Pharmacokinetics of meloxicam for medication control in racing greyhounds

Recent published disciplinary findings from regulators of greyhound racing in Australia, Great Britain and Ireland have shown overall that the most common non-steroidal anti-inflammatory drug (NSAID) adverse analytical finding is for meloxicam. Whilst animals used in sport should be treated as required to ensure animal welfare at the same time any such use of medication should also be controlled to ensure integrity. A pharmacokinetic study on six greyhounds was performed to measure plasma and urine levels of meloxicam to inform medication control advice. Using the standard methodology for medication control the Irrelevant Plasma Concentration was determined as 5 ng/ mL and the Irrelevant Urine Concentration was determined as 0.1 ng/mL for meloxicam. These Irrelevant Plasma and Urine Concentrations allow laboratory Screening Limits, Detection Times and Withdrawal Time advice to be determined and publicised by regulators of greyhound racing. There was identification of meloxicam in plasma prior to its administration in the study, with a potential linkage of this identification to the feeding of ‘knackery’ meat including from racehorses, and also a finding of an extended terminal phase with a terminal half life of 28 hours, and with this finding the computation that accumulation of meloxicam would occur if such meat containing meloxicam residues was eaten once per day by dogs for a few weeks. Taken together this work supports regulators advising against the feeding of such meat and that this NSAID should not be used in racing greyhounds without a considerably extended Withdrawal Time.