Xywav (calcium, magnesium, potassium, and sodium oxybates)
An approved treatment for Narcolepsy Type 1.
Drug facts
The same compound appears under different names depending on the context. Here is how to identify Calcium, magnesium, potassium, and sodium oxybates wherever you encounter it, plus the key facts at a glance.
- Generic name
- Calcium, magnesium, potassium, and sodium oxybates
- Brand name
- Xywav
- Development code
- JZP-258
- Drug class
- Central nervous system depressant (oxybate)
- Manufacturer
- Jazz Pharmaceuticals
- How it's taken
- Liquid by mouth, mixed with water, taken at night
A nighttime liquid for cataplexy or excessive daytime sleepiness in people 7 years and older with narcolepsy, and for idiopathic hypersomnia in adults.
- It contains the same active part as Xyrem, oxybate, as a mix of calcium, magnesium, potassium and sodium salts.
- The FDA approved it for narcolepsy on July 21, 2020 and for idiopathic hypersomnia on August 12, 2021. It carries the same boxed warning and restricted distribution program as Xyrem and is a Schedule III controlled substance.
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Where Calcium, magnesium, potassium, and sodium oxybates fits
Xywav is a nighttime oxybate liquid for cataplexy or daytime sleepiness in people with narcolepsy aged 7 and older, and it is also the oxybate approved for idiopathic hypersomnia in adults.
- Narcolepsy type 1 is also treated with daytime wake-promoting drugs such as modafinil, stimulants and Wakix (pitolisant), and since August 2026 Orzeyful, which acts on orexin receptors.
- Xyrem and Lumryz contain the same active part as Xywav; Jazz says Xywav has 92% less sodium than sodium oxybate in the 6g to 9g nightly range, and Lumryz is taken once a night.
- No trial has compared Xywav head to head with Xyrem, Lumryz or the daytime medicines.
- A question to bring to a sleep specialist is whether lower sodium matters for a person's heart, blood pressure or kidney health.
How Calcium, magnesium, potassium, and sodium oxybates works
Narcolepsy type 1 is caused by the loss of brain cells that make orexin (also called hypocretin), a chemical messenger that keeps people awake and stabilizes muscle tone, which leads to daytime sleepiness, cataplexy (sudden muscle weakness set off by strong emotions) and broken nighttime sleep. Xywav contains oxybate, gamma-hydroxybutyrate (GHB), which acts on GABA-B receptors that calm nerve activity.
The label says it is thought to work during sleep through those receptors, but how it improves symptoms is unknown[1]. Instead of only sodium, its oxybate is paired with calcium, magnesium, potassium and sodium, which Jazz says gives 92% less sodium than sodium oxybate in the 6g to 9g nightly range[3].
Side effects and safety
- Slowed breathing and other drugs that slow the brain. The label says not to combine it with alcohol or sedative sleep medicines. Opioids, benzodiazepines, sedating antidepressants or antipsychotics, sedating seizure medicines and muscle relaxants raise the risk of slowed breathing, low blood pressure, deep sedation and death. The label says not to drive or do hazardous work for at least 6 hours after a dose.
- Sleep apnea and breathing during sleep. Pauses in breathing and drops in oxygen during sleep can occur.
- Depression and suicidal thoughts. Depression or depressed mood was reported in the trials. New or worse mood changes should be reported right away.
- Confusion, anxiety and sleepwalking. Anxiety was reported by 5% in the narcolepsy trial and 16% over the whole idiopathic hypersomnia trial, and sleepwalking or other sleep behaviors by 5-6%.
- Dispensed only through the XYWAV and XYREM REMS, 1-866-997-3688
- Tell your doctor about every medicine, especially opioids, benzodiazepines and other sedating drugs
- Divalproex (a seizure and mood medicine) raises oxybate levels, so the Xywav dose is lowered by at least 20% when both are used
- Report mood changes, confusion or breathing problems during sleep
Xywav has a boxed warning. It slows the brain and breathing, and slowed breathing and dulled alertness may occur at recommended doses; they occurred at recommended doses in adult trials of sodium oxybate, which has the same active part. Its active part is GHB, and illegal GHB abuse has been linked to seizures, slowed breathing, coma and death, so Xywav is available only through the XYWAV and XYREM REMS program.
