Abstract

Critically evaluating the pharmacokinetic behavior of a drug in the body provides crucial information about how to effectively treat a patient. Currently, pharmacokinetic studies that exist in fish have primarily focused on drugs used to treat infectious disease and minimal attention has been given to analgesic drugs. The objective of this study was to determine the pharmacokinetics of meloxicam (1 mg/kg) in tilapia (Oreochromis niloticus). A single dose of meloxicam was administered either intravenously (IV) or intramuscularly (IM). Blood samples were obtained at predetermined times after drug injection. Plasma meloxicam concentrations were determined and noncompartmental pharmacokinetic analysis was performed. The mean terminal half-life of meloxicam after IV and IM administration was 1.36 hours and 1.8 hours, respectively. The area under the plasma concentration-versus-time curve extrapolated to infinity was 11.26 h·µg/mL after IV administration and 5.72 h·µg/mL after IM administration (1.97 ratio). The mean peak plasma concentration after IM injection was 1.95 µg/mL. Bioavailability of meloxicam after IM administration was approximately half that of IV administration. Elimination was relatively rapid in both routes of administration, suggesting that maintaining clinically relevant plasma concentrations may be difficult using this dose. Administration of meloxicam at a dose of 1 mg/kg in tilapia may be useful for short, minimally painful procedures, but further studies are needed. This study represents the first pharmacokinetic evaluation of a nonsteroidal anti-inflammatory drug in a fish species.