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| T02-31 | Media Inquiries: 301-827-6242 |
| July 17, 2002 | Consumer Inquiries: 888-INFO-FDA |
The Food and Drug Administration today approved Xyrem (sodium oxybate or gamma hydroxybutyrate, also known as GHB) for treating a small population of patients with narcolepsy who experience episodes of cataplexy, a condition characterized by weak or paralyzed muscles. Because of safety concerns associated with the use of the drug, the distribution of Xyrem will be tightly restricted.
In the early 1990s GHB was marketed purporting to be a dietary supplement for enhancing athletic performance and sexual activity and for inducing sleep. It was also abused as a recreational drug and is well-known for use in date rape. As a result of a number of serious adverse events, including death, FDA intervened to prohibit marketing of GHB.
Xyrem has been designated as a Schedule III Controlled Substance for medical use, meaning it cannot be sold, distributed, or provided to anyone other than for its prescribed use. Illicit use of Xyrem will be subject to penalties under Schedule I, the most restrictive schedule of the Controlled Substances Act.
FDA approved Xyrem based on the results of two controlled clinical trials that showed that use of the drug reduced the number of cataplectic attacks compared to placebo. About 85 percent of these patients were also treated with central nervous system stimulants. A total of 448 patients were treated with Xyrem in clinical trials. Xyrem must be taken at bedtime and then again 2 1/2 to 4 hours after the beginning of sleep.
Narcolepsy affects about 120,000 people in the United States. This rare condition causes an irresistible tendency to fall asleep even in unlikely circumstances such as in the middle of a conversation or at a meal. Cataplexy, a symptom of this condition, is a sudden loss of muscular control and weakness usually triggered by emotions such as amusement, anger or excitement, and is estimated to affect about 20,000 to 50,000 individuals. The effects of cataplexy range from dropping of the jaw and slumping of the head, to buckling of the legs and even collapse of the whole body. These effects can last for a few seconds or up to many minutes.
Due to serious concerns and adverse events associated with the use of Xyrem, including some events that resulted in death, FDA has worked with the drug's manufacturer, Orphan Medical Inc., to design a comprehensive risk management program. The program includes limited distribution, physician education, patient education, the creation of a patient and physician registry, and detailed patient surveillance. Under the program, prescribers and patients will be able to obtain the product only through a single centralized pharmacy. The pharmacy will send Xyrem to patients only after their doctors have provided instruction on the safe and effective use of the drug and after the patients have read the information provided about the drug. Doctors will also be urged to see their patients at least every three months. Doctors are also expected to report all serious adverse events to the manufacturer by calling 1-866-XYREM-88 (1-866-997-3688).
Side effects associated with Xyrem include confusion, depression, nausea, vomiting, dizziness, headache, bedwetting, and sleepwalking. Abuse of Xyrem could also lead to dependence, i.e, craving for the medicine, and severe withdrawal symptoms.
A Medication Guide, a special patient information brochure required by FDA, further advises patients about proper use, administration and disposal of the drug. Patients who have further questions are advised to talk to their doctor or advised to call the central pharmacy at the toll free number.
Xyrem is being approved with Orphan Drug status, which is available for products for patient populations of 200,000 or fewer. Sponsors of such products receive inducements that include seven-year marketing exclusivity, tax credit for the product-associated clinical research, and research design assistance by FDA.
Orphan Medical Inc., Minnetonka, Minn., will distribute the drug.
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