PHARMACOKINETICS OF A SINGLE DOSE OF INTRAMUSCULAR AND ORAL MELOXICAM IN YELLOW STINGRAYS ().

Elasmobranchs are popular display animals in public aquaria and zoos, but medical management gaps remain in the understanding of the pharmacokinetics of analgesics and pain management in these species. Meloxicam is a nonsteroidal anti-inflammatory drug that has been evaluated intravenously and intramuscularly in teleosts, but has yet to be studied in any elasmobranch species. The pharmacokinetics of meloxicam were determined in 17 yellow stingrays (). All stingrays were determined to be healthy from complete physical examinations and baseline bloodwork performed prior to study inclusion. A single dose of 1 mg/kg meloxicam intramuscularly was administered to all rays, followed by a 2 mg/kg oral dose after an 8 wk washout period. Blood samples were collected from the mesopterygial vein at baseline and nine time points up to 96 h after administration of meloxicam. Plasma concentrations were determined using reversed-phase high-performance liquid chromatography. Pharmacokinetic analysis was performed using a noncompartmental technique. The mean peak plasma concentrations for intramuscular and oral meloxicam were 1.29 and 0.42 µg/ml, respectively. The mean terminal half-lives of meloxicam after intramuscular and oral administration were 5.75 and 15.46 h, respectively. Based on these findings, the recommended meloxicam dosage and frequency for yellow stingrays is 2 mg/kg orally once daily. Due to rapid elimination with the intramuscular administration, maintaining clinically relevant plasma concentrations may be difficult using this route. Further studies are needed to determine multidose pharmacokinetics of meloxicam in yellow stingrays, as well as single-dose and multidose pharmacokinetics in other elasmobranch species.