Horseracing
The drugs most commonly detected in horseracing in Europe (France, Germany, Great Britain, Ireland and Italy) over the period 1993 to 1997 were assessed by Smith (2001). The majority of the reported findings (77%) were for substances registered for equine veterinary use. The NSAIDs (including phenylbutazone, flunixin, furosemide and naproxen) accounted for 28% of the reported findings and isoxsuprine for 22%. Isoxsuprine, a vasodilator, is widely used in veterinary practice for the treatment of navicular disease and can be detected in urine for long periods of time after dosing has ceased. Also, as a powder for oral administration through admixture with feed, it can produce serious contamination problems in the stable environment. Procaine and lidocaine accounted for 14% of reported findings and caffeine almost 9%.
For the drugs without market authorisation, anabolic steroids (including testosterone, nandrolone and boldenone) accounted for 36% of the reported findings, xanthines 26% and central nervous system (CNS) stimulant active drugs 12%. It is interesting to compare these findings with those for reported findings in the USA and Canada over a similar period. If a prohibited substance is reported in a post-race sample from a horse, the IABRW recommends the horse be disqualified. However, as with the Prohibited Substance list, some countries adopt a different policy. In an attempt to harmonise sanctions, the ARCI in North America produced Uniform Classification Guidelines for Foreign Substances and Recommended Penalties and Model Rules (ARCI 2007b). Drugs are placed in Classes 1 to 5, with Class 1 agents having a high potential to affect the performance of the horse. Class 1 agents have no place in racing and include opiates, CNS stimulants and psychoactive drugs. Class 2 agents include psychotropics, certain stimulants, depressants, neuromuscular blocking agents and local anaesthetics that could be injected as nerve-blocking agents. These drugs also have the potential to affect racing performance, but it is less than that of Class 1 agents. Class 3 agents include some drugs registered for equine veterinary use and have less potential to affect performance than Class 2 agents. Class 4 includes agents with a recognised therapeutic use and which have less potential to affect performance than Class 3 agents. Examples of drugs from Class 4 include betamethasone, dextromethorphan, diclofenac, flunixin, ibuprofen, phenylbutazone and others. Suspensions from racing and fines are specified for a positive finding for the various drug classes, with Class 1 agents incurring the longest suspensions and highest fines. Also prohibited under the ARCI guidelines is the possession or use of erythropoietin, darbepoietin, oxyglobin and the blood substitute Hemopure. Carter et al. (2001) reported findings for thoroughbred, standardbred and quarter horses (horses bred for maximum speed over a quarter of a mile) over the period 1995 to 1999 for racing in California, Canada, Florida, Kentucky, Mary land, New York and Ohio. Findings for Class 1 agents, for example, included morphine (15), cocaine, presumably as the major metabolite benzoylecgonine (15), strychnine (3), oxymorphone (2), apomorphine (1), dextromoramide (1) and oxycodone (1). The estimated number of samples tested per annum in Canada and six states within the USA between 1995 and 1999 was 200 000 (Carter et al. 2001). For Class 1, 2 and 3 agents, within a four-year period, 39 substances were detected a total of 389 times in an estimated 800 000 samples (incidence of reported findings of 0.049%). For comparison, within Europe, 49 substances were detected a total of 431 times in a four-year period with a total of 97 451 samples – incidence of reported findings 0.44%. The significant difference in the incidence of reported findings in the two geographical areas can almost certainly be explained by the absence of data for Class 4 and 5 agents in the American study. Many of the substances reported in Europe would fall into these classes within the USA. For example, European racing authorities place significant importance on the detection of anabolic steroids, whereas these are Class 4 agents in the USA and limited testing is applied. Also, NSAIDs and isoxsuprine are Class 4 agents and the level of phenylbutazone and/or oxyphenylbutazone in the reported samples in Europe would be well below the USA threshold (5000 lg/L). The difference in the incidence of reported findings reflects, in part, the difference in philosophical approaches to doping control currently adopted on the two continents: zero tolerance versus permitted medication. It is interesting to note the influence that the introduction of new or more sensitive tests can have upon reporting statistics. Carter et al. (2001) reported 24 findings of Class 1 agents in standardbred racing in the USA over the period 1995 to 1999; 23 of the findings were for the drug metaraminol. These findings were all reported in one state, Louisiana, occurred over a short period of time, and resulted from the intro duction of a new test. A similar situation arose with the drug clenbuterol when a more sensitive test was introduced in 1998.
