- 30 May
Levamisole and tetramisole are sold as wormers for farm livestock and are also sometimes marketed as “immune stimulants” or “immune modulating” substances over the internet and in tack shops. Levamisole is classified by the Association of Racing Commissioners International’s Uniform Classification Guidelines as a Class 2, Penalty Class B substance while tetramisole is not currently classified.
There is very strong evidence in the scientific literature, however, that the administration of levamisole, and potentially tetramisole, to horses results in production of aminorex and pemoline as metabolites. Aminorex and pemoline are both Penalty Class A substances, which carry a minimum one-year suspension if detected in a post-race sample. Levamisole was linked to a significant number of aminorex positive tests in 2007 and advisories were issued to horsemen to avoid levamisole administration at the time.