Hundreds of cocaine users are testing whether the legal pill, called modafinil, a medicine already sold to wake up narcoleptics, could help them kick the addiction, and there's early evidence that it may.

In addition to blunting cocaine's notorious cravings, modafinil might also counter the damage that cocaine wreaks on users' brain circuits - damage that in turn fuels the cycle of addiction.

The National Institutes of Health is spending $10.8 million researching modafinil as a potential cocaine treatment. Results from the first of three key clinical trials could arrive by year's end.

Dr. Nora Volkow, director of NIH's National Institute on Drug Abuse told the Associated Press the narcolepsy medicine tops the list of promising potential therapies. It may help restore proper function of a crucial brain chemical, dopamine, that addiction compromises.