Xywav® (calcium, magnesium, potassium, and sodium oxybate) Approved for Idiopathic Hypersomnia in Adults

On August 12, 2021, the U.S. Food and Drug Administration (FDA) approved Xywav® (calcium, magnesium, potassium, and sodium oxybate) oral solution to treat adults with idiopathic hypersomnia (IH).1

There are currently an estimated 37,000 people in the United States living with idiopathic hypersomnia, a rare sleep disorder that causes chronic excessive daytime sleepiness. This now makes the first and only FDA-approved drug to treat IH.1,2

Xywav was approved by the FDA in 2020 to treat narcolepsy.1-3

What are the ingredients in Xywav?

The active ingredient in Xywav is a form of gamma-hydroxybutyrate (GHB). GHB is a depressant that acts on the central nervous system.3

How does Xywav work?

Xywav is a central nervous system (CNS) depressant, which can make people severely drowsy. While it is unclear exactly how Xywav works in the body, it is thought that the effects of the drug stimulate a chemical in the brain called GABA, which has a calming effect on the body.1

Evidence for Xywav

Xywav was evaluated in a clinical study that involved 154 adults ranging from 19 to 75 years old who all had idiopathic hypersomnia. Researchers found that those participants who were switched from Xywav to a placebo (inactive pill) had symptoms that worsened when compared to participants who continued taking the drug.2

What are the possible side effects?

The most common side effects of Xywav include:2,3

  • Nausea
  • Headache
  • Dizziness
  • Anxiety
  • Vomiting

Other, more rare side effects may include:2,3

  • Insomnia
  • Decreased appetite
  • Excessive sweating
  • Diarrhea
  • Dry mouth
  • Parasomnia (abnormal sleep occurrences like sleep talking, abnormal dreams, and abnormal REM sleep)
  • Somnolence (a strong desire for sleep or sleeping for long periods of time)
  • Fatigue
  • Tremors

Xywav has a boxed warning, the strictest warning from the FDA. It has this warning for central nervous system (CNS) depression and abuse and misuse.1-3

These are not all the possible side effects of Xywav. Talk to your doctor about what to expect when taking Xywav. You also should call your doctor if you have any changes that concern you when taking Xywav.

Things to know about Xywav

Because of the potential risks of CNS depression and abuse and misuse, Xywav is only available through a restricted program called a Risk Evaluation and Mitigation Strategy (REMS).1-3

Under this REMS program, strict safety measures are put in place. Prescribers and people taking the drug are required to enroll in this program. For example, Xywav can only be prescribed by a certified prescriber, and it can only be dispensed by a certified pharmacy to an enrolled person. It is not available in retail pharmacies.2,3

Serious side effects and medical problems can occur if Xywav is taken with any other CNS depressants like:1

  • Opioid analgesics
  • Benzodiazepines
  • Sedating antidepressants
  • Antipsychotics
  • Sedating anti-epileptic medicines
  • General anesthetics
  • Muscle relaxants
  • Alcohol
  • Street drugs

These medical problems can include:1

  • Trouble breathing
  • Low blood pressure
  • Extreme drowsiness
  • Fainting
  • Death

Your doctor may prescribe a once- or twice-nightly regimen of the oral drug. You should be closely monitored to determine if the dose is right for you.1

Do not operate heavy machinery, drive a car, fly an airplane, or do anything dangerous for at least 6 hours after taking the drug. As with any drug, take only as prescribed by your doctor.1

Before beginning treatment for IH, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.

For more information, read the full prescribing information of Xywav.

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