"As with any drug, Provigil has side effects. According to the [UK govt], the list is substantial, including nervousness, insomnia, excitation, irritability, tremors, dizziness and headaches. It may also cause "gastrointestinal disturbances", including nausea and abdominal pain, dry mouth, loss of appetite and cardiovascular effects such as high blood pressure, palpitations and tachycardia - a fast heart beat."

http://education.guardian.co.uk/higher/research/story/0,,127...

Still tempting for hitting immediate deadlines, but I'd be very reluctant to use it long-term.