GHB, sold as a prescription medication under the brand names Xyrem and Xywav, is approved in the United States to treat two symptoms of narcolepsy: cataplexy (sudden muscle weakness or paralysis) and excessive daytime sleepiness. It is approved for patients 7 years of age and older. In parts of Europe, a separate formulation is also prescribed to help manage alcohol withdrawal and maintain sobriety.
Narcolepsy: The Primary Approved Use
Narcolepsy is a neurological condition where the brain struggles to regulate sleep-wake cycles. People with narcolepsy often experience overwhelming daytime drowsiness no matter how much they sleep at night, and many also have cataplexy, episodes where emotions like laughter or surprise trigger a sudden loss of muscle tone. A person might collapse mid-conversation or have their knees buckle without warning. These two symptoms are the specific targets of prescription GHB.
In clinical practice, the medication significantly reduces both problems. In one long-term study of patients with narcolepsy and cataplexy, weekly cataplexy episodes dropped from an average of about 26 to roughly 4 per week. Daytime sleepiness scores also improved meaningfully, with higher doses producing greater reductions in sleepiness.
How It Works in the Brain
Prescription GHB (sodium oxybate) is a central nervous system depressant that acts on the same receptor system as GABA, one of the brain’s main calming chemicals. By activating these receptors in the thalamus, a relay station deep in the brain, it triggers slow electrical rhythms that promote deep sleep. This deep, slow-wave sleep is often fragmented in people with narcolepsy, and consolidating it at night appears to reduce daytime symptoms.
The medication also shifts the balance of chemical messengers that control when REM sleep (the dreaming stage) switches on and off. Since cataplexy is essentially REM-related muscle paralysis intruding into waking life, stabilizing that switching mechanism helps prevent episodes.
Two Formulations Available
The original prescription form, Xyrem, is a sodium-heavy liquid. A newer version called Xywav contains 92% less sodium by using calcium, magnesium, and potassium salts of the same active compound. The FDA has recognized this lower sodium content as clinically meaningful for reducing cardiovascular risk, since narcolepsy patients take the medication long-term. Both formulations contain the same active ingredient and are approved for the same conditions. Xywav also carries an additional approval for idiopathic hypersomnia (excessive sleepiness with no identifiable cause) in adults.
Alcohol Dependence Treatment in Europe
Outside the U.S., GHB has a second medical role. A liquid formulation called Alcover is approved in Italy and Austria for treating alcohol withdrawal syndrome and helping people with alcohol dependence maintain abstinence. This use has not been approved by the FDA, so it is not available for this purpose in the United States.
Common Side Effects
The most frequently reported side effects in adult clinical trials were nausea (up to 20% of patients at higher doses), dizziness (15%), and vomiting (11%). Sleepiness, bedwetting, and tremor also occurred more often than with placebo, each affecting 5% to 8% of patients at higher doses. In children and adolescents, bedwetting (19%), vomiting (18%), headache (17%), and decreased appetite (9%) were among the most common reactions. Weight loss was reported in 13% of pediatric patients.
Strict Dispensing Controls
Because GHB has significant potential for misuse, abuse, and dangerous interactions, the FDA placed it in an unusual legal category. When prescribed for narcolepsy, it is classified as a Schedule III controlled substance. The same compound used outside of medical supervision is classified as Schedule I, the most restrictive federal category.
Prescription GHB is subject to a Risk Evaluation and Mitigation Strategy, or REMS, which imposes layers of safety requirements that go well beyond a standard prescription. You cannot pick it up at a regular pharmacy. It is dispensed only through a single specially certified central pharmacy, which ships it directly to patients using overnight delivery with tracking and confirmed receipt. The pharmacy screens every prescription for dangerous drug interactions, particularly with other sedatives and alcohol, and monitors for signs of misuse or diversion. Initial shipments are limited to a one-month supply, with subsequent refills capped at three months.
These restrictions reflect the serious risks of the drug. GHB is a potent CNS depressant, and combining it with alcohol or sedative medications can cause life-threatening respiratory depression. Patients and prescribers must both be enrolled in the REMS program before treatment can begin, and a REMS pharmacist is available around the clock.
How Patients Take It
The medication is taken as a liquid at bedtime, in two separate doses. The first dose is taken at the time the patient gets into bed, and the second dose is taken two and a half to four hours later. Because the drug’s effects come on quickly and strongly, patients need to be lying down and ready to sleep before each dose. This split-dose schedule reflects the drug’s short duration of action and is designed to cover a full night’s sleep while minimizing risk.