Why Narcolepsy Patients Are Switching from Xyrem® (SXB) to Xywav® (LXB)
Last updated: April 2023
Doctors have long prescribed sodium oxybate (Xyrem®) for narcolepsy. Xyrem, or SXB, helps with cataplexy, excessive daytime sleepiness, and disrupted nighttime sleep. However, SXB has a lot of sodium in it. This can be bad if you have heart disease, diabetes, or obesity. High sodium intake damages your heart and blood vessels and causes high blood pressure.1
In 2020, a drug called oxybate (Xywav®) was approved to treat narcolepsy. Xywav, or LXB, has 92 percent less sodium than SXB and works just as well. People reported little to no trouble switching from SXB to LXB. A lower-sodium alternative to control narcolepsy symptoms is better for your health.2
How do SXB and LXB compare?
SXB was approved to treat cataplexy in 2002 and excessive daytime sleepiness in 2005. LXB was approved to treat both conditions in 2020. The active ingredient in SXB is sodium oxybate, also known as gamma hydroxybutyrate or GHB. LXB also contains GHB along with its other active ingredients:1,3,4
- Calcium oxybate
- Magnesium oxybate
- Potassium oxybate
The main difference in the 2 drugs is that LXB does not have as much sodium as SXB. Depending on your adult dose, SXB can have 1100 to 1640 milligrams (mg) of sodium. Instead of sodium, LXB has calcium, magnesium, and potassium.1
Why is a drug with less sodium important?
The American Heart Association and American College of Cardiology say that adults should have less than 1500 mg of sodium per day. Most adults in the United States get 3400 mg of sodium a day. If you have a high-sodium diet and take SXB, you are likely getting too much sodium. Too much sodium in your diet is linked to:1
- High blood pressure
- Heart problems
- Kidney problems
High sodium worsens health problems. It can worsen obesity and diabetes. Since people with narcolepsy already have higher rates of obesity, diabetes, heart disease, and high blood pressure, the increased risk that sodium has on your health is concerning.1
How does sodium harm my body?
If you have too much sodium, your body retains water. More water means more work for your heart and blood vessels. This strains the body. It raises your blood pressure, which can damage your kidneys and other organs.5,6
Does LXB work as well as SXB?
An ongoing study of 79 people with narcolepsy switching from SXB to LXB showed that after one week on LXB, people had:7
- Less excessive sweating (40.5 percent on SXB to 26.6 percent on LXB)
- Less dizziness (27.4 percent on SXB to 13.9 percent on LXB)
- Slightly lower Epworth Sleepiness Scale scores (from 9.9 to 9.7)
Those in the study also had similar scores on the Functional Outcomes of Sleep Questionnaire (Short Version) and the British Columbia Cognitive Complaints Inventory.
Most people in this study switched to LXB to improve their health. Many people also wanted to lessen their current heart problems.7
Similar results were found in a smaller study with 21 people with narcolepsy. After 6 weeks, 57 percent of those who switched to LXB noticed symptom improvement. As for switching, 90.5 percent said it was not hard. Plus, some say they have better quality of life on LXB.2,7
What are the side effects of LXB?
Side effects of LXB include:4
- Nausea, vomiting, diarrhea
- Sleep disturbances (parasomnia, sleep paralysis, sleepwalking, sleep talking, sleep terror, sleep-related eating disorder)
- Anxiety, changes in thinking or mental health
- Excessive sweating
- Changes in breathing
It is dangerous to take LXB if you need to focus or operate machinery within 6 hours. Talk with your doctor about any possible side effects that you are concerned about or are having.4
LXB is newer but has been shown to control cataplexy just like SXB. Because it has less sodium, the US Food and Drug Administration says that LXB is “clinically superior” to SXB. Talk to your doctor if you think this lower-sodium option may help you.
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