TUESDAY, June 5, 2001 (HealthDayNews) -- The government may approve a promising new treatment for narcolepsy, but the therapy would be closely watched: It's a chemical cousin of the "date rape" drug outlawed last year.
A panel of sleep experts for the Food and Drug Administration (FDA) meets Wednesday to discuss the drug to help narcoleptics, whose neurologic disorder can make them fall asleep in mid-sentence.
The drug called is called Xyrem. Its active ingredient is gamma-hydroxybutyric acid (GHB), a controlled substance known as the "date-rape" drug. GHB has been linked to at least 71 deaths and an estimated 5,500 emergency room visits for overdoses.
GHB joined the list of Schedule I controlled substances in 2000 under the Date-Rape Drug Prohibition Act. The drug, and precursor chemicals like GBL that the body converts into GHB, can kill by suppressing the central nervous system.
Although many deaths have been linked to the combination of GHB and alcohol, experts say the compound is deadly on its own. GBL has been sold over the Internet as "blue nitro," "liquid x," "revitalize plus" and other aliases.
Xyrem, made by Orphan Medical of Minnetonka, Minn., would be the first in a new class of narcolepsy drugs to treat both cataplexy -- a sudden loss of muscle control -- and excessive daytime sleepiness (EDS). Current therapies include stimulants like Ritalin and amphetamines for daytime drowsiness, and antidepressants for cataplexy. However, many patients don't respond well to these drugs.
Xyrem, or sodium oxybate, extends the time that patients spend in slow-wave, restorative phases of sleep, which narcoleptics sorely lack. Studies of the drug showed a significant improvement in daytime sleepiness, and up to a 70 percent reduction in bouts of cataplexy, which often sets in during times of positive emotion like hearty laughter. Side effects of the drug in clinical trials included dizziness, nausea, headaches, sleepwalking and urinary incontinence during sleep, or enuresis.
The FDA granted Orphan Medical an expedited review for Xyrem last October, but the company asked for and received an extension of the review earlier this spring.
Narcolepsy affects 100,000 to 125,000 Americans, of whom roughly 75,000 suffer symptoms of cataplexy. Last year, Stanford University researchers found that most patients with narcolepsy lack the brain protein hypocretin, which appears to help promote wakefulness.
Juliette Faraco, a Stanford researcher studying hypocretin's role as a brain messenger molecule, says narcolepsy appears to be an autoimmune disorder similar to diabetes, in which the body turns against insulin-producing islet cells in the pancreas. "It would appear that some people are predisposed to having their body attack those cells" that make hypocretin, Faraco says.
Orphan Medical declined to comment on the upcoming hearing.
Deborah Zvosec, an emergency medicine expert at Hennepin County Medical Center, in Minneapolis, who has studied GHB abuse, says she and her colleagues have "very grave public health concerns" about the potential approval of Xyrem.
"We are very concerned about people getting access to [Xyrem] for the purposes of abuse," says Zvosec, who plans to testify before the FDA panel Wednesday. Inadequate control over how the medication is prescribed could allow people to obtain it for pleasure, she says.
Zvosec says she's worried that Xyrem might become another OxyContin, a potent painkiller co-opted by recreational drug users that has been blamed for scores of deaths nationwide. However, unlike that drug, researchers and law enforcement officials know very little about the abuse of GHB, she says.
Still, Jerome Siegel, a narcolepsy expert at the University of California at Los Angeles, says Xyrem's illegal cousin shouldn't deter the FDA from approving the legal version. "I think it's a very valuable drug for certain patients, and it's unfair to penalize them because others are abusing it," says Siegel, who is also chief of neurobiology research at the Department of Veterans Affairs Medical Center at Sepulveda.
Niss Ryan, vice president of Narcolepsy Network, a national support group for patients with the disorder, agrees. She says, "People who have severe cataplexy really have nowhere else to turn. Other things help some, but they don't really control" the problem.
Ryan says network members are sensitive to the potential abuse of Xyrem by GHB addicts. However, she says since getting the illegal drug is relatively easy, rejecting Xyrem would only punish patients.
Although the FDA isn't bound by its panels' advice, the agency rarely rejects their recommendations.
What To Do
For more on narcolepsy, check the Narcolepsy Network or the Stanford Center for Narcolepsy.
To learn more about recreational use of GHB, visit the Drug Enforcement Administration.