The label says it must not be combined with alcohol or sedative sleep medicines, and other drugs that slow the brain, such as opioids and benzodiazepines, raise the risk of dangerous breathing problems. The label also says people should not drive or do hazardous work for at least 6 hours after a dose.
In the narcolepsy trial of 201 adults, the most common side effects were headache (20%), nausea (13%), dizziness (10%), decreased appetite (8%), sleepwalking and other sleep behaviors (6%), diarrhea (6%) and heavy sweating (6%), and 4% stopped because of side effects. In the idiopathic hypersomnia trial of 154 adults, the most common were nausea (21%), headache (16%), anxiety (12%) and dizziness (12%), and 11% stopped. Other warnings cover depression and suicidal thoughts, confusion and anxiety, and sleepwalking[1].
This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.
Taking Calcium, magnesium, potassium, and sodium oxybates
Each dose is mixed with about 1/4 cup (60mL) of water and taken in bed at least 2 hours after eating; people lie down right away. For narcolepsy it is taken in 2 doses each night, the second 2.5 to 4 hours after the first. Adults with narcolepsy start at 4.5g a night and go up by up to 1.5g a night each week to 6g to 9g a night, and the 2 doses can be equal or unequal.
Children 7 and older are dosed by weight, from 20kg up, with the same table as Xyrem. Adults with idiopathic hypersomnia can take it once or twice a night, starting at 3g or less once a night or 4.5g or less in 2 doses, up to 6g once a night or 9g in 2 doses. People switching from Xyrem start at the same dose, gram for gram. People with liver impairment start at half the usual dose, and the dose is lowered by at least 20% when divalproex is started. A missed second dose is skipped[1].
Availability and cost
Only available as the brand-name product.
Help paying for Xywav
With private insurance, the drugmaker's copay card can lower what you pay for Xywav. Drugmaker copay cards can't be used with Medicare, Medicaid or TRICARE, but charity funds often can. Of the 4 charity funds for Narcolepsy Type 1, 3 were open on October 26, 2026. Without insurance, you can apply to the drugmaker's free medicine program, which sets its own eligibility rules. Pick your insurance below to see which offers fit you.
- Copay help
Eligible patients can pay as little as $0 for a 30-day fill of Xywav, subject to monthly and/or annual maximum benefits. Not valid for Medicare, Medicaid, VA or other federal or state healthcare programs.
For: private insurance · source - Free medicine program
Quick Start Voucher for a free 1-month supply, up to 3 bottles, once per lifetime, for eligible new patients.
For: private insurance · source - Bridge or quick-start supply
Bridge Program with up to 4 months of Xywav free for eligible patients during a coverage delay or interruption.
For: private insurance · source - Free medicine program
The JazzCares Patient Assistance Program provides Jazz medicines at no cost to people who are uninsured or whose insurance does not cover the drug, subject to financial and residency criteria.
For: no insurance, underinsured · source - Insurance and case manager help
JazzCares offers a nurse, a pharmacist available 24/7 and a peer mentor program. Phone 1-833-533-JAZZ (5299), Monday to Friday, 8 AM to 8 PM ET.
For: private insurance, Medicare, Medicaid, no insurance · source
Good to know: Jazz does not publish the dollar amount of the copay maximums.
Charity funds for Narcolepsy Type 1
- From a charity · NORD RareCareNarcolepsy Medical Assistance fundOpen
Pays for: Medical and medication costs.
The foundation says: “Accepting Applications” - From a charity · NORD RareCareNarcolepsy Premium Copay Assistance fundOpen
Pays for: Insurance premiums and copays.
The foundation says: “Accepting Applications” - From a charity · TotalAssist (formerly PAN Foundation)Narcolepsy fundOpen
Pays for: Out-of-pocket costs for approved medications, up to $5,000 per year. Requires health insurance (any kind).
- From a charity · The Assistance FundNarcolepsy fundWaitlist
Pays for: Copays, coinsurance, deductibles and other health-related expenses.
Access and eligibility
Approved for cataplexy or excessive daytime sleepiness in people 7 years and older with narcolepsy, and for idiopathic hypersomnia in adults. Not for use with alcohol or sedative sleep medicines, or in succinic semialdehyde dehydrogenase deficiency, a rare inherited condition. Prescribers and the dispensing pharmacy must be certified in the XYWAV and XYREM REMS, and patients must be enrolled. Schedule III controlled substance.
