Intramuscular administration of robenacoxib in Caribbean flamingos (Phoenicopterus ruber) results in rapid absorption and a short plasma half-life.

OBJECTIVE

To determine the pharmacokinetics of robenacoxib after a single IM dose (2 mg/kg) in Caribbean flamingos (Phoenicopterus ruber).

METHODS

In the spring of 2025, following a pilot study to determine appropriate dosage, clinically healthy Caribbean flamingos under human care at a zoological institution received a single IM dose of robenacoxib (2 mg/kg) in the left pectoral muscle. Blood samples were collected under manual restraint using a sparse-sampling protocol, where each individual was sampled twice. Samples were collected from the right jugular vein at 15 and 30 minutes and 1, 2, 4, and 8 hours after drug administration. Plasma concentrations were determined using HPLC-MS. A naïve pooled approach was used for pharmacokinetic analysis.

RESULTS

12 flamingos were included in this study. A maximal plasma concentration of 3.51 µg/mL (range, 0.083 to 4.83 µg/mL) was observed at 15 minutes after robenacoxib administration. The plasma terminal half-life was 1.10 hours.

CONCLUSIONS

IM administration of robenacoxib (2 mg/kg) in Caribbean flamingos results in rapid absorption, with high plasma concentrations reached at 15 minutes, and has a short plasma terminal half-life.

CLINICAL RELEVANCE: A 2-mg/kg IM dose of robenacoxib in Caribbean flamingos results in maximum plasma concentrations above those considered therapeutic in domestic species with no adverse effects of administration.