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Xywav

Generic name: calcium, magnesium, potassium, and sodium oxybates (KAL see um, mag NEE zee um, poe TAS ee um, and SOE dee um OX i bate)
Brand name: Xywav
Drug class: Miscellaneous anxiolytics, sedatives and hypnotics

Medically reviewed by Judith Stewart, BPharm. Last updated on Nov 17, 2020.

What is Xywav?

Xywav is an oral solution containing a combination of calcium, magnesium, potassium, and sodium oxybates. It a central nervous system depressant.

Xywav is used to treat cataplexy (sudden loss of muscle strength) or to reduce daytime sleepiness caused by narcolepsy.

Xywav is for use in adults and children at least 7 years old.

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. You must be registered in the program and understand the risks and benefits of this medicine.

Warnings

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.

Xywav is a federal controlled substance (CIII). The active ingredient of Xywav is a form of gammahydroxybutyrate (GHB) that is also a federal controlled substance (CI). Abuse of illegal GHB, either alone or with other CNS depressants, may cause serious medical problems.

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.

Before taking this medicine

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 who has a rare metabolic disorder called succinic semialdehyde dehydrogenase deficiency (which can cause mental or physical impairment).

To make sure Xywav is safe for you, tell your doctor if you have ever had::

Tell your doctor if you are pregnant or breastfeeding.

Xywav is not approved for use by anyone younger than 7 years old.

How should I take this medicine?

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.

Take Xywav at least 2 hours after a meal.

Xywav is usually taken in 2 doses, once at bedtime and again 2.5 to 4 hours later. This medicine works very fast and should be taken while you are sitting in bed ready for sleep. Lie down right away after taking the medicine.

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.

Each dose of Xywav must be mixed with 2 ounces (1/4 cup) of water in the child-resistant dosing cups provided with the medication. Both doses must be used within the same night. Throw away any Xywav dose that has been mixed with water but not used within 24 hours of mixing.

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 safely stop using this medicine.

Store at room temperature away from moisture and heat.

Keep track of your medicine. You should be aware if anyone is using it improperly or without a prescription.

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.

Dosing information

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.

Usual Pediatric Dose of Xywav 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.

What happens if I miss a dose?

If you miss the second dose, skip that dose and take your regular doses the following night. Do not take two doses at one time.

Take Xywav 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 Xywav can be fatal.

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

What to avoid

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

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.

Do not take other sleep medicines together with Xywav.

Side Effects

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:

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.

What other drugs will affect this medicine?

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 Xywav, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

More about Xywav (calcium oxybate / magnesium oxybate / potassium oxybate / sodium oxybate)

Consumer resources

Professional resources

Related treatment guides

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Xywav only for the indication prescribed.

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