Source: JazzCares for Xywav (Jazz Pharmaceuticals)
Access program details are provided for informational purposes and may vary based on insurance coverage, geographic location, and individual circumstances. Confirm current eligibility directly with the manufacturer or your specialty pharmacy.
Clinical trial results
In the narcolepsy trial (NCT03030599, 201 adults), people stabilized on Xywav were then randomly switched to placebo or kept on Xywav for 2 weeks. Weekly cataplexy attacks rose by an average of 11.5 on placebo against 0.1 on Xywav, and Epworth Sleepiness Scale scores, a 0 to 24 questionnaire where lower means less sleepy, rose by 3.0 on placebo against 0.0 on Xywav[1][4].
In the idiopathic hypersomnia trial (NCT03533114, 154 adults), Epworth scores rose by a median of 8.0 on placebo against 0.0 on Xywav[1][5]. Xywav was not studied in a children's trial; its use from age 7 rests on the Xyrem children's trial and drug level data. No trial has compared Xywav head to head with Xyrem or other narcolepsy medicines.
Development history
Jazz developed Xywav under the code JZP-258. The FDA approved it on July 21, 2020 for cataplexy or excessive daytime sleepiness in people 7 and older with narcolepsy, and on August 12, 2021 for idiopathic hypersomnia in adults, according to Drugs@FDA[2][3]. Drugs@FDA lists no approved generic of Xywav[2].
Explore Narcolepsy Type 1 trials
Other Narcolepsy Type 1 treatments
Narcolepsy type 1 has been treated with wake-promoting drugs such as modafinil and armodafinil, stimulants, oxybate medicines taken at night (Xyrem, Xywav and Lumryz), and pitolisant. Orzeyful, approved August 5, 2026, adds a treatment that acts on orexin receptors.
Common questions about Calcium, magnesium, potassium, and sodium oxybates
▸What is Calcium, magnesium, potassium, and sodium oxybates (Xywav)?
A nighttime liquid for cataplexy or excessive daytime sleepiness in people 7 years and older with narcolepsy, and for idiopathic hypersomnia in adults. It contains the same active part as Xyrem, oxybate, as a mix of calcium, magnesium, potassium and sodium salts. The FDA approved it for narcolepsy on July 21, 2020 and for idiopathic hypersomnia on August 12, 2021. It carries the same boxed warning and restricted distribution program as Xyrem and is a Schedule III controlled substance.
▸How does Calcium, magnesium, potassium, and sodium oxybates work?
Narcolepsy type 1 is caused by the loss of brain cells that make orexin (also called hypocretin), a chemical messenger that keeps people awake and stabilizes muscle tone, which leads to daytime sleepiness, cataplexy (sudden muscle weakness set off by strong emotions) and broken nighttime sleep. Xywav contains oxybate, gamma-hydroxybutyrate (GHB), which acts on GABA-B receptors that calm nerve activity. The label says it is thought to work during sleep through those receptors, but how it improves symptoms is unknown[1]. Instead of only sodium, its oxybate is paired with calcium, magnesium, potassium and sodium, which Jazz says gives 92% less sodium than sodium oxybate in the 6g to 9g nightly range[3].
▸What are the side effects of Calcium, magnesium, potassium, and sodium oxybates?
Xywav has a boxed warning. It slows the brain and breathing, and slowed breathing and dulled alertness may occur at recommended doses; they occurred at recommended doses in adult trials of sodium oxybate, which has the same active part. Its active part is GHB, and illegal GHB abuse has been linked to seizures, slowed breathing, coma and death, so Xywav is available only through the XYWAV and XYREM REMS program. The label says it must not be combined with alcohol or sedative sleep medicines, and other drugs that slow the brain, such as opioids and benzodiazepines, raise the risk of dangerous breathing problems. The label also says people should not drive or do hazardous work for at least 6 hours after a dose. In the narcolepsy trial of 201 adults, the most common side effects were headache (20%), nausea (13%), dizziness (10%), decreased appetite (8%), sleepwalking and other sleep behaviors (6%), diarrhea (6%) and heavy sweating (6%), and 4% stopped because of side effects. In the idiopathic hypersomnia trial of 154 adults, the most common were nausea (21%), headache (16%), anxiety (12%) and dizziness (12%), and 11% stopped. Other warnings cover depression and suicidal thoughts, confusion and anxiety, and sleepwalking[1].
