Estimation of the probability for exceeding a threshold concentration of furosemide at various intervals after intravenous administration in horses.

The research is about estimating the chances of surpassing a certain concentration of furosemide in horses after intravenous injection. It’s discovered that these chances decrease over time and increase with dosage.

Study Design and Methodology

• The investigation involved 12 mature healthy horses, a mix of Thoroughbreds and Quarter Horses.
• Venous blood was collected from each horse before and at several intervals over a period of 6 hours after the administration of furosemide (either 250 mg or 500 mg).
• Furosemide concentrations were determined through the enzyme-linked immunosorbent assay (ELISA) technique.
• The concentration of furosemide was modeled as a function of time, accommodating both inter (among different horses) and intra (within the same horse) variability.

Pharmacokinetic Modeling and Analysis Method

• A semi-parametric smooth functional averaging method was used for estimating the probability of exceeding a threshold concentration of 100 ng/ml as a function of time based on the pharmacokinetic data.
• A bootstrap approach, a resampling technique used to estimate statistics on a population by sampling a dataset with replacement, was applied to evaluate the inherent variation in this estimated probability.

Results

• The calculated probability of surpassing the threshold concentration of 100 ng of furosemide per ml, ranged from 11.6% at 4 hours to 2.2% at 5.5 hours after administering 250mg of furosemide per horse.
• The same probability was found to be ranging from 34.2% at 4 hours to 12.3% at 5.5 hours after giving an IV of 500 mg of furosemide per horse.
• The probability of a horse being falsely identified in violation of regulatory concentrations is inversely associated with the time elapsed since administration and directly associated with the dose administered.

Conclusion

• The study concluded that due to the variability in how different horses process furosemide, some horses may be incorrectly classified as exceeding the regulatory concentrations.