Treatment

Stimulants can have unpleasant side effects, including:

• Weight loss
• Dizziness
• Nausea
• Changes in blood pressure and rapid heartbeat
• Headache

There are some differences between these drugs:

• Methylphenidate, which is the standard drug for treating attention deficit hyperactivity disorder, is safer than dextroamphetamine. Small studies suggest that high doses may help avert cataplexy, although more research is needed to confirm this effect. Psychosis from overdose is very rare. Psychologic dependence can occur, but abuse has not been reported in children who have taken it for years.
• Dextroamphetamine has more severe side effects than methylphenidate. These include mood changes and jerky muscle movements. Prolonged use may cause serious depression. Overdose, which can occur at doses of only 100 to 500 mg, can cause psychosis and even death. This drug should not be used during pregnancy. There is also a risk for addiction and abuse.

Stimulants should be avoided or only taken under a doctor's guidance in people with heart disease, hyperthyroidism, glaucoma, anxiety disorder, and high blood pressure.

These drugs become ineffective if used continuously, and patients are advised to take a drug holiday one day a week or to withdraw gradually and resume treatment at a lower dose. Patients should not engage in activities that require being awake (such as driving) during withdrawal.

Drug Treatments for Cataplexy

Sodium oxybate (Xyrem). Sodium oxybate (Xyrem), also referred to as gamma hydroxybutyrate (GHB), helps reduce the frequency of cataplexy attacks and improve daytime sleepiness. It takes about 4 weeks for significant benefits, which reach their peak at about 8 weeks. Food intake can affect it, so patients are advised to take it at a regular time after the evening meal.

In 2002, the FDA approved Xyrem for treatment of cataplexy associated with narcolepsy. However, the FDA placed tight restrictions on its use. Although the drug appears to be effective and safe when used for narcolepsy, it has a history of illegal and "date-rape" use, with street names such as "Grievous Bodily Harm" or "Liquid Ecstasy." (The last term is not to be confused with "Ecstasy," another street drug with different effects.) In high doses, it can cause dependence over time. In addition, very serious side effects -- including seizures, coma, respiratory arrest, and death -- have been reported in people who abused it. Trials of Xyrem, however, have not reported these effects with the doses used in treatment for cataplexy. Patients still report side effects, although they tend to be mild. They include nausea, headache, dizziness, urine leakage, and sleepwalking.