Lidocaine, which The New York Times reports is the substance for which Arkansas Derby (G1) winner Charlatan tested positive, is most commonly used as a local anaesthetic and has legitimate medical purpose, a leading racing regulator says.
News broke Tuesday that two post-race samples from Arkansas Derby day had not yet cleared, but still needed to be verified via a split sample at a referee lab. The Times' Joe Drape reported that in addition to Charlatan, his undefeated stablemate Gamine, a $1.8 million filly who won an allowance race on the Oaklawn Park undercard, had a test flagged for lidocaine.
A ruling cannot be issued, Arkansas state steward Bernie Hettel said, until after the split sample is tested. Trainer Bob Baffert released a statement saying he's "extremely disappointed" that news leaked before a confidential second test occurred and hopes for an "expedited investigation."
Dr. Mary Scollay, executive director of the Lexington, Ky.-based Racing Medication and Testing Consortium, said Wednesday that use of lidocaine in horses often involves administering to an area before suturing a wound.
"You can use it for diagnostic nerve blocks in an effort to localize a lameness to facilitate a diagnosis,” Scollay said. “It also has use as an antiarrhythmic, during anesthesia for the most part. My assessment would be the most common use in a racehorse is for localized or regional analgesia.”
In a document distributed by the American Association of Equine Practitioners, Dr. Brett Woodie of Lexington’s Rood & Riddle Equine Hospital wrote that lidocaine is commonly used “because of its potency, rapid onset of action, moderate duration of action, topical anesthetic properties and cost.”
Further, he wrote, the medication’s “duration of action has been reported to be 1.5 to 3 hours, but clinical experience would suggest that the duration of action is shorter.”
Scollay said lidocaine “is a legitimate medication that has a role in equine practice. And quite frankly, it would be not appropriate for us to make it a banned substance at all times because that could have a negative impact on equine welfare. I wouldn’t want to have a wound sutured without lidocaine.
"We want people to be able to use it appropriately, but we also want to make sure that it does not have an impact on a horse participating in a race," she continued. "That’s why we have withdrawal guidance for its use, we have a regulatory threshold that corresponds to the withdrawal guidance.”
It remains unclear why the two Baffert trainees might have needed lidocaine, nor have the amounts found in the first test been revealed. Baffert said in his statement that, "I...look forward to being able to speak soon about any written decision of the stewards, if and when it becomes necessary and I’m allowed to under the (Arkansas Racing) Commission’s confidentiality rules."
According to the Kentucky Horse Racing Commission, up to 200 mg of lidocaine may be administered up to 72 hours before the scheduled post time of a race.
