Modafinil

Marketed as a wakefulness promoting agent, modafinil belongs to the group of medicines known as central nervous system (CNS) stimulants, which is commonly used to promote wakefulness and reduce excessive daytime sleepiness in patients with narcolepsy, obstructive sleep apnea, hypopnea syndrome, shift-work sleep disorder or circadian rhythm sleep disorder. Besides, recently studies have showed that modafinil may be effective to help cocaine addicts fight against their addiction.
The sleepiness-preventing effects of modafinil functions by stimulating certain parts of the brain, in which the neurons are activated by modafinil. It binds to the dopamine reuptake pump so as to inhibit the reuptake of dopamine from the cell, while the extracellular dopamine increases, thus preventing drowsiness and keeping people from falling asleep.