Armodafinil (NuvigilTM) is an isomer of a drug currently approved by the FDA for the treatment of fatigue secondary to narcolepsy, sleep apnea, and shift work sleep disorder called modafinil (ProvigilTM). There is considerable off label evidence for modafinil's ability to reduce fatigue related to multiple sclerosis, Parkinson's disease, cancer related fatigue, and depression related fatigue. There are preclinical studies showing that modafinil can alleviate fatigue secondary to medication side effects (diazepam, chlorpromazine). This multi-layered evidence base suggests that modafinil may be able to alleviate fatigue regardless of medical illness. Armodafinil now has four completed Phase III FDA regulatory studies revealing that it is well tolerated and effective for fatigue associated with obstructive sleep apnea (Effects of Armodafinil in the Treatment of Residual Excessive Sleepiness Associated with Obstructive Sleep Apnea/Hypopnea Syndrome: A 12-Week, Multicenter, Double-Blind, Randomized,Placebo-Controlled Study in nCPAP-Adherent Adults. Thomas Roth et al. Clinical Therapeutics/Volume 28, Number 5, 2006), shift work sleep disorder, and narcolepsy. Armodafinil is not yet FDA approved. It is felt to be a cleaner, safer, more potent isomer. Theoretically, fatigue is interpreted and possibly dictated centrally and armodafinil's proposed mechanism (similar to that of modafinil) of elevating central histamine activity may allow the brain to interpret a lower fatigue state, thus allowing patients to function better during the day with less peripheral fatigue.