Modafinil is a potent wakefulness-promoting agent, often classified as a eugeroic, that is FDA-approved to treat excessive daytime sleepiness associated with conditions like narcolepsy, obstructive sleep apnea, and shift work disorder.Unlike traditional stimulants, it targets specific neurotransmitter systems in the brain—including dopamine, histamine, and orexin—to foster a state of alert wakefulness without the intense "jittery" sensations or the sudden "crash" typical of amphetamines.