by Natalie Voss
Since its 2001 foundation, the Racing Medication and Testing Consortium has made strides toward its goals of a nationally uniform set of medication rules and rigorous state drug testing lab accreditation. In December, RMTC anticipated the number of states working under its recommended list of therapeutic medication thresholds would increase from four at the start of 2014 to 16 by early 2015. The change was a 300 percent improvement in the span of a year toward the consortium’s goal to get states on the same wavelength.
But since the therapeutic medication schedule first became news, the consortium has added a few substances to the list of drugs it considers acceptable for use in racehorses outside of race day. So how does the group keep multiple jurisdictions on the same page when the table of contents shifts from time to time? RMTC executive director Dr. Dionne Benson says it can be a process.
“I think it depends on the state,” she said. “Some states adopt the list and when the list is updated by RCI
“I realize that causes them some stress and consternation, but at the end of the day we’ve got to get to the right place for everyone.”
The drugs on that list now total 26 medications, and the RMTC provides a recommended withdrawal time and testing threshold for each. The challenge has been to find a testing limit that allows veterinarians and trainers to treat horses for illness or injury without leaving the door open for drugs to modify performance or risk safety. To accomplish this task, the RMTC calls upon a scientific advisory board of 15 regulatory veterinarians, private practitioners, chemists, and others to review existing research and commission new studies when necessary.
The panel might work from a blood concentration that’s understood to be appropriate and construct a timeframe for withdrawal, or it may take a suggested withdrawal time and determine a threshold unlikely to produce a positive test within that timeframe. In the case of a research-derived threshold, the panel uses a small herd of exercised research horses, giving them a dose of the drug in question and monitoring the levels in blood for a set period of time. The group then applies a statistical test called a tolerance interval to factor in a reasonable amount of leeway for differences in individual metabolism and other factors. So, in a study of isoflupredone, a corticosteroid, the regulators found that the most a horse had in its system after a 20 mg joint injection was around 18 picograms per millileter of blood seven days after administration. Taking into account individual differences in metabolism and other factors, the confidence interval test suggested a 91.2 picogram per milliliter threshold, which was rounded up to 100.
The process can be a slow one; Benson said that in the case of one drug, the ulcer medication ranitidine, new research was required to determine the best withdrawal guidelines. The study was started in early 2014, samples analyzed by late 2014, and Benson hopes the report will be part of the RMTC’s March 2015 board meeting. From there, the board’s approval of the information would send the suggestions to the RCI for its April meeting. The soonest a guideline could be approved by RCI would be July. All of that comes before a state racing commission or legislature can approve the threshold and withdrawal guideline.
There is also a lack of understanding among some practitioners about what it means to see a drug on the RMTC’s therapeutics list. It doesn’t mean that all other substances are banned from the horse’s system. Benson clarified that the consortium is concerned only with those that “operate on the mammalian system,” meaning that antibiotics, anti-virals, and dewormers’, even though they’re not on the list, can be given under the rules because they act on the bacteria, viruses, or parasites in the horse’s system. (The exception would be those which are combined with a drug that does operate on the horse’s body, like procaine penicillin. The procaine is a local anesthetic designed to reduce discomfort at the site of injection.)
As for the RMTC’s outlook on 2015, Benson expects to see more progress toward this uniform policies goal. She’s also hoping that the consortium will make some headway in education.
“Certainly we have not been immune to criticism this year, and most of it is because we haven’t done the best job of communicating these policies throughout the industry once we’ve gotten them passed at the commission level,” said Benson. “We need to do a better job of educating horsemen and trainers.”