ROCKVILLE, MD. - The first drug that is effective for treating cataplexy in patients with narcolepsy appears to be headed for approval after winning support from a Food and Drug Administration advisory committee.
But prescriptions for sodium oxybate (Xyrem) will be restricted by several unusual limitations because of the drug's dark side of abuse and addiction as gamma hydroxybutyrate (GHB), a feature that was highlighted throughout the day-long committee hearing.
Sodium oxybate is the low-profile name that has been coined by the manufacturer for GHB, an increasingly popular "club drug" that has been linked to the deaths of 71 recreational drug users and the addiction of many more, according to expert testimony that was delivered at the hearing.
The two-sided nature of sodium oxybate led to a decidedly schizophrenic public-hearing phase of the committee's session. On one side were the testimonials from several patients with narcolepsy that described how life-changing the drug had been, and how invaluable was its ability to cut the number and severity of their cataplexy attacks. On the other side were two mothers of teenagers who had died as a result of GHB addiction or overdose.
GHB is a powerful CNS depressant that appears to work by improving nighttime sleep. It was readily available in health food stores until 1990, when it was pulled by the Food and Drug Administration (FDA) after several reports charging that abuse had led to respiratory arrest and death. Continued, illicit use led to federal legislation that made GHB a schedule I drug in February 2000. If sodium oxybate/GHB is approved by the FDA, it would be as a schedule III drug.
Because of the drug's abuse potential, it's sponsor, Orphan Medical Inc. of Minnetonka, Minn., has designed a detailed distribution scheme for the drug, in which prescriptions would only be filled by a single specialty pharmacy that would supply sodium oxybate to all patients in the United States. Physicians would be required to confirm any prescriptions written for the drug, after which a limited supply of the medication would be sent directly to the patient using an overnight courier.
Experts estimate that cataplexy attacks affect as many as 25,000 of approximately 135,000 narcolepsy patients in the United States. The advisory committee unanimously rejected excessive daytime sleepiness as a second indication for the drug, which would have made it available to substantially more narcolepsy patients. This indication was rejected based on insufficient evidence for efficacy.
Among the novel restrictions recommended by the advisory committee was a lid on off-label use. …