to your healthcare provider about the best way to feed your baby.

How should I take calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate?

Take calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate (Xywav) exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. The formulation can cause severe drowsiness, slow or stop your breathing, and be habit-forming or addictive, even at regular doses or if you are also taking stimulant medicine.

• 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.

Wait at least 2 hours after eating before taking or giving a dose of oxybates.

• It is usually taken as 1 nightly dose or as 2 doses (once at bedtime and again 2.5 to 4 hours later).
• Calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate (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 calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate (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 oxybates 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 misuse it.
• Throw away any dose not used within 24 hours after mixing.
• Do not keep leftover oxybate liquid. Ask your pharmacist where to locate a drug take-back disposal program. If there is no take-back program, pour unused liquid medicine down a sink drain.

Calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate (Xywav) dosing information

Narcolepsy (Adult)

Initial dose: 4.5 g orally per day. Divide and give as 2 equal doses of 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.

Idiopathic Hypersomnia (Adult)

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.

Narcolepsy (Children 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.

Related/similar drugs

Xyrem, Adderall, methylphenidate, Ritalin, Concerta, modafinil, dextroamphetamine, Xywav, sodium oxybate, Lumryz

What happens if I miss a dose?

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

Take calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate only during your normal sleeping hours (wait at least 2 hours after eating).

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate (Xywav) can be fatal.

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

What should I avoid while taking this medicine?

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

Do not take other sleep medicines together with calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate.

Oxybates will cause drowsiness and can impair your thinking or reactions. You may still feel sleepy in 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.

What other drugs will affect this medicine?

Fatal side effects can occur if you take calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate 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 dose.

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

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

Xywav ingredients

Active ingredients: calcium oxybate, magnesium oxybate, potassium oxybate, and sodium oxybate (gamma-hydroxybutyrate (GHB).

Inactive ingredients: purified water and sucralose.

Storage

Store between 20° C to 25° C (68° F to 77° F).

Dispense in tight containers.

Solutions prepared following dilution should be consumed within 24 hours.

Keep out of reach of children.

Manufacturer

Jazz Pharmaceuticals, Inc.

Popular FAQ

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer