Modafinil has been shown to improve wakefulness in patients with excessive sleepiness associated with shift work sleep disorder, narcolepsy, and obstructive sleep apnea. Modafinil was well tolerated in 9-week, randomized, double-blind, placebo-controlled studies in these patient populations. Adding a 200 mg midday dose of modafinil improved the efficacy of once-daily dosing regimens in...