The following information may help to address your question:
Modafinil is the first-line treatment for idiopathic hypersomnolence due to its better risk/benefit ratio. This medication has proved clinically useful in the treatment of narcolepsy and other causes of excessive daytime sleepiness such as idiopathic hypersomnolence. It is a psychostimulant that enhances wakefulness and vigilance, but its pharmacological profile is notably different from the amphetamines, methylphenidate (Ritalin), or cocaine. Modafinil is less likely to produce side effects such as jitteriness, anxiety, or excess locomotor activity or lead to a hypersomnolent rebound effect. It is long-acting, the normal elimination half-life of modafinil in humans is between 12-15 hours.
For more information about modafinil, visit the following link to a page from the eMedicine Web site. http://emedicine.medscape.com/article/291699-treatment