Modafinil (Provigil), a benzhydryl sulfinylacetamide non-amphetamine stimulant that has been used in Europe since 1995, has now been approved by the FDA for treatment of excessive daytime sleepiness associated with narcolepsy.

Modafinil (Provigil - Cephalon; Alertec - Draxis in Canada), first approved by the FDA in 1999 for treatment of excessive daytime sleepiness associated with narcolepsy (Medical Letter 1999; 41:30), has now also been approved for treatment of patients with excessive sleepiness due to obstructive sleep apnea/hypopnea syndrome (OSAHS) or shift work sleep disorder (SWSD) (DSM-IV, text revision, Washington, DC: American Psychiatric Association, 2000, page 622).

Armodafinil (Nuvigil – Cephalon), the R-enantiomer of the non-amphetamine stimulant modafinil (Provigil – Cephalon; Alertec – Shire in Canada), is being promoted directly to the public for treatment of excessive daytime sleepiness associated with shift work.

The FDA has approved pitolisant (Wakix – Harmony), a histamine-3 (H₃)-receptor antagonist/inverse agonist, for treatment of excessive daytime sleepiness (EDS) or cataplexy in adults with narcolepsy. It is the first H₃-receptor antagonist/inverse agonist to become available in the US and the first non-controlled substance to receive FDA approval for these indications. Pitolisant has been available in Europe since 2016.

Gamma hydroxybutyrate (GHB), a central-nervous-system depressant notorious for its use in "date rape", was approved by the FDA in 2002 as sodium oxybate (Xyrem - Jazz Pharmaceuticals) for oral treatment of cataplexy in patients with narcolepsy. Now it has also been approved for treatment of excessive daytime sleepiness (EDS) in these patients. Xyrem is a Schedule III controlled substance.

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Xywav (Jazz), an oral solution that contains calcium, magnesium, potassium, and sodium oxybates, has been approved by the FDA for treatment of idiopathic hypersomnia in adults. It is the first drug to be approved in the US for this indication. Xywav was approved in 2020 for treatment of excessive daytime sleepiness or cataplexy in patients ≥7 years old with narcolepsy. It contains about 92% less sodium than sodium oxybate oral solution (Xyrem), which has been available in the US for years for use in patients ≥7 years old with narcolepsy.

The FDA has approved use of gamma hydroxybutyrate (sodium oxybate is the official generic name; Xyrem - Orphan Medical) for oral treatment of cataplexy in patients with narcolepsy. Gamma hydroxybutyrate (GHB), a metabolite of gamma-aminobutyric acid (GABA), is a central-nervous-system depressant marketed in Europe for use in general anesthesia. In recent years it has been notorious for its use in "date-rape" (Medical Letter 2002; 44:21). Xyrem is a Schedule III controlled substance.

The FDA has approved solriamfetol (Sunosi – Jazz), a dopamine and norepinephrine reuptake inhibitor (DNRI), to improve wakefulness in adults with excessive daytime sleepiness (EDS) associated with narcolepsy or obstructive sleep apnea (OSA). Pitolisant (Wakix), an H3-receptor antagonist/inverse agonist recently approved by the FDA for treatment of excessive daytime sleepiness in patients with narcolepsy, will be reviewed in a future issue.

Many drugs can cause psychiatric symptoms, but a causal connection is often difficult to establish. Psychiatric symptoms that emerge during drug treatment could also be due to the underlying illness, previously unrecognized psychopathology, or psychosocial factors. The withdrawal of some drugs can cause symptoms such as anxiety, psychosis, delirium, agitation or depression.

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