Trainers and veterinarians are reminded of their obligations under the provisions of AR64M which prohibits the administration of an intra-articular (“into the joint”) corticosteroid preparation to a Thoroughbred racehorse within 8 Clear Days of a race, official trial or jump-out.
Further, participants are reminded that this enforced stand down period for intra-articular corticosteroids must not be confused with the recommended “withdrawal” time for the particular drug used and/or for the joint injected.
The withdrawal period for a prohibited substance is calculated to ensure a horse is presented clear of the prohibited substance when sampled. In the case of intra-articular injections, the withdrawal period will depend on the corticosteroid used as well as the joint(s) injected.
A recent case (see - Stewards inquiry into Astronomos (GB) sample) involving the detection of triamcinolone acetonide in a race day sample following the intra-articular injection of the drug (in the preparation Kenacort) into the stifle joint just outside the 8 clear days in accordance with AR64M highlights this important issue.
In certain situations, specifically for longer acting corticosteroid preparations such as methylprednisolone and/or for injections into joints other than the carpal (knee) and fetlock joints, the recommended “withdrawal” period may be much longer than the minimum stand down time prescribed by AR.64M.
Therefore, trainers and their veterinarians must carefully consider the circumstances of each particular case before deciding upon the appropriate time of intra-articular injection before competition to ensure that the horse is presented without detectable residues of the corticosteroid administered.