Cocktail drug usage and etofenamate detection in post-race equine urine sample: A case report.

A recent trend in the use of high-resolution accurate mass screening (HRAMS) for doping control testing in both human and animal sports has emerged owing to significant improvement in high-resolution mass spectrometry in terms of sensitivity, mass accuracy, mass resolution and mass stability. Several HRAMS methods have been reported for the detection of multidrug residues in human or equine urine. These improved analytical technologies have led to changes in the use of prohibited substances, and the administration of more than one substance at low concentrations as a "cocktail" has become one of the methods used to alter performance in racehorses. In one of horse urine samples transferred to the analytical laboratory in Turkey for analysis, 5-hydroxymethyl meloxicam (2.96 ng/ml), etofenamate (2.15 ng/ml), flufenamic acid (108.92 ng/ml) and cobalt (200 ng/ml) were detected. These findings reveal that more than one prohibited substance was used together as a cocktail to alter the racing performance at low doses. In this case report, flufenamic acid was detected as a metabolite of etofenamate along with the parent drug. This case study also supports the advantages of metabolite analysis for anti-doping laboratories.