RMTC Makes Withdrawal Time Recommendations

The Racing Medication and Testing Consortium board of directors has recommended withdrawal guidelines and plasma thresholds for a bronchodilator, a muscle relaxant, and four anabolic steroids.

According to a release from RMTC, the scientifically identified withdrawal guidelines and plasma thresholds are for the short-acting bronchodilator glycopyrrolate, the muscle relaxant methocarbamol, and four anabolic steroids, three of which are endogenous (naturally occurring) in the horse. A recommendation for the non-steroidal anti-inflammatory medication firocoxib has also been approved pending resolution of one outstanding issue, according to the release. The RMTC’s action was based on the recommendation of its scientific advisory committee

"Administration studies on these medications were developed and funded by the RMTC over the past few years in an effort to provide horsemen and practicing veterinarians with withdrawal guidelines that will enable the therapeutic use of these medications without compromising the integrity of racing competition or the welfare of our human and equine athletes," Dr. Rick Arthur, chair of the RMTC scientific advisory committee and equine medical director for the California Horse Racing Board, said in a statement.

"The results of these studies have been eagerly anticipated by the industry, and we will continue to conduct important research on other therapeutic medications that are commonly used in managing the health of racehorses."

The specific recommendations, made at board’s Oct. 12 meeting at the University of California-Davis on are:

--Glycopyrrolate: Threshold concentration of 3.5 picograms/ml in serum or plasma, which regulates a 24-hour withdrawal guideline for a single, intravenous total dose of 1 mg.

--Methocarbamol: Threshold concentration of 1 nanogram/ml, which regulates a 48-hour withdrawal guideline for a single intravenous dose of 15 mg/kg.

--Firocoxib: Threshold concentration of 40 nanograms/ml in serum or plasma, which regulates a 7-day withdrawal guideline when administered at the FDA-approved label dose, pending a review of clinical effects by the RMTC Scientific Advisory Committee.

--Boldenone: Screening limit no greater than 100 pg/ml in serum or plasma with a confirmatory threshold no greater than 25 pg/ml for all horses regardless of sex, which regulates an 82-day withdrawal time.

--Nandrolone: Screening limit no greater than 100 pg/ml in serum or plasma with a confirmatory threshold no greater than 25 pg/ml for geldings, fillies and mares, which regulates a 35-day withdrawal time. Male horses other than geldings will not be tested for nandrolone in blood.

--Stanozolol: Screening limit no greater than 100 pg/ml in serum or plasma with a confirmatory threshold no greater than 25 pg/ml for all horses regardless of sex, which regulates a 47-day withdrawal time.

--Testosterone: Screening limit no greater than 100 pg/ml in serum or plasma with a confirmatory threshold no greater than 25 pg/ml for geldings, fillies and mares and a confirmatory limit of 2 mcg/ml for male horses other than geldings, which regulates a 30-day withdrawal time.

In addition, the RMTC release said the board approved a plasma threshold of 10 micrograms/ml for DMSO, which would allow for the use of DMSO as a topical leg paint but would not allow for the oral or intravenous administration of the drug. The board also recommended that DMSO be reclassified by the RCI drug testing standards and practices committee to a Class 4 substance when appearing in samples in excess of the threshold concentration.

Based on a report provided by the Scientific Advisory Committee, the RMTC board expects to be able to issue recommendations for acepromazine, pyrilamine, mepivacaine, lidocaine, procaine and butorphanol at its next full meeting in March 2011, according to the release.

Also at the meeting, RMTC executive director Dr. Scot Waterman estimated that by the end of 2011, 11 out of the 19 laboratories that conduct drug testing will be accredited to ISO 17025 standards. He also reported three additional laboratories have expressed an interest in becoming RMTC-accredited as a result of a presentation by RMTC vice chair Alan Foreman’s remarks at the Jockey Club Round Table Conference in August.

In other RMTC business, according to the release:

--Board members received updates on funded research for several potential doping agents and a progress report on research on corticosteroids.

--Dr. Heather Knych, whose work was funded by the RMTC post-doctoral research fellowship program, presented a summary of her ongoing corticosteroids research.

--The RMTC will develop a penalty structure for the 2ug/ml threshold limit for phenylbutazone to recommend to the ARCI for their consideration at the next RMTC board meeting.

The RMTC consists of 25 racing industry stakeholders and organizations that represent Thoroughbred, Standardbred, American Quarter Horse, and Arabian racing.

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