The Kentucky Equine Drug Research Council is recommending horsemen discontinue the use of naproxen at least five days before a horse is scheduled to run to avoid facing a penalty if the horse tests positive for the drug on race day. Naproxen is a non-steroidal anti-inflammatory drug (NSAID) and a potent pain reliever. The drug is often prescribed for lameness, musculoskeletal pain from soft tissue injury, muscle soreness, and bone and joint problems. Connie Whitfield, chairwoman of the KEDRC and the vice-chair of the Kentucky Horse Racing Authority, said the advisory guideline, which will go before the full KHRA at its April 17 meeting. She said the new recommendation regarding naproxen was issued due to the problematic nature of the drug and its withdrawal time.Recent studies have indicated naproxen accumulates in tissue, is metabolized and excreted extremely slowly, and can remain in a horse at an elevated residual level even when use of the drug was discontinued more than 48 hours before race day. The newly created drug rules in Kentucky authorize the use of one of three NSAIDS not less than 24 hours before the time the horse is to race. These three NSAIDS are Phenylbutazone, Flunixin, and Ketoprofen. The drug rule also states that all other NSAIDS must be administered at least 48 hours before the race in which the horse is entered. Under Kentucky guidelines, naproxen, which is a Class C drug, is listed under the state's penalty guidelines but is not among the drugs listed with withdrawal guidelines. An informational meeting for trainers, veterinarians, and owners concerning the use of naproxen is being planned for Wednesday at Keeneland.