Provigil 200mg tablet is a prescribed medication used in the treatment of narcolepsy, a condition in which there are irregularities in the sleep-wake cycle. Obstructive Sleep Apnea is a condition where the breathing stops for a short period or the breathing is shallow, leading to a lack of sleep at night and daytime sleepiness. It improves wakefulness, helps you to remain awake, and reduces the tendency to nod off during the day, thus restoring the normal sleep cycle.