Pharmacokinetics of tildipirosin in horses after intravenous and intramuscular administration and its potential muscle damage.

This research investigates the effects of tildipirosin, a new antibiotic used in veterinary practice, when administered to horses. The paper specifically examines how the drug affects horses when given intravenously and intramuscularly, and the subsequent potential for muscle damage and heart toxicity.

Objective and Methodology

• The study aims to investigate how tildipirosin, used in veterinary care for respiratory infections, interacts with horses when administered both intravenously (IV) and intramuscularly (IM). There is a lack of information available regarding the effects of intramuscular administration of tildipirosin on horses, making this study crucial in expanding our understanding.
• This was a crossover study with six mature Spanish-breed horses, where the drug was given either intravenously or intramuscularly and effects observed over a 30-day period.
• Tildipirosin plasma concentrations were measured using an HPLC assay with UV detection.
• The researchers assessed muscle damage and inflammation using creatine kinase (CK) and haptoglobin (Hp) respectively. CK-MB (a specific type of CK) and troponin were used to evaluate potential heart damage.

Findings

• The study found that peak concentrations of tildipirosin were reached 0.60 hours after intramuscular administration.
• The bioavailability of the drug, or how much of it was absorbed into the body, was very high at 109.2%. The researchers also determined its steady-state volume of distribution and clearance rates.
• Importantly, the study found no evidence of heart damage as a result of tildipirosin administration. The levels of CK-MB and troponin (markers of heart damage) were not significantly different from their base levels after the treatment period.
• The study did find evidence of minor local reactions after intramuscular administration of the drug, and mild myolysis (muscle breakdown) was detected for 48 hours post-administration.

Conclusion

• The research concluded that tildipirosin could be a useful treatment for respiratory infections in horses given its distribution, high bioavailability and lack of adverse reactions.
• However, minor local reactions and muscle breakdown were noted after intramuscular administration, suggesting that this form of delivery may need to be further studied or potentially modified for improved safety in horses.