By: Matt Hegarty

LEXINGTON, Ky. – Stewards in Kentucky have issued a ruling rescinding a 40-day suspension handed down last year to trainer Mike Maker for a post-race positive of dextrorphan, the metabolite of a once-common ingredient in cough syrup, according to a copy of the ruling and racing officials.

The ruling, issued on Thursday, states that the post-race sample for Maker’s horse was now considered as “passed,” based on “new scientific findings regarding the metabolism and disposition of dextrorphan in horses.” In addition to rescinding the suspension, which Maker had appealed, the horse who tested positive, Harlan’s Howling, was restored to first place in the race from which he was disqualified, an $18,000 maiden special weight.

The stewards will also rescind a 30-day suspension for trainer Michael Ann Ewing, who was suspended in August based on a post-race positive for dextrorphan in a horse she trained who won a race at Churchill Downs on Nov. 28, 2015, according to Kentucky racing officials. The order to rescind the suspension will be based on the same criteria as the Maker ruling, the officials said.

Maker, reached by phone on Friday, said he was “satisfied” that the suspension had been rescinded, and he said that he had been told that the substance was likely found in the horse as a result of environmental contamination.

“It just shows how careful you have to be when they are testing for everything down to these little amounts,” Maker said.

Dextrorphan is the metabolite of dextromethorphan, and it can act as a cough suppressant with mildly psychoactive properties. It can also act as a stimulant or a sedative, depending on the animal. At the time of Maker’s positive – which occurred in a race at Turfway Park in January, in the middle of cold season – the substance had not been found in a post-race sample in decades, if it had been found at all.

Last September, a paper in the American Journal of Veterinary Research stated that the disposition of dextromethorphan “varies markedly in horses,” which would lead to questions regarding the levels of the drug found in a post-race test. The paper, which was co-written in part by Dr. Heather Knych, a leading equine pharmacology researcher, appeared after both suspensions were handed down.

“It was the right thing to do based on the information contained in the study,” said Marc Guilfoil, the executive director of the commission, in regards to rescinding the suspensions. “Those would not have been considered positives if we knew then what we know now.”

Maker had said that he had never administered the substance to the horse. He appealed the ruling last April after it was first issued and received a stay of the suspension as a result of the appeal. Ewing had also appealed her suspension.