Provigil is a prescription medication It is most often used to treat excessive sleepiness caused by narcolepsy, obstructive sleep apnea, and shift work. Provigil belongs to the class of drugs called stimulants. It comes as 100 mg and 200 mg oral tablets. It is easy to use and buy Provigil online with any doctor's prescription. It is important to take Provigil exactly as prescribed by your doctor. The usual recommended dose for adults is 200 mg taken orally once a day in the morning. If you are using Provigil to treat shift work sleep disorder, you should take it one hour before the start of your shift. Provigil can be taken with or without food. It is important to follow the prescription guidelines and talk to your doctor about any concerns or questions you may have regarding its use.