Provigil 200mg is commonly used to treat daytime sleepiness caused by conditions such as narcolepsy, sleep apnea, and shift work sleep disorder. It works by increasing the activity of certain chemicals in the brain that helps to regulate wakefulness and alertness. If you suffer from daytime sleepiness, Provigil may be able to help you stay awake and alert during the day. Overall, Provigil can be a helpful medication for people who struggle with daytime sleepiness caused by a sleep disorder. However, it is important to use the medication responsibly and under the guidance of a healthcare professional.