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Learning how to prepare XYWAV for twice- or once-nightly dosing

With XYWAV for idiopathic hypersomnia (IH), dosing can be individualized for you

When you receive your first shipment of XYWAV, be sure to read the Instructions for Use (IFU). You’ll also receive the XYWAV and XYREM REMS Patient Quick Start Guide along with your medication and detailed preparation and dosing instructions. Here’s what you’ll need to know:

  • XYWAV is a liquid taken at bedtime. It is most often taken twice nightly (at bedtime and again 2 ½ to 4 hours later). It can also be taken once nightly (just at bedtime)
  • Your doctor will help you decide which dosing regimen is best for you

Before bedtime

  • Prepare your dose and put it in a safe and secure place. If you are taking 2 doses, prepare both at the same time
  • Before you take XYWAV, each dose should be mixed with approximately ¼ cup of water in the empty pharmacy containers provided to you


  • Take your first dose while in bed and lie down immediately
    • XYWAV can cause sleep very quickly without making you feel drowsy
    • Some people fall asleep within 5 minutes, and most fall asleep within 15 minutes (though the time it takes any individual to fall asleep may vary from night to night)

Taking XYWAV twice nightly? At bedtime and 2 1/2 to 4 hours later

  • If prescribed 2 nightly doses, you must wake up to take the second dose 2 ½ to 4 hours after your first, as instructed by your doctor
    • You may want to set an alarm clock to make sure you wake up to take the second dose
  • If you are prescribed XYWAV twice-nightly and miss the second dose, skip it
    • Never take the 2 doses of XYWAV at one time
  • You should remain in bed after taking each dose of XYWAV

It’s important to remember…

  • Wait at least 2 hours after eating before taking XYWAV
  • Prepared doses should be taken within 24 hours after mixing
  • Store XYWAV in safe place, away from from children and pets

It’s good to know…

During the period of the trial that measured how well XYWAV worked, almost 8 out of 10 people (77%) were following a twice-nighly dosing regimen. Your doctor can help adjust your twice-nightly or once-nightly dosing to a regimen that is right for you.

XYWAV Medication Guide

Read the Instructions for Use in the Medication Guide for detailed instructions on preparing and taking XYWAV.

This Medication Guide helps you with preparing and taking XYWAV.

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XYWAV® (calcium, magnesium, potassium, and sodium oxybates) oral solution, 0.5 g/mL total salts (equivalent to 0.413 g/mL of oxybate) is a prescription medicine used to treat:

  • the following symptoms in people 7 years of age or older with narcolepsy:
    • sudden onset of weak or paralyzed muscles (cataplexy)
    • excessive daytime sleepiness (EDS)
  • idiopathic hypersomnia (IH) in adults.

Important Safety Information

WARNING: Taking XYWAV with other central nervous system (CNS) depressants such as medicines used to make you or your child fall asleep, including opioid analgesics, benzodiazepines, sedating antidepressants, antipsychotics, sedating anti-epileptic medicines, general anesthetics, muscle relaxants, alcohol, or street drugs, may cause serious medical problems, including trouble breathing (respiratory depression), low blood pressure (hypotension), changes in alertness (drowsiness), fainting (syncope), and death.

The active ingredient of XYWAV is a form of gamma-hydroxybutyrate (GHB). Abuse or misuse of illegal GHB alone or with other drugs that cause changes in alertness (or consciousness) has caused serious side effects. These effects include seizures, trouble breathing (respiratory depression), changes in alertness (drowsiness), coma, and death. Call your doctor right away if you or your child has any of these serious side effects.

Because of these risks, you have to go through the XYWAV and XYREM REMS to have your or your child's prescription for XYWAV filled.

Do not take XYWAV if you take or your child takes other sleep medicines or sedatives (medicines that cause sleepiness), drinks alcohol, or has a rare problem called succinic semialdehyde dehydrogenase deficiency.

Keep XYWAV in a safe place to prevent abuse and misuse. Selling or giving away XYWAV may harm others, and is against the law. Tell your doctor if you have ever abused or been dependent on alcohol, prescription medicines, or street drugs.

Anyone who takes XYWAV should not do anything that requires them 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 can cause serious side effects, including the following:

  • Breathing problems, including slower breathing, trouble breathing, and/or short periods of not breathing while sleeping (sleep apnea). People who already have breathing or lung problems have a higher chance of having breathing problems when they use XYWAV.
  • Mental health problems, including confusion, seeing or hearing things that are not real (hallucinations), unusual or disturbing thoughts (abnormal thinking), feeling anxious or upset, depression, thoughts of killing yourself or trying to kill yourself, increased tiredness, feelings of guilt or worthlessness, or difficulty concentrating. Tell your doctor if you or your child have or had depression or have tried to harm yourself or themselves. Call your doctor right away if you have or your child has symptoms of mental health problems or a change in weight or appetite.
  • Sleepwalking. XYWAV can cause sleepwalking, which can cause injuries. Call your doctor if this occurs.

The most common side effects of XYWAV in adults include nausea, headache, dizziness, anxiety, insomnia, decreased appetite, excessive sweating (hyperhidrosis), vomiting, diarrhea, dry mouth, parasomnia (a sleep disorder that can include abnormal dreams, abnormal rapid eye movement (REM) sleep, sleep paralysis, sleep talking, sleep terror, sleep-related eating disorder, sleepwalking, and other abnormal sleep-related events), somnolence, fatigue, and tremor.

The most common side effects of XYREM (which also contains oxybate like XYWAV) in children include nausea, bedwetting, vomiting, headache, weight decrease, decreased appetite, dizziness, and sleepwalking.

XYWAV can cause physical dependence and craving for the medicine when it is not taken as directed. These are not all the possible side effects of XYWAV.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit, or call 1-800-FDA-1088.

Please see full Prescribing Information, including BOXED Warning, and Medication Guide.

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