New Mid-Atlantic Advisory regarding the use of Methylprednisolone Acetate (Depo-Medrol) and Procaine Penicillin

New Mid-Atlantic Advisory regarding the use of Methylprednisolone Acetate (Depo-Medrol) and Procaine Penicillin

This Advisory addresses concerns that have recently been expressed by horsemen and veterinarians regarding compliance with the uniform drug testing thresholds and guidelines for the use of Methylprednisolone Acetate (Depo-Medrol) and Procaine Penicillin. The regulators from the Mid-Atlantic racing states met on July 1, 2015 and announce the following Advisory.

The testing threshold for methylprednisolone acetate (Depo-Medrol) is 100 pg/ml plasma. This testing threshold is based upon the administration of a total dose of 100 mg methylprednisolone as methylprednisolone acetate in one articular space. The recommended withdrawal time for this administration is a minimum of at least 21 days, but there is a footnote warning that intramuscular (IM) administrations can result in plasma concentrations that can exceed the testing threshold for weeks or months. It is important to understand that the testing threshold can be exceeded if there is: 1) an IM injection; 2) an injection in more than one articular space, 3) a different formulation (e.g., compounded) of methylprednisolone, and 4) an injection into a subcutaneous space, i.e. not injecting into the right spot. This is of particular concern when injecting stifles and hocks, as a portion of the medication often is inadvertently deposited into tissues outside the joint capsule. It is important to understand that when a portion of this drug is placed outside the joint capsule of any joint, an intra-muscular or subcutaneous injection will be the result.
Accordingly, it is recommended that 1) Depo-Medrol should not be administered to any horse a trainer wishes to race in the Mid-Atlantic region – New York, New Jersey, Pennsylvania, Delaware, Maryland, West Virginia and Virginia; and 2) a trainer who chooses to race a horse that has been treated with Depo-Medrol despite this warning should, at his/her expense, get the horse tested prior to entry to ensure that the horse will test below the testing threshold of 100 pg/ml plasma. The testing threshold of 100 pg/ml plasma will be enforced.

The current Guideline for Procaine penicillin requires the reporting of the administration of this drug to the Racing Commission and a mandatory surveillance of the horse for 6 hours prior to the race if the trainer wishes to race the horse. The purpose of the quarantine is to ensure against a nerve block. The Guideline, however, does not specify how long after administration of procaine penicillin the reporting and mandatory surveillance requirements must be followed.
Effective immediately, only Procaine Penicillin administrations within 30 days of a race need be reported to the Racing Commission. The surveillance requirement remains in effect. The Racing Commission or the racetrack, as the case may be, will provide a security guard for the horse at the owner/trainer’s expense. Please note that the testing threshold for Procaine Penicillin is 25 ng/ml plasma regardless of the surveillance requirement and this testing threshold will be enforced.