Modafinil is an oral drug that is used for improving wakefulness in patients with excessive sleepiness. It is similar to armodafinil (Nuvigil). Like amphetamines, modafinil promotes wakefulness by stimulating the brain. The exact mechanism of action of modafinil is unknown. It may work by increasing the amount of dopamine (a chemical neurotransmitter that nerves use to communicate with each other) in the brain by reducing the reuptake of dopamine into nerves. Modafinil was approved by the FDA in December 1998.