Xyrem (sodium oxybate) is a prescription drug used to treat certain symptoms of narcolepsy. The drug comes as an oral liquid solution. It’s usually taken at night in two doses.

Xyrem is used in adults and certain children to treat symptoms of narcolepsy. These symptoms include:

The active ingredient in Xyrem is sodium oxybate. (An active ingredient is what makes a drug work.)

Xyrem belongs to a group of drugs called central nervous system depressants.

This article describes the dosages of Xyrem, as well as its strength and how to take it. To learn more about Xyrem, see this in-depth article.

This section describes the usual dosages of Xyrem.

What is Xyrem’s form?

Xyrem is available as an oral liquid solution.

What strength does Xyrem come in?

Xyrem comes in one strength of 0.5 grams (g) per milliliter (mL).

What are the usual dosages of Xyrem?

Your doctor will likely start you on a low dosage and adjust it over time to reach the right amount for you. They’ll ultimately prescribe the smallest dosage that provides the desired effect.

The information below describes dosages that are commonly used or recommended. But be sure to take the dosage your doctor prescribes for you. They’ll determine the best dosage to fit your needs.

Dosage for narcolepsy

The typical starting Xyrem dosage for adults with narcolepsy is 4.5 g divided into two doses.

If necessary, your doctor might increase your nightly dosage by 1.5 g per week.

The recommended maintenance dosage of Xyrem to treat symptoms of narcolepsy in adults is 6–9 g per night divided into two doses. The maximum dosage of Xyrem is 9 g total per night.

Doctors prescribe Xyrem in two divided doses. The first dose is taken at bedtime and the second dose is taken 2.5–4 hours later. Your doctor may split your total nightly dose equally. But some people may benefit from taking unequal doses of Xyrem.

What’s the dosage of Xyrem for children?

Xyrem is used to help treat symptoms of narcolepsy in children ages 7 years and older. The dose of Xyrem in children depends on their body weight in kilograms (kg).*

Doctors prescribe Xyrem in two divided doses. The first dose is taken at bedtime and the second dose is taken 2.5–4 hours later.

Each dose in the following summary table is taken at bedtime and then again 2.5–4 hours later. Some children may require unequal doses of Xyrem.

Body weight rangeStarting doseMaximum dose
20 kg to less than 30 kg1 g or less3 g
30 kg to less than 45 kg1.5 g or less3.75 g
45 kg or more2.25 g or less4.5 g

Doctors can increase the dose of Xyrem for children every week. They may increase the dose by a total of 0.5 g per dose.

For more information about Xyrem’s dosage for children, talk with your child’s doctor or a pharmacist.

* One kg equals approximately 2.2 pounds (lbs).

Is Xyrem used long term?

Yes, Xyrem is usually used as a long-term treatment. If you and your doctor determine it’s safe and effective for your condition, you’ll likely take it long term.

Dosage adjustments

If you have liver failure, your doctor may have you take a lower dose of Xyrem. You’ll still take the drug in two divided doses at bedtime.

The dosage of Xyrem you’re prescribed may depend on several factors. These include:

  • the type and severity of the condition you’re taking the drug to treat
  • your age
  • other conditions you may have (see the “Dosage adjustments” section just above)
  • any medications you take

Xyrem is available as an oral liquid solution. You’ll prepare both doses of Xyrem before bedtime. Using the provided syringe, measure the prescribed amount of Xyrem and place the solution into one of the empty containers provided by the pharmacy. Then add 1/4 cup or 60 milliliters (mL) of water to the solution. Prepare the second dose the same way.

Take your first dose of Xyrem 2 hours after eating, while in bed, and lie down immediately. Your next dose is 2.5–4 hours later. You may need to set an alarm to wake up for your second dose.

For information on the expiration, storage, and disposal of Xyrem, see the “Expiration” section of this article. Or talk with your doctor or pharmacist.

Accessible drug containers and labels

Some pharmacies provide medication labels that:

  • have large print
  • use braille
  • feature a code you can scan with a smartphone to change the text to audio

Ask your pharmacist if they offer these accessibility features.

Let your pharmacist know whether you have trouble opening medication bottles. They may have tips to help make it easier.

If you miss a dose of Xyrem, skip the missed dose, and take your next dose at its usual time. If you’re not sure whether you should take a missed dose, talk with your doctor or pharmacist.

If you need help remembering to take your dose of Xyrem on time, try using a medication reminder. This can include setting an alarm or downloading a reminder app on your phone.

Xyrem has a risk of misuse. This refers to taking a drug in a way or for a reason other than how it was prescribed. Examples of misuse include taking the drug more often or at higher doses than recommended by your doctor. Another example of misuse is taking Xyrem with another central nervous system depressant.

You should take Xyrem exactly as your doctor has prescribed. Misuse increases the risk of overdose, which can lead to trouble breathing, coma, and even death.

Do not take more Xyrem than your doctor prescribes, as this can lead to harmful effects.

Symptoms of overdose

Symptoms caused by an overdose can include:

What to do in case you take too much Xyrem

Call your doctor right away if you think you’ve taken too much Xyrem. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 (or your local emergency number) or go to the nearest emergency room.

Taking Xyrem can lead to physical dependence. This is when your body gets used to a drug and needs it to function as usual.

If you suddenly stop taking Xyrem, you may experience withdrawal symptoms. (These are side effects that can occur when you stop taking a drug that your body has become dependent on.)

Examples of withdrawal symptoms include:

Before ending your Xyrem treatment, your doctor may lower your dosage slowly over time. This can help reduce your risk of withdrawal symptoms after you stop treatment.

If you have withdrawal symptoms after you’ve stopped taking Xyrem, talk with your doctor. They can recommend ways to ease these symptoms.

Below are answers to some commonly asked questions about Xyrem’s dosage.

Can Xyrem be used for insomnia? If so, what’s the dosage?

No, Xyrem isn’t used for insomnia (trouble sleeping). It’s only used to treat symptoms of narcolepsy, which is a long-term neurological sleep disorder.

Because Xyrem isn’t used for insomnia, the drug manufacturer doesn’t provide recommended dosages for this use.

However, some medications in the group of drugs called central nervous system depressants are approved for treating insomnia. (Xyrem is also a central nervous system depressant.) For example, Ambien (zolpidem) is a drug that’s used to treat insomnia.

To learn more about your treatment options for insomnia, talk with your doctor.

How long does it take for Xyrem to start working?

Xyrem starts to work after your first dose. You may fall asleep quickly without feeling tired within 5 minutes of taking your dose. Most people will fall asleep within 15 minutes. You should notice less daytime sleepiness and sudden muscle weakness when taking Xyrem.

Your doctor will monitor the drug’s effectiveness in treating your condition and adjust your dose accordingly.

If you have other questions about what to expect from your Xyrem treatment, talk with your doctor.

The sections above describe the usual dosages provided by Xyrem’s manufacturer. If your doctor recommends this drug for you, they’ll prescribe the dosage that’s right for you.

Remember, you should not change your dosage of Xyrem without your doctor’s recommendation. Only take Xyrem exactly as prescribed. Talk with your doctor if you have questions or concerns about your current dosage.

Here are some examples of questions you may want to ask them:

  • If I have too many side effects from the starting dose of Xyrem, what’s the lowest dose I can take?
  • How will I know what dosage is good for my condition?
  • Can I start at a higher dosage than the recommended starting dosage?

To learn more about Xyrem, see these articles:

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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.