Background: Armodafinil is a wake-promoting agent developed by Cephalon that was approved in mid-2007 for the treatment of excessive sleepiness associated with narcolepsy, obstructive sleep apnea and shift work disorder. It is the R-enantiomer of the compound modafinil. Like modafinil, the mechanism of action for armodafinil is not fully characterized. Objective: To determine what data are available to support the potential use of armodafinil in clinical settings. Methods: There are limited data on armodafinil available in the public domain, particularly in regard to chemistry and pharmacokinetics/dynamics. Data were reviewed from refereed journals, scientific presentations, and published labeling. Results/conclusion: Clinical trials demonstrated efficacy and safety profiles that were similar to those of the parent compound with wake promotion sustained throughout the day. The longer duration of effect has the potential for improved patient response and compliance but this will require further study. The primary commercial challenge may be the future availability of generic modafinil.