Third Suspension This Year From Nikethamide Positive

South Florida trainer Roderick Rodolfo Rodriguez was, as of Oct. 29, suspended six months and fined $5,000 for a horse that tested positive for the Class I drug nikethamide and/or its metabolites. Nikethamide has been characterized as a "very dangerous drug" by the Racing Medication and Testing Consortium. The banned stimulant got the attention of regulators back in 2012 when it was found in a horse at Hollywood Casino at Charles Town Races, the first positive test for the drug seen since 2001. So far this year, three Thoroughbred cases related to positive tests for the drug and/or its metabolites have been adjudicated. The first positive was found June 16, 2025, in a now 7-year-old mare named City Signs, who raced for trainer Jabdiel Castillo at Thistledown. The second positive was in Rodriguez's 4-year-old gelding Winning Fortune, who was tested July 12, 2025, after winning a maiden claiming race at Gulfstream Park. The third positive was found in a 3-year-old filly named Curlene's Spirit, who was tested after winning a Feb. 20 claiming race at Laurel Park for trainer Jose Corrales. Corrales fought his anti-doping allegation in an arbitration hearing and ultimately was suspended two years starting Oct. 3 and fined $10,000. Castillo was suspended 18 months starting March 31 and fined $12,500. Nikethamide, or nicotinic acid diethylamide, was originally used as a stimulant to treat overdoses of sedatives, particularly barbiturates. It's use for this purpose has been replaced by other, more effective, and safer treatments. In racing, the drug's use was reportedly more prevalent in racing in the United States in the 1980s. Nikethamide is now no longer marketed or manufactured in the U.S. An analysis published in 2025 by the University of Kentucky's Maxwell Gluck Equine Research Center raised questions about using nikethamide's metabolite N-Ethylnicotinamide as an indicator of the drug's use. While nikethamide does rapidly metabolize to N-Ethylnicotinamide, this metabolite also has been detected as a trace impurity in Vitamin B3 nicotinamide supplements. The analysis also states that trace amounts of nikethamide are associated with the Corydalis genus of plants that may contaminate hay. The analysis cites three regulatory Quarter Horse cases in New Mexico, Colorado, and Oklahoma in 2023 involving penalties that were dismissed because the horses were shown to have been fed a vitamin/nutritional supplement. A summary of Corrales' arbitration hearing notes that the trainer denied giving nikethamide to Curlene's Spirit and claimed the positive must have come from a contaminated product. Horseracing Integrity and Welfare Unit investigators, according to the hearing summary, searched and tested all of Corrales' feeds and supplements and no presence of the banned substances were found. Read: RMTC Calls Nikethamide 'Very Dangerous Drug'