Determination of oral dosage and pharmacokinetic analysis of flecainide in horses.

The research investigates the oral dosage and pharmacokinetics of flecainide, an antiarrhythmic drug, in horses and its correlation with certain intervals in the equine electrocardiogram (ECG).

Methodology and Dosage

• The research involves the orally administration of flecainide to six healthy horses. The horses received a dose of either 4 or 6 mg/kg
• In addition to the drug administration, the equine electrocardiograms, namely PR, QRS, and QT intervals, were monitored. This is because these intervals may change in response to antiarrhythmic drugs

Data Collection and Analysis

• Blood samples were collected at timed intervals both before and after the flecainide administration to measure the plasma flecainide concentrations
• The maximum plasma concentration for the 4mg/kg does reached 1014+/-285 (SD) ng/m and 1301+/-400 ng/m for the 6mg/kg dose
• According to the pharmacokinetic analysis, clearance rates were 14.6+/-6.4 and 11.7+/-5.2 ml/kg/min and terminal elimination half-lives were 228+/-53 and 304+/-87 minutes respectively for each dosage

Findings

• The QRS and QT intervals increased significantly for both doses following administration, though Heart Rate (HR) and PