Las Vegas, NV (KTNV) -- Are you looking for a boost of energy to help you get through the day? A prescription pill might help.

Sales of Provigil are up 74% in the last four years.

Provigil is ONLY approved for narcolepsy, sleep apnea and for people who work irregular hours.

However, many other people are now taking it because it is known to boost energy and focus.

The drug has earned the nickname of "Viagra for the brain." And it is quietly being used by military pilots, pro-athletes and pro-poker players.

There are hundreds of websites that talk about the doctor and how to get your doctor to prescribe it. And, some websites say that there are ways to get it without a prescription.

Doctors say that most people on Provigil don't see any side effects although there have been rare cases of life-threatening rashes.

Still, there have not been any studies on the long-term effects of the drug. So, doctors say that if you need more energy, the best bet is to just get more sleep.