Mavacoxib is a selective COX-2 non-steroidal anti-inflammatory drug that has been used for management of osteoarthritis and other inflammatory conditions in dogs.1,3 The main advantage of mavacoxib over other non-steroidal anti-inflammatory drugs is its longer plasma half-life, leading to a decrease in dosing frequency.2,3 This study determined the pharmacokinetics of mavacoxib (Trocoxil® 75 mg, Pfizer Italia s.r.l., Ascoli Piceno, Italy) in Caribbean flamingos (Phoenicopterus ruber ruber) after a single oral dose of 6 mg/kg (n=6). Blood collection was performed prior to mavacoxib administration and then at 4, 8, 24, 48, 72, 120, 168, and 336 h after administration. Plasma mavacoxib concentrations were determined using liquid chromatography with mass spectrometry, and pharmacokinetic analysis was performed using noncompartmental methods. Mean peak plasma concentration (Cmax) was (mean; range) 2.97 (2.19–4.06) µg/ml; mean time to peak plasma concentration (Tmax) was 18.68 (4.00–48.0) h; mean area under the curve (AUC) was 455 (292–637) h⋅µg/ml; and mean terminal half-life (T1/2) was 74.47 (49.57–161.4) h. Based on the results of this study, mavacoxib dosed at 6 mg/kg orally in Caribbean flamingos reaches plasma concentrations above the therapeutic concentration established for dogs, but further studies are needed to determine appropriate dosing recommendations in flamingos.
The authors thank the Department of Clinical Sciences at Kansas State University College of Veterinary Medicine for providing funding support for this study. The authors also thank the staff at the Sunset Zoo and Christine Hackworth, Christina Vincent, Cassandra Rodenbaugh, Arkady Lake, Brooke Warren, Nichole Arbona, Tori Matta, Karissa Severud, and Sarah Wilson for their assistance with various aspects of the study.
1. Cox SR, Lesman SP, Boucher JF, Krautmann MJ, Hummel BD, Savides M, Marsh S, Fielder A, Stegemann MR. The pharmacokinetics of mavacoxib, a long-acting COX-2 inhibitor, in young adult laboratory dogs. J Vet Pharmacol Ther. 2010;33:461–470.
2. Dhondt L, Devreese M, Croubels S, De Baere S, Haesendonck R, Goessens T, Gehring R, De Backer P, Antonissen G. Comparative population pharmacokinetics and absolute oral bioavailability of COX-2 selective inhibitors celecoxib, mavacoxib and meloxicam in cockatiels (Nymphicus hollandicus). Sci Rep. 2017;7:12043.
3. Lees P, Alexander-Bowman S, Hummel B, Kubiak T, Michels G, Krautmann M, Cox S, Toutain P, Stegemann M. Pharmacokinetics and pharmacodynamics of mavacoxib in the dog. J Vet Pharmacol Ther. 2009;32:105–106.