Pharmacokinetics, pharmacodynamics, and metabolism of acepromazine following intravenous, oral, and sublingual administration to exercised Thoroughbred horses.

The research paper is a scientific examination of how acepromazine, a commonly used horse tranquilizer, is absorbed, metabolized, and excreted in the body of Thoroughbred horses when administered intravenously, orally, and sublingually.

Methodology

• The study was conducted on fifteen adult Thoroughbred horses, all of which had engaged in physical exercise leading up to the research process.
• Each of these horses was administered a single dose of 0.09 mg/kg of acepromazine via intravenous, oral, and sublingual methods.
• Blood and urine samples were then collected from these horses at the commencement of the experiment and repeatedly over the course of 72 hours.
• These samples were analyzed using a technique known as liquid chromatography-tandem mass spectrometry to ascertain concentrations of the parent drug and its two primary metabolites in the bloodstream and urine.
• In-vitro testing was also conducted where acepromazine was combined with whole equine blood to see how it might additionally be metabolized by red-blood cells.

Results

• From the analysis of the blood and urine samples, it was discovered that acepromazine could be detected for about 24 hours after intravenous administration, and 72 hours after both oral and sublingual administration.
• The half-life of the drug, that is, the time taken for the concentration of the drug in the body to reduce to half its initial levels, was found to be around 5.16 hours, 8.58 hours, and 6.70 hours following intravenous, oral, and sublingual administration respectively.
• The study further revealed that the effects of the tranquilizer were visible within 5 minutes after intravenous administration, and within 15 minutes after both oral and sublingual administration, with the sedation lasting for a period of two hours.
• Notably, there were no observable adverse effects from the administration of the drug, with only minimal changes in the horses’ heart rates.

Conclusions

• The outcomes of this study provide valuable insight into how acepromazine works within the bodies of Thoroughbred horses following different modes of administration.
• These results could be instrumental in making sound veterinary decisions on the choice of administration and dosage of acepromazine as a tranquilizer for horses