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Last reviewed on RxList: 2/14/2017
Xyrem Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 02/15/2017

Xyrem (sodium oxybate) is a central nervous system depressant drug indicated for the treatment of excessive daytime sleepiness and cataplexy in patients with narcolepsy. Side effects of Xyrem include:

  • dizziness,
  • nausea,
  • vomiting,
  • diarrhea, or
  • shallow breathing.

Tell your doctor if you have serious side effects of Xyrem including:

The recommended starting dose of Xyrem is 4.5 grams per night administered orally in two equal, divided doses: 2.25 g at bedtime and 2.25 g taken 2.5 to 4 hours later. Xyrem may interact with alcohol or other drugs used for sleep or sedation, including cold medicines, narcotics, muscle relaxers, or medicines for anxiety, depression, or seizures. Tell your doctor all medications and supplements you use. Tell your doctor if you are pregnant or plan to become pregnant during treatment with Xyrem. Xyrem is not expected to harm a fetus. It is unknown if Xyrem passes into breast milk. Consult your doctor before breastfeeding.

Our Xyrem (sodium oxybate) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Xyrem Consumer Information

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using sodium oxybate and call your doctor at once if you have:

  • hallucinations (seeing or hearing things), severe confusion;
  • depression, agitation, unusual or unpleasant thoughts;
  • suicidal thoughts or actions;
  • shallow breathing;
  • bed-wetting;
  • sleepwalking; or
  • waking and confused behavior at night.

Common side effects may include:

  • dizziness;
  • nausea, vomiting; or
  • diarrhea.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Xyrem (Sodium Oxybate)

Xyrem Professional Information


The following adverse reactions appear in other sections of the labeling:

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

Xyrem was studied in three placebo-controlled clinical trials (Trials N1, N3, and N4, described in Sections 14.1 and 14.2) in 611 patients with narcolepsy (398 subjects treated with Xyrem, and 213 with placebo). A total of 781 patients with narcolepsy were treated with Xyrem in controlled and uncontrolled clinical trials.

Section 6.1 and Table 3 presents adverse reactions from three pooled, controlled trials (N1, N3, N4,) in patients with narcolepsy.

Adverse Reactions Leading to Treatment Discontinuation:

Of the 398 Xyrem-treated patients with narcolepsy, 10.3% of patients discontinued because of adverse reactions compared with 2.8% of patients receiving placebo. The most common adverse reaction leading to discontinuation was nausea (2.8%). The majority of adverse reactions leading to discontinuation began during the first few weeks of treatment.

Commonly Observed Adverse Reactions in Controlled Clinical Trials:

The most common adverse reactions (incidence ≥ 5% and twice the rate seen with placebo) in Xyrem-treated patients were nausea, dizziness, vomiting, somnolence, enuresis, and tremor.

Adverse Reactions Occurring at an Incidence of 2% or greater:

Table 3 lists adverse reactions that occurred at a frequency of 2% or more in any treatment group for three controlled trials and were more frequent in any Xyrem treatment group than with placebo. Adverse reactions are summarized by dose at onset. Nearly all patients in these studies initiated treatment at 4.5 g per night. In patients who remained on treatment, adverse reactions tended to occur early and to diminish over time.

Table 3 :Adverse Reactions Occurring in ≥ 2% of Patients and More Frequently with Xyrem than Placebo in Three Controlled Trials (N1, N3, N4) by Body System and Dose at Onset

System Organ Class /MedDRA Preferred Term  Placebo
(n=213) % 
Xyrem 4.5g
(n=185) % 
Xyrem 6g
(n=258) % 
Xyrem 9g
(n=178) % 
Nausea  3 8 13 20
Vomiting  1 2 4 11
Diarrhea  2 4 3 4
Abdominal pain upper  2 3 1 2
Dry mouth  2 1 2 1
Pain  1 1 < 1  3
Feeling drunk  1 0 < 1  3
Edema peripheral  1 3 0 0
Pain in extremity  1 3 1 1
Cataplexy  1 1 1 2
Muscle spasms  2 2 < 1  2
Dizziness  4 9 11 15
Somnolence  4 1 3 8
Tremor  0 0 2 5
Paresthesia  1 2 1 3
Disturbance in attention  0 1 0 4
Sleep paralysis  1 0 1 3
Disorientation  1 1 2 3
Anxiety  1 1 1 2
Irritability  1 0 < 1  3
Sleep walking  0 0 0 3
Enuresis  1 3 3 7
Hyperhidrosis  0 1 1 3

Dose-Response Information

In clinical trials in narcolepsy, a dose-response relationship was observed for nausea, vomiting, paresthesia, disorientation, irritability, disturbance in attention, feeling drunk, sleepwalking, and enuresis. The incidence of all these reactions was notably higher at 9 g per night.

In controlled trials in narcolepsy, discontinuations of treatment due to adverse reactions were greater at higher doses of Xyrem.

Postmarketing Experience

The following additional adverse reactions that have a likely causal relationship to Xyrem exposure have been identified during postmarketing use of Xyrem. These adverse reactions include: arthralgia, decreased appetite, fall, fluid retention, hangover, headache, hypersensitivity, hypertension, memory impairment, panic attack, vision blurred, and weight decreased. Because these reactions are reported voluntarily, it is not always possible to reliably estimate their frequency.

Read the entire FDA prescribing information for Xyrem (Sodium Oxybate)

Related Resources for Xyrem

Read the Xyrem User Reviews »

© Xyrem Patient Information is supplied by Cerner Multum, Inc. and Xyrem Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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