
But the Nevada State Athletic Commission put a halt to the fight after Credeur's pre-fight drug test revealed traces of the prescription drug Adderall, which is mostly used to treat attention-deficit disorder. Commission head Keith Kizer explains that Credeur was honest about using the medicine and agreed to stop taking it, but that wasn't enough:
"Unfortunately, the drug was still in his system and he's still positive, so he was unable to get cleared to fight," Kizer said, per UFC's official web site.
Adderall is banned for two reasons: First, it can impair cardiovascular functioning during a high-stress activity like engaging in a mixed martial arts fight. And second, some experts believe its stimulant properties make it a performance-enhancing drug.
Credeur will not be disciplined because he admitted to using the medicine and agreed to stop taking it as soon as he learned that it was banned. Credeur's case was the second time in as many days that an athlete's use of ADD medication became an issue: On Friday, Olympic sprinter Justin Gatlin won a court case he brought alleging that his suspension for using ADD medicine violated the Americans with Disabilities Act.