Narcolepsy

Shrinkette (http://www.shrinkette.blogspot.com/) recently forwarded me a question about narcolepsy from another blogger. I am posting some info about narcolepsy from the National Sleep Foundation (in italics) along with my comments:
What is narcolepsy?
Narcolepsy is a chronic (long-lasting) neurological (affecting the brain or nerves) disorder that involves your body's central nervous system. The central nervous system is the "highway" of nerves that carries messages from your brain to other parts of your body. For people with narcolepsy, the messages about when to sleep and when to be awake sometimes hit roadblocks or detours and arrive in the wrong place at the wrong time. This is why someone who has narcolepsy, not managed by medications, may fall asleep while eating dinner or engaged in social activities - or at times when he or she wants to be awake.
The major symptoms of narcolepsy are:
Excessive daytime sleepiness is usually the first symptom to appear, and often the most troubling. It is an overwhelming and recurring need to sleep at times when you want to be awake. In addition to sleepiness, key symptoms of narcolepsy can include regular episodes of:
cataplexy - a sudden loss of muscle control ranging from slight weakness (head droop, facial sagging, jaw drop, slurred speech, buckling of knees) to total collapse. It is commonly triggered by intense emotion (laughter, anger, surprise, fear) or strenuous athletic activity. Most persons with narcolepsy have some degree of cataplexy.
sleep paralysis - being unable to talk or move for a brief period when falling asleep or waking up. Many persons with narcolepsy suffer short-lasting partial or complete sleep paralysis.
hypnagogic hallucinations - vivid and often scary dreams and sounds reported when falling asleep. People without narcolepsy may experience hypnagogic hallucinations and sleep paralysis as well.
automatic behavior - familiar, routine or boring tasks performed without full awareness or later memory of them.
Cataplexy is one of the main symptoms that a sleep specialist looks for in diagnosing narcolepsy- this symptom is specific to narcolepsy. Unfortunately, it can take up to 10 years after sleepiness first occurs for cataplexy to develop. Excessive daytime sleepiness is common to a wide variety of sleep disorders, including obstructive sleep apnea.
The diagnosis of narcolepsy:
In addition to a medical history and physician examination, a diagnosis is made from polysomnogram tests in an overnight sleep laboratory to measure brain waves and body movements as well as nerve and muscle function. A diagnosis also includes the results of the Multiple Sleep Latency Test (MSLT), which measures the time it takes to fall asleep and to go into deep sleep while taking several naps over a period of time.
The major medications for sleepiness are the stimulants and Modafinil. Cylert is not used anymore due to liver toxicity:
Common stimulants include: dextroamphetamine sulfate (DexedrineTM), methylphenidate hydrochloride (RitalinTM), and pemoline (CylertTM). Methamphetamine hydrochloride (DesoxynTM) is prescribed less frequently for narcolepsy.
Some of the most common side effects of stimulants are headache, irritability, nervousness, insomnia, irregular heart beat, and mood changes.
A wake-promoting drug, modafinil (ProvigilTM) was approved by the U.S. Food and Drug Administration (FDA) in 1999 for use in treating the excessive daytime sleepiness associated with narcolepsy. It does not act as a stimulant for other body systems and studies have shown that modafinil is effective in improving alertness with few side effects and low abuse potential.
Modafinil is less effective than the stimulants. It is often better tolerated, though it can cause headaches. Modafinil interacts with birth control pills and decreases their efficacy.
Antidepressants are usually used to treat cataplexy:
Several classes of antidepressants are prescribed to treat cataplexy, hypnagogic hallucinations and sleep paralysis. One class, multicyclics, includes imipramine (TofranilTM), desimpramine (NorpraminTM), clomipramine (AnafranilTM), and protriptyline (VivactilTM). Another class are selective serotonin re-uptake inhibitors (SSRIs). These include fluoxetine (ProzacTM), paroxetine (PaxilTM), and sertraline (ZoloftTM).
The multicyclics (tricyclics) can have cardiac side effects, including fast heart rate and heart arrhythmias. They can also cause dry mouth and constipation. They are more effective, in my opinion, than the SSRI's for cataplexy. The only SSRI that has been well studied for cataplexy is Prozac. The tricyclics increase norepinephrine and serotonin levels. The SSRI's increase serotonin levels; Prozac also has a norepinephrine-increasing metabolite. Norepinephrine-increasing effects are thought to be necessary for treatment of cataplexy. I am not aware of evidence that the serotonin selective reuptake inhibitors (other than prozac) are effective for cataplexy (I'd be interested in hearing any comments on this).
Xyrem is a relatively new drug for cataplexy; it also decreases sleepiness:
Sodium oxybate (XyremTM) is the first and only FDA-approved medication for the treatment of cataplexy associated with narcolepsy. It produces consolidation of sleep and improvement of disturbed nighttime sleep characteristic of narcolepsy. It is sedating and should only be used at night. Xyrem is a Schedule III controlled drug substance with abuse potential that is available by prescription.
That's it about narcolepsy today; more later.