▸How is Calcium, magnesium, potassium, and sodium oxybates taken?
Each dose is mixed with about 1/4 cup (60mL) of water and taken in bed at least 2 hours after eating; people lie down right away. For narcolepsy it is taken in 2 doses each night, the second 2.5 to 4 hours after the first. Adults with narcolepsy start at 4.5g a night and go up by up to 1.5g a night each week to 6g to 9g a night, and the 2 doses can be equal or unequal. Children 7 and older are dosed by weight, from 20kg up, with the same table as Xyrem. Adults with idiopathic hypersomnia can take it once or twice a night, starting at 3g or less once a night or 4.5g or less in 2 doses, up to 6g once a night or 9g in 2 doses. People switching from Xyrem start at the same dose, gram for gram. People with liver impairment start at half the usual dose, and the dose is lowered by at least 20% when divalproex is started. A missed second dose is skipped[1].
▸Is Calcium, magnesium, potassium, and sodium oxybates FDA approved?
Yes, Calcium, magnesium, potassium, and sodium oxybates (Xywav) is FDA approved (2020) for the treatment of Narcolepsy Type 1.
▸What is the difference between Xywav and Xyrem?
Both contain oxybate and share the same boxed warning, REMS program and narcolepsy dosing, but Xywav uses a mix of calcium, magnesium, potassium and sodium salts.
Sodium: Jazz says Xywav has 92% less sodium than sodium oxybate in the 6g to 9g nightly range, about 1,000 to 1,500mg less a night.
Other uses: Xywav is also approved for idiopathic hypersomnia in adults.
Trials: no trial compared the 2 head to head.
Source: Xywav and Xyrem labels on DailyMed; Jazz release, July 22, 2020
▸How do you take Xywav?
For narcolepsy, Xywav is taken in 2 doses each night, the first in bed at least 2 hours after eating and the second 2.5 to 4 hours later.
Adult dose: 4.5g a night or less to start, up to 6g to 9g a night.
Idiopathic hypersomnia: adults may take it once a night, up to 6g, or twice a night, up to 9g.
Source: Xywav label on DailyMed, revised July 2025
▸Is there a generic Xywav?
No. Drugs@FDA listed no approved generic of Xywav as of November 10, 2026.
Source: Drugs@FDA
▸What are the side effects of Xywav?
In the adult narcolepsy trial the most common were headache (20%), nausea (13%), dizziness (10%) and decreased appetite (8%).
Idiopathic hypersomnia trial: nausea 21%, headache 16%, anxiety 12%, dizziness 12%.
Serious risks: slowed breathing, especially with alcohol, opioids or other sedating drugs.
Source: Xywav label on DailyMed, revised July 2025
Sources and references
Every factual claim on this page is drawn from the public sources listed below. Click any reference to open the original document.
- U.S. National Library of Medicine · 2025-07. XYWAV- calcium, magnesium, potassium, and sodium oxybates solution. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1e0ae43a-037f-42af-8e23-a0e51d75abe8
- U.S. Food and Drug Administration. Drugs@FDA: XYWAV (NDA 212690) approval history. https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=212690
- Jazz Pharmaceuticals via PR Newswire · 2020-07-22. Jazz Pharmaceuticals Announces U.S. FDA Approval of Xywav (calcium, magnesium, potassium, and sodium oxybates) Oral Solution for Cataplexy or Excessive Daytime Sleepiness Associated with Narcolepsy. https://www.biospace.com/jazz-pharmaceuticals-announces-u-s-fda-approval-of-xywav-calcium-magnesium-potassium-and-sodium-oxybates-oral-solution-for-cataplexy-or-excessive-daytime-sleepiness-associated-with-narcolepsy
- ClinicalTrials.gov. A Study of the Efficacy and Safety of JZP-258 in Subjects With Narcolepsy With Cataplexy. https://clinicaltrials.gov/study/NCT03030599
- ClinicalTrials.gov. A Multicenter Study of the Efficacy and Safety of JZP-258 in the Treatment of Idiopathic Hypersomnia (IH) With an Open-label Safety Extension. https://clinicaltrials.gov/study/NCT03533114
- Jazz Pharmaceuticals. JazzCares | Xywav Patients. https://www.jazzcares.com/patients/xywav