Larson Molly A, Credille Brent C, Berghaus Londa J, Papich Mark G, Beasley Erin M
Department of Large Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA.
Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA.
Am J Vet Res. 2025 Jan 22;86(4). doi: 10.2460/ajvr.24.08.0229. Print 2025 Apr 1.
To investigate the disposition of enrofloxacin and its active metabolite, ciprofloxacin, in plasma, pulmonary epithelial lining fluid (PELF), peritoneal fluid, and CSF in horses following IV administration of enrofloxacin at doses of 5 mg/kg and 7.5 mg/kg of body weight.
6 healthy, mature mares were randomly assigned to receive a single dose of enrofloxacin at either 5 mg/kg or 7.5 mg/kg in a crossover design with a washout period of 10 days. Concentrations of enrofloxacin and ciprofloxacin were determined in plasma, PELF, peritoneal fluid, and CSF.
Both doses of enrofloxacin were generally well tolerated. One horse developed focal, self-limiting limb edema. The median maximum concentration extrapolated to time 0 and area under the plasma concentration-versus-time curve from time 0 to the last quantifiable time point (24 hours) for enrofloxacin in plasma were significantly greater when horses were given enrofloxacin at 7.5 mg/kg. Similarly, the median elimination rate constant, half-life of the terminal phase, peak serum concentration (Cmax), area under the plasma concentration-versus-time curve from time 0 to the last quantifiable time point (24 hours), area under the plasma concentration-versus-time curve extrapolated to infinity, and mean residence time for ciprofloxacin in plasma were significantly greater following administration of enrofloxacin at 7.5 mg/kg. There were no significant differences between doses in any of the measured pharmacokinetic variables in PELF.
There was no apparent pharmacokinetic advantage of enrofloxacin at the 7.5-mg/kg dose for susceptible isolates; however, this dose achieved higher concentrations and prolonged persistence in fluid matrices. Further studies are required to evaluate repeated administration at this dose for tolerability and clinical efficacy.
Despite the wide use of enrofloxacin in horses, pharmacokinetic data is limited. This study provides pharmacokinetic data that can be used in a clinical setting.
研究静脉注射5mg/kg和7.5mg/kg体重剂量恩诺沙星后，恩诺沙星及其活性代谢产物环丙沙星在马血浆、肺上皮衬液（PELF）、腹腔液和脑脊液中的分布情况。
6匹健康成年母马采用交叉设计，随机分为接受5mg/kg或7.5mg/kg单剂量恩诺沙星组，洗脱期为10天。测定血浆、PELF、腹腔液和脑脊液中恩诺沙星和环丙沙星的浓度。
两种剂量的恩诺沙星总体耐受性良好。一匹马出现局部自限性肢体水肿。当马接受7.5mg/kg恩诺沙星时，血浆中恩诺沙星外推至时间0的中位最大浓度以及从时间0至最后可定量时间点（24小时）的血浆浓度-时间曲线下面积显著更高。同样，接受7.5mg/kg恩诺沙星给药后，环丙沙星在血浆中的中位消除速率常数、终末相半衰期、血清峰浓度（Cmax）、从时间0至最后可定量时间点（24小时）的血浆浓度-时间曲线下面积、外推至无穷大的血浆浓度-时间曲线下面积以及平均驻留时间均显著更高。在PELF中，各测量的药代动力学变量在不同剂量之间无显著差异。
对于敏感菌株，7.5mg/kg剂量的恩诺沙星没有明显的药代动力学优势；然而，该剂量在体液基质中达到了更高的浓度并延长了持续时间。需要进一步研究评估该剂量重复给药的耐受性和临床疗效。
尽管恩诺沙星在马中广泛使用，但其药代动力学数据有限。本研究提供了可用于临床的药代动力学数据。
