Narcolepsy and cataplexy: not funny
The comic routine is a familiar one: the excessively sleepy person falls asleep at the most inappropriate times, such as during a conversation, or at work, or while driving. For people who really suffer from excessive daytime sleepiness (EDS), though, it's hardly a laughing matter.

EDS can be caused by many things, but in some cases is a symptom of narcolepsy, a brain disorder. Studies have shown that narcolepsy affects between 1 in 1,000-2,000 people in the United States, 1 in 600 in Japan, and 1 in 500,000 in Israel, with estimates of as many as 3 million people worldwide being affected. Similarities in types of symptoms, age of onset, and severity of the disorder have been found across different ethnic groups.

Cataplexy
Research has linked low levels of a brain chemical called hypocretin (orexin) with narcolepsy, and with a symptom that many people with narcolepsy have called cataplexy. Cataplexy involves a sudden, temporary loss of muscle tone. It is often brought on by laughing or being startled. Mild spells or attacks might, for example, cause the jaw or head to drop. Severe attacks can cause the person to collapse on the floor. It lasts anywhere from a few seconds to 25 minutes. Unlike a seizure, the person doesn't lose consciousness. At present, antidepressants such as Tofranil (imipramine) and Prozac (fluoxetine) are used to partially control cataplexy.

The GHB problem
A new medication for cataplexy that is close to U.S. Food and Drug Administration (FDA) approval is Xyrem (sodium oxybate), produced by Orphan Medical. On April 10, 2002, Orphan Medical received notice from the FDA that it is prepared to approve Xyrem but only under special conditions. Why? Because sodium oxybate is also gamma hydroxybutyrate, or GHB, better known as the "date-rape" drug. On the street, GHB is used to incapacitate someone, usually for sexual assault. The drug is colorless and odorless, and its taste is easily masked by putting it in a drink. It knocks the victim unconscious for a few hours and often causes amnesia about what happened, too.

The FDA and law enforcement officials have been naturally concerned about bottles of Xyrem making their way to the street for criminal sale and use. It has been classified as a Schedule I (most restricted) controlled substance. Before approving Xyrem, the FDA required Orphan Medical to devise a risk management program. The result is a special distribution system in which all prescriptions for Xyrem will be filled by one central pharmacy. This limits the chain of people who handle the drug and who receive bottles of it.

Future research
In studies of Xyrem, people with cataplexy often experienced dramatic reductions in the number of spells they had each day. In an effort to relieve or reduce narcolepsy as well, companies are now looking to develop medications that either replace hypocretin or mimic its effects. There is some discussion about narcolepsy being an autoimmune disorder resulting in the destruction of the brain cells that produce hypocretin, so future research will no doubt explore this.

Information for this article was taken from:
- Foreman, J. "A new dawn in therapies for illness tied to narcolepsy." The Boston Globe, April 9, 2002.
- Okun, M. L., Lin, L., Pelin, Z., Hong, S., & Mignot, E. (2002). Clinical aspects of narcolepsy-cataplexy across ethnic groups. Sleep Vol. 25 No. 1, pp 27-35.
- "Orphan Medical Receives FDA Approvable Letter for Xyrem." Press release, April 10, 2002, from Orphan Medical. Available online.
- Siegel, J. M. Narcolepsy. Scientific American, January 2000. Available online

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