E! Online reported Tuesday that Williamson County prosecutors allege McCready presented a false prescription for OxyContin at a Brentwood, Tenn., pharmacy Feb. 12, paid for the drug and left.
The singer of "A Girl's Gotta Do What a Girl's Gotta Do" was arrested Aug. 5 at her home near Nashville and charged with prescription drug fraud.
A fan Web site, mindymccready.com, said McCready told WYUU-FM in Tampa that although her physician wrote the prescription and that it was legal, the pills were not for her.
"I am not addicted to any drugs. I am not on any painkillers," she said. "So, that's the truth. I just want all the fans out there to know that I'm okay. I'm not sick in any way."