New Findings on the Pharmacokinetics of Cefovecin (Convenia) in Marine Mammals
The pharmacologic properties of cefovecin (Convenia® Pfizer Limited, Sandwich-Kent CT13 9NJ, UK) may pose an advantage for the exotic veterinary field1,3 due to its broad-spectrum,4 administration route, and long duration of activity, which overall allows minimal handling and stress. Preliminary studies proved that administration of cefovecin at 8 mg/kg induces plasma concentrations over the MIC90 during 17 days in adult bottlenose dolphins (Tursiops truncatus) and around 80 days in adult Patagonian sea lions (Otaria flavescens).2
In the present study, cefovecin was administered subcutaneously in sea lions at three doses (2, 4, 8 mg/kg). Peak plasma concentrations (14.31, 24.30, and 55.21 μg/ml, respectively) and total drug in plasma along treatment (312, 663, and 881 μg∙d/ml) were dose dependent. However, the maintenance of therapeutic concentrations seemed not to differ between doses of 4 and 8 mg/kg (tC>MIC90≈80 d), being significantly shorter for the 2 mg/kg dose (tC>MIC90≈50 d).
Intramuscular administration at 4 mg/kg in a walrus (Odobenus rosmarus) induced a lower peak in plasma levels (11.86 μg/ml) than those estimated for sea lions, although the kinetic behaviour and maintenance of plasma therapeutic levels (tC>MIC90>50 d) seemed to be similar for both species.
Four dolphin neonates were treated at 8 mg/kg (n=3) and 16 mg/kg (n=1). At 8 mg/kg, the maximum drug concentration observed in neonates was lower (35.49 μg/ml) to those reported for adults (79.19 μg/ml). Significant differences were also found in the duration of the drug concentrations over the MIC90 (13 vs 17 d, respectively). Double dosage of 16 mg/kg seemed only to affect the peak plasma concentration after injection (49.67 μg/ml) but not the duration of the treatment (tC>MIC90=12 d).
The authors would like to acknowledge Pfizer Salud Animal for their support, as well as all the Biology Department of the L’Oceanogràfic, Zoomarine and Oltramare for their great effort in animal training, allowing for sampling the animals routinely to obtain the antibiotic kinetic curves.
1. Bertelsen MF, Thuesen LR, Bakker J, et al. Limitations and usages of cefovecin in zoological practice. In: Proceedings from the International Conference on Diseases of Zoo and Wild Animals. 2010;140–141.
2. García-Párraga D, Gilabert JA, Valls M, et al. Pharmacokinetics of cefovecin (Convenia®) after intramuscular administration to dolphins (Tursiops truncatus) and sea lion (Otaria flavescens). In: Proceedings from the IAAAM 41st Annual Conference. 2010;42–43.
3. García-Párraga D, Ros-Rodríguez JM, Álvaro T, et al. Preliminary study of cefovecin (Convenia®) pharmacokinetics in several aquatic species. In: Proceedings from the 38th Symposium of the European Association of Aquatic Mammals. 2010.
4. Stegemann MR, Pasmore CA, Sherington J, Lindeman CJ, Papp G, Wigl DJ, Skogerboe TL. Antimicrobial activity and spectrum of cefovecin, a new extended spectrum cephalosporin, against pathogens collected from dogs and cats in Europe and North America. Antimicrob Agents Chemother. 2006;50:2286–2292.