Pharmacokinetics and pharmacodynamics of olopatadine following administration via nasogastric tube to healthy horses.

The research conducted an investigation into the pharmacokinetics (the movement of drugs in the body) and pharmacodynamics (the study of the biological effects of drugs) of the drug olopatadine in healthy horses, finding it may provide a strong and long-lasting inhibitory effect against histamine-induced wheals in horse skin.

Study Details

• The researchers used 4 healthy adult Thoroughbreds for the experiment.
• Each horse was given a dose of olopatadine (0.1 mg/kg) via a nasogastric tube – a tube inserted through the nose and into the stomach.

Methodology

• After drug administration, blood samples were taken at predetermined intervals to track the concentration of the drug in the horse’s plasma.
• The effectiveness of olopatadine as an antihistamine was tested by causing wheals (swollen, itchy areas of skin) with an injection of histamine.
• Wheal sizes before and after olopatadine administration were compared to evaluate the drug’s inhibitory effects.

Results and Findings

• The mean maximum plasma olopatadine concentration was reached approximately 1.5 hours after administration at a level of 48.8 ± 11.0 ng/mL.
• The terminal half-life of olopatadine, or the time it takes for the drug concentration in the body to halve, was found to be around 6.11 hours on average.
• The drug was most effective around 3.5 hours after administration, showing an average inhibitory effect of 88.2 ± 4.9% on histamine-induced wheals.
• The observed inhibition effect remained above 80% for around 12.5 hours following drug administration.
• No adverse clinical effects were noted within the study’s scope.

Conclusions and Future Research

• The study concluded that olopatadine may potentially have a strong and long-lasting inhibitory effect on histamine-induced wheals in horse skin.
• However, the researchers indicated that further clinical research with a larger number of horses would help confirm and further investigate these findings.