Proper Use

Drug information provided by: Merative, Micromedex®

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. If too much is taken, it may become habit-forming. If you think this medicine is not working properly after you have taken it for several weeks, check with your doctor first and do not increase the dose.

It is very important that you understand the requirements of the Xywav® and Xyrem® REMS program, and become familiar with the Xywav® Medication Guide and patient instructions. Ask your doctor if you have any questions.

This medicine can be taken as a single dose (for idiopathic hypersomnia) or divided into 2 nightly doses. The first nightly dose should be taken at least 2 hours after you eat.

This medicine can make you sleep very quickly (within 5 to 15 minutes) without feeling drowsy. It is best to take the medicine only at bedtime or when you are ready to fall asleep. Take it only at bedtime and while in bed.

Measure your dose with the marked plastic syringe that comes with the medicine. Mix it with 1/4 cup of water. Mix both doses before you go to bed. Store the second dose close to your bed in a child, out of the reach of children.

Take the second dose 2 1/2 to 4 hours after you take the first dose. You may need to set an alarm clock to wake you up so you can take the second dose on time. Remain on your bed after taking the first and second doses of this medicine.

Use the medicine within 24 hours after it has been mixed with water.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (solution):
    • For cataplexy or excessive daytime sleepiness:
      • Adults—At first, 2.25 grams (g) taken at bedtime (first dose), then 2.25 g taken 2.5 to 4 hours later (second dose). Your doctor may adjust your dose as needed and tolerated. However, the dose is usually not more than 9 g per night.
      • Children 7 years of age and older—Dose is based on body weight and must be determined by your doctor:
        • Weighing 45 kilograms (kg) or more—At first, 2.25 g or less given at bedtime and repeated one time during the night. The first dose should be taken at bedtime and the second dose taken 2.5 to 4 hours later. Your doctor may adjust your dose as needed and tolerated. However, the dose is usually not more than 4.5 g per night.
        • Weighing 30 kg to less than 45 kg—At first, 1.5 g or less given at bedtime and repeated one time during the night. The first dose should be taken at bedtime and the second dose taken 2.5 to 4 hours later. Your doctor may adjust your dose as needed. However, the dose is usually not more than 3.75 g per night.
        • Weighing 20 to less than 30 kg—At first, 1.0 g or less given at bedtime and repeated one time during the night. The first dose should be taken at bedtime and the second dose taken 2.5 to 4 hours later. Your doctor may adjust your dose as needed. However, the dose is usually not more than 3 g per night.
      • Children younger than 7 years of age or weighing less than 20 kg—Use and dose must be determined by your doctor.
    • For idiopathic hypersomnia:
      • Once a night dosing:
        • Adults—At first, 3 grams (g) or less taken at bedtime. Your doctor may adjust your dose as needed and tolerated. However, the dose is usually not more than 6 g per night.
        • Children—Use and dose must be determined by your doctor.
      • Two times a night dosing:
        • Adults—At first, 4.5 grams (g) or less taken at bedtime, divided into two doses (eg, 2.25 g each). Your doctor may adjust your dose as needed and tolerated. However, the dose is usually not more 9 g per night.
        • Children—Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of this medicine, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

If you miss the second dose, skip that dose and do not take any more medicine until the next night. Do not use extra medicine to make up for a missed dose.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Pour any unused medicine down the sink drain after 24 hours. Use a marker to cross out the label on the bottle, then throw it in the trash.

Portions of this document last updated: April 01, 2024

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