Modalert 200mg is a medication used to promote wakefulness in people with extreme sleepiness during the day. The medicine may cause side effects, including headache, dizziness, nausea, nervousness, agitation, and difficulty sleeping. Modafinil was first approved for use as a treatment for narcolepsy. In the same year, it was approved to treat excessive sleepiness during the daytime in patients with narcolepsy and hypersomnia.