Abstract
Pharmacological 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-spectrum4 administration route and long duration of activity that overall allows minimal handling and stress. Preliminary studies proved that administration of cefovecin at the recommended dosage in small animal clinics (8 mg/kg) induces plasma concentrations over the MIC90 during 17 d in adult bottlenose dolphins (Tursiops truncatus) and around 80 d in adult Patagonian sea lions (Otaria flavescens).2
In subsequent studies, cefovecin was administered subcutaneously in different adult sea lions at three lower dosages (4, 2 and 1 mg/kg). Peak plasma concentrations and the area under the plasma concentration time-curve 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). Results for the 1 mg/kg dose in Patagonians were still pending at the time of submitting this abstract. A California sea lion was also treated at 4 mg/kg showing a very similar kinetic performance to Patagonias, and keeping plasma concentrations over the MIC90 during 57 d. Based on this preliminary information, it seems that for most cases when treating otarids, lower dosages than the recommended ones in pet clinics should be enough to maintain a prolonged antibiotic coverage.
Intramuscular administration at 4 mg/kg in a walrus (Odobenus rosmarus) induced a lower peak in plasma levels 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. Another walrus was administered with a lower dosage of 2 mg/kg, but results of this study are still pending.
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) than 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).
Another 2.5-year-old dolphin was recently treated with 8 mg/kg IM, showing a pharmacokinetic performance between adult and neonate dolphins. Based on these findings, the recommended dosage for cefovecin in dolphins would be the same as domestic carnivores (8 mg/kg) but always considering the potential shorter life in juvenile individuals.
Acknowledgements
The authors would like to acknowledge Pfizer Salud Animal for their support as well as all of the Biology Department of the L'Oceanogràfic, Zoomarine, Mundomar and Oltremare for their great effort in animal training, allowing us to sample the animals routinely to obtain the antibiotic kinetic curves.
References
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 (ConveniaTM) 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 (ConveniaTM) 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 Chemotherap. 2006;50:2286–2292.