(WHAS11) -- Kentucky horse racing regulators say no traces of a powerful painkiller were found in samples taken from horses running in this year's Kentucky Derby.
The Derby horses were tested for dermorphin, a substance more powerful than morphine.
An outbreak of positive tests for the painkiller at Louisiana tracks has resulted in suspensions for trainers.
The announcement follows a story done by the New York Times that says Derby and Preakness winner I'll Have Another was treated with painkillers before the Belmont. The colt was retired the day before the race due to an injury.