Pharmacokinetics of pergolide after intravenous administration to horses.

This research article investigates how the drug pergolide, once administered intravenously, behaves within the body of a horse. The study monitors the drug’s clearance rate, elimination half-life, and distribution volume, ultimately suggesting a twice-daily dosing schedule for more consistent pergolide concentrations.

Methodology and Samples

• In this study, eight healthy adult horses were chosen as subjects.
• The researchers administered an intravenous dose of pergolide mesylate, equivalent to 20 μg/kg (or 15.2 μg of pergolide/kg) to each horse.
• Following administration, blood samples were gathered at regular time intervals over a span of 48 hours.
• The plasma concentration of pergolide was then assessed using a high-performance liquid chromatography-tandem mass spectrometry technique.
• Pharmacokinetic parameters were ascertained using non-compartmental methods.

Summary of Results

• After the horses were given an intravenous (IV) dose of pergolide, the mean clearance, elimination half-life, and initial volume of distribution were monitored.
• The study found that the clearance rate of pergolide was 959 ± 492 mL/h/kg on average.
• The elimination half-life, the time it takes for the body to clear half of the drug, was approximately 5.64 ± 2.36 hours.
• The initial volume of distribution, a measure of how the drug spreads throughout the body, was roughly 0.79 ± 0.32 L/kg.

Conclusions and Recommendations

• Given pergolide’s elimination half-life of approximately 6 hours, it is recommended to administer the drug twice daily rather than once to reduce peak-trough fluctuations in the drug’s concentration.
• However, more extensive pharmacodynamic and pharmacokinetic studies on pergolide and its metabolites are required in order to ascertain the plasma concentrations that correlate with the drug’s clinical effectiveness.
• These further studies would contribute towards discerning the therapeutic range of pergolide for treating pituitary pars intermedia dysfunction, a common endocrine disorder in horses.