Increasing the Dosage: Pharmacokinetics of Meloxicam after Single Administration of 1.5 mg/kg PO and IM in Nursehound Sharks (Scyliorhinus stellaris)
Abstract
Meloxicam is a non-steroidal anti-inflammatory drug selectively inhibiting the cyclooxygenase (COX)-2 enzyme, with minimal effect on COX-1.6 COX-2 genetic expression has been confirmed in many fish species, and COX activity has shown in vitro evidence in elasmobranchs.1,7 Meloxicam is indicated as an analgesic and anti-inflammatory in a wide range of exotic animal species due to its good pharmacokinetic (PK) properties, tolerance, and efficacy.2 Meloxicam is frequently used in clinical management of inflammation in sharks and rays in aquariums. However, in the absence of specific PK data, dosages are generally extrapolated from other non-related exotic animal species.3,5 Our previous studies in nursehound sharks (Scyliorhinus stellaris) administered meloxicam at 0.5 mg/kg, orally (PO) and intramuscularly (IM), provided promising results for IM administration and showed important differences in absorption between enteral and parenteral routes.4 The present study evaluated variations in meloxicam PK when meloxicam dosage was increased to 1.5 mg/kg. In this study, 6 healthy adult nursehound sharks were administered meloxicam following three different administration procedures: PO voluntary ingestion with food, PO forced tube-feeding, and IM injection. A four-week washout period was allotted between studies. Meloxicam administered PO did not produce detectable plasma levels. However, PK results after IM administration showed a mean maximum plasma concentration ± SEM of 806 ± 66 ng/ml and a mean terminal half-life of 15.97 ± 1.20 h, suggesting that a dosage increase to 1.5 mg/kg could be needed to achieve therapeutic concentrations during a longer inter-dosage period in nursehound sharks.
Acknowledgements
This study could not have been developed without the help and dedicated care of the aquarist team forming part of the “Oceans” and “Quarantine” departments at Oceanogràfic of Valencia. This study was supported by Fundación Oceanogràfic and the Complutense University of Madrid.
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