Sodium oxybate

Definition

Sodium oxybate is primarily used to treat cataplexy attacks (episodes of weak or paralyzed muscles) in patients with narcolepsy , a condition that causes excessive sleepiness.

Purpose

There is no known cure for narcolepsy. Sodium oxybate is specifically indicated only for the treatment of cataplexy; it does not promote wakefulness or relieve excessive sleepiness, the main symptom of narcolepsy.

Description

Sodium oxybate is also sold in the United States under the name Xyrem. It is a Schedule III, federally controlled substance. Sodium oxybate has a high potential for abuse and is commonly known by its non-medical name, GHB. Patients who are prescribed sodium oxybate should use care when storing and disposing of the medication and its containers.

Recommended dosage

Sodium oxybate is taken as an oral solution, mixed with water. Physicians prescribe it in varying dosages. Sodium oxybate is usually taken in two divided doses, the first administered at bedtime and the second 2.5–4 hours later. As the medication induces sleep quickly, an alarm clock is sometimes needed to wake the person for the second dose. Typical adult daily dosages range from .17–.31 oz (5–9 g). If the first half of a daily divided dose is missed, it should be taken as soon as possible. If the second half of a daily divided dose is missed, that dose should be skipped and no more sodium oxybate should be taken until the following day. Two doses of sodium oxybate should never be taken at the same time.

Sodium oxybate works quickly, relaxing muscles and inducing sleep. As food will decrease the amount of sodium oxybate absorbed into the body, patients should not take the medication with meals.

Precautions

Sodium oxybate may be habit forming and has a high potential for non-medical abuse. When taking the medication, it is important to follow physician instructions precisely.

Sodium oxybate is sleep inducing and takes effect quickly. It should, therefore, be taken only at bedtime and while in bed. It may also cause clumsiness and impair clarity of thinking. It can exacerbate the side effects of alcohol and other medications. A physician should be consulted before taking sodium oxybate with certain non-prescription medications. Patients should avoid alcohol and central nervous system (CNS) depressants (medications that can make one drowsy or less alert, such as antihistimines, sleep medications, and some pain medications) while taking sodium oxybate because they can exacerbate the side effects.

Sodium oxybate may not be suitable for persons with a history of hypopnea (abnormally slow breathing), sleep apnea , liver or kidney disease, depression , metabolic disorders, high blood pressure, angina (chest pain), or irregular heartbeats and other heart problems.

Before beginning treatment with sodium oxybate, patients should notify their physician if they have a history of consuming a large amount of alcohol or a history of drug use. In these cases, dependence on sodium oxybate may be more likely to develop.

Patients who become pregnant while taking sodium oxybate should contact their physician immediately. Taking sodium oxybate while pregnant may cause fetal harm.

Side effects

Research indicates that sodium oxybate, when used under a physician's direction, is generally well tolerated. However, sodium oxybate may case a variety of usually mild side effects. These side effects usually do not require medical attention, and may diminish with continued use of the medication. They include:

• flu-like feeling
• abdominal pain
• difficulty sleeping
• nightmares
• nervousness or anxiety
• depression
• diarrhea
• dry mouth
• runny nose
• neck pain or stiffness
• back pain
• nausea or vomiting
• headache

Other, uncommon side effects of sodium oxybate can be potentially serious. A patient taking soduim oxybate who experiences any of the following symptoms should immediately contact their physician:

• sleepwalking
• change in vision
• ringing or pounding in the ears
• problems with memory
• numbness or tingling feelings on the skin
• disorientation, fainting , or loss of consciousness
• irregular heartbeat
• shortness of breath
• hives, rashes, or bluish patches on the lips and skin
• chest pain
• severe headache

Interactions

Sodium oxybate may have negative interactions with some anticoagulants (blood thinners), antidepressants, antifungals, antibiotics, asthma medications, barbiturates, and monoamine oxidase inhibitors (MAOIs). Seizure prevention medications diazepam (Valium), phenobarbital (Luminal, Solfoton), phenytoin (Dilantin), propranolol (Inderal), and rifampin (Rifadin, Rimactane) may also adversely react with sodium oxybate.

Resources

BOOKS

Parker, James N., and Philip N. Parker. The Official Patient's Sourcebook on Narcolepsy. San Diego: ICON Health, 2002.

OTHER

"Sodium Oxybate (Systemic)." Medline Plus. National Library of Medicine. May 13, 2004 (May 27, 2004). <http://www.nlm.nih.gov/medlineplus/druginfo/uspdi/500407.html>.

"Xyrem (Sodium Oxybate) Oral Solution Medication Guide." U.S. Food and Drug Administration Center for Drug Evaluation and Research. May 13, 2004 (May 27, 2004). <http://www.fda.gov/cder/drug/infopage/xyrem/medicationguide.htm>.

ORGANIZATIONS

Center for Narcolepsy. 701B Welch Road; Room 146, Palo Alto, CA 94304-5742. (650) 725-6517; Fax: (650) 725-4913. <http://www-med.stanford.edu/school/Psychiatry/narcolepsy/>.

Adrienne Wilmoth Lerner