The possession or transportation of any drug or chemical within the racing enclosure of a racing facility under the jurisdiction of a commission is prohibited except for those permitted by regulations of the commission or those justified by a bona fide veterinarian’s prescription with a complete statement of uses and purposes on the container. Depending upon whether such prescription is for a horse or a greyhound, a copy thereof shall be filed with the stewards for horse racing or the judges for greyhound racing, as the case may be.