Buy Provigil Online is a prescription medication approved to improve wakefulness in adults suffering from narcolepsy, obstructive sleep apnea, or shift-work sleep disorder. The most common Provigil dosages are 100 mg and 200 mg tablets, taken in the morning or before a work shift as directed by a healthcare provider. Doctors may adjust doses based on individual response and medical Common Provigil side effects include headache, nervousness, nausea, and insomnia. This medication should never be used without professional guidance. Provigil 100 mg and Provigil 200 mg tablets must be taken only as prescribed. Always consult your doctor before changing your dose, starting, or stopping treatment.