A prescription medication called Modalert 200 USA is used to treat narcolepsy, a condition in which there are disruptions in the sleep-wake cycle. When a person has obstructive sleep apnea, their breathing either stops abruptly or is shallow, which causes them to be sleepy during the day and lack of sleep at night. It increases wakefulness, enabling you to stay awake longer and lessening your propensity to fall asleep during the day, thereby reestablishing the regular sleep-wake cycle.