Click on this side: https://mayomeds.com/adhd/provigil/ Provigil promotes wakefulness and is used to treat excessive daytime sleepiness caused by narcolepsy, shift work sleep disorder. The Provigil dosage for sleepiness from narcolepsy and other conditions is usually 200 mg per day. Dosage may vary based on your symptoms and other factors. Be sure to take the Provigil dosage your doctor prescribes. The most common side effects of Provigil are: a headache, dizziness, feeling nervous or anxious, back pain, nausea, diarrhea, an upset stomach, sleep problems (insomnia), poor appetite, and a stuffy nose.