Antibacterial dosage regimens are poorly established in many reptiles and especially for sea turtles. Ceftazidime is a broad spectrum antimicrobial which is particularly active against gram-negative bacteria such as Vibrio spp., Aeromonas spp. and Pseudomonas spp. often associated with morbidity and mortality of sea turtles.1-3 This study was performed to determine the pharmacokinetics of a single injection of ceftazidime in yearling loggerhead sea turtles (Caretta caretta). Eight juvenile loggerhead sea turtles weighing 1.25 (±0.18) kg were divided into two groups. Four animals received 20 mg/kg of ceftazidime (Tazidime, Eli Lilly and Co., Indianapolis, IN) intravenously and four received the same dose intramuscularly. Intravenous doses were given in the left cervical sinus. Intramuscular doses were injected into the left deltoid muscle. Repeated blood sampling was performed at times 0, 0.5, 1.5, 3, 6, 12, 24, 48, 72, 96 and 120 hours post-introduction of the drug. Blood collection sites were alternated between right and left cervical sinuses. Blood plasma ceftazidime concentrations were analyzed by reverse-phase, high-performance liquid chromatography (HPLC) using a reverse-phase C-18 column (Waters C-18 NovaPak Radial Compression Cartridge) and a 28% methanol/72% 0.01 M-acetate buffer solution as the mobile phase. Blank (untreated) sea turtle plasma was spiked with known concentrations of ceftazidime and analyzed to determine quality control values. Ceftazidime plasma concentrations were detected at all time points for all turtles and were above the MIC for Pseudomonas as long as 72 hours after the IM and IV injection.
1. Aguirre AA, Balazs GH, Zimmerman B, Spraker TR. Evaluation of Hawaiian green turtles (Chelonia mydas) for potential pathogens associated with fibropapillomas. J Wildl Dis. 1994;30:8–15.
2. Campbell TW. Sea turtle Rehabilitation. In: Mader DR, ed. Reptile Medicine and Surgery. Philadelphia, PA: WB Saunders; 1996:427–435.
3. Richards DM, Brogen RN. Ceftazidime: a review of its antibacterial activity, pharmacokinetic properties, and therapeutic use. Drugs. 1985;29:105–161.