Pharmacokinetics of meloxicam in pigeons after single intravenous, oral, and intramuscular administration

This study aimed to determine the pharmacokinetics of meloxicam in pigeons. Twentyfour 7-wk-old meat pigeons (Columba livia) were randomly divided into 3 groups (PO, IM, and IV) and given a single dose of 1 mg/kg body weight of meloxicam. Plasma samples were taken at predetermined times, which were then analyzed using a validated high-performance liquid chromatography (HPLC) method and subjected to noncompartmental analysis using Phoenix software. Results indicated that meloxicam was absorbed effectively and quickly after PO and IM dosing. Peak concentrations (0.83 +/- 0.21 and 1.59 +/- 0.49 mu g/mL) were achieved at 2 and 0.26 h, respectively, with mean absorption times of 2.56 +/- 1.50 and 1.47 +/- 0.89 h. Bioavailability was high at 86.31 +/- 43.45% and 81.57 +/- 52.58%, respectively, and the area under the concentration-time curve (AUC(0-infinity)) was 5.33 > 2.68 and 5.03 +/- 3.26 h.mg/mL. After IV administration, the elimination was faster with a total body clearance (CL) of 188.75 +/- 83.23 mL/h/kg, an elimination half-life (t(1/2 lambda z)) of 1.76 +/- 0.56 h, and a volume of distribution at steady-state (VSS) of 427.50 +/- 188.43 mL/kg. Considering the lack of a precise analgesic threshold of meloxicam in pigeons and the notable differences in its analgesic threshold among various animal species, formulating a dosing regimen in pigeons presented a significant challenge. Based on the previous analgesic threshold (3.5 mu g/mL) in parrots, a higher dose (e.g., 2 mg/kg) or shorter dosing interval (e.g., every 6 h) is recommended for treating pain in pigeons. Nonetheless, further pharmacodynamic research is required to verify these recommendations.