Irish show jumper Darragh Kenny has been provisionally suspended by the Federation Equestre Internationale (FEI) after testing positive for a banned substance.
The international governing body indicated that the positive test related to a substance classified under Class S6 (stimulants) on the World Anti-Doping Agency (WADA) prohibited list.
Substances in this category can be found in prescription medications used in the treatment of medical conditions, such as attention deficit hyperactivity disorder, anaphylaxis, and cold and flu symptoms.
Kenny, who hails from Offaly but is currently based in Florida, has said that he is fully cooperating with the FEI and the International Testing Agency.
In a statement, the 37-year-old Olympian rider said: "I wish to address my current situation.
"After the European Championships earlier this year, I was notified by the FEI of a positive result for a medication prohibited under anti-doping regulations.
"The medication in question is part of a prescribed treatment I have been taking under medical supervision for ADHD.
"As a result, the FEI has imposed a provisional suspension while the matter is being reviewed.
"I am cooperating fully with the FEI and the International Testing Agency (ITA) to clarify the circumstances surrounding this case.
"I want to emphasise that I never intended to gain any competitive advantage. My sole aim was to responsibly address a medical condition under professional guidance.
"I am deeply grateful to my national federation, my sponsors, owners, clients, and the broader equestrian community for their support throughout this process.
"Thank you for your understanding."
Horse Sport Ireland stated that "as the case remains ongoing we will not be making any further comment at this time".