The drug known as modafinil is a prescription drug used by doctors to enhance wakefulness in their patients. The drug is taken orally and is used mainly in patients who mainly suffer from excess sleep. The medication works by either increasing the amount of dopamine or preventing the amount of dopamine re-uptake in the body. Research into this drug indicates that modafinil,like its predecessor adrafanil, works well with few or no side effects. It is also well tolerated by the body. It is used by medical health practitioners to treat sleep disorders that result from conditions such as obstructive sleep apnea and narcolepsy.