Plasma and pulmonary pharmacokinetics of desfuroylceftiofur acetamide after weekly administration of ceftiofur crystalline free acid to adult horses.

The research study involves an investigation into the efficiency and tolerability of ceftiofur crystalline free acid (CCFA) being administered weekly to adult horses for treatment of severe lung illnesses. The study concluded that weekly administration of CCFA for durations longer than the current protocol of 10 days, is both effective and well-tolerated in horses.

Research Objectives

• The main objective of this study is to examine the effects of weekly intramuscular (i.m.) administration of CCFA in adult horses. The research focuses on finding an applicable and effective treatment protocol when a longer regimen than the currently recommended 10-day course is required.
• An additional objective is to examine the levels of the drug metabolite, desfuroylceftiofur acetamide (DCA), in the plasma and the pulmonary epithelial lining fluid (PELF) of the horses and to keep track of the changes over time.

Research Methodology

• Seven adult horses were given an i.m. dose of CCFA (6.6 mg/kg body weight) on Day 0 and Day 4. Then every subsequent 7 days, the horses received 3 more doses.
• The researchers measured the concentrations of DCA in both plasma and PELF at various intervals to keep track of the drug’s effect.

Findings

• The research determined that the peak concentration of DCA in the plasma of the horses was significantly higher than in their PELF after a weekly i.m. administration.
• However, the terminal half-lives of DCA in both plasma and PELF were not significantly different, showing a controlled and consistent release of the drug in their systems.
• DCA concentrations remained within the therapeutic range for the entire dosing interval, indicating the effectiveness of the weekly dosing.
• From the findings, it became evident that following the initial two doses given 4 days apart, the weekly administration of CCFA was well tolerated by the horses.
• The results also revealed that weekly CCFA administration could be appropriate for treatment regimens longer than 10 days based on clinical signs and disease severity. This allows for the effective treatment of severe lung consolidation or pleuropneumonia in horses.

Conclusions

• The study concluded that weekly administration of CCFA resulted in steady and effective concentrations of DCA in both plasma and PELF. This points to the weekly dosage being a viable treatment option when a longer regimen is medically necessary.
• The research could usher in new protocols for treating severe lung illnesses in horses, especially in cases where long-term treatment is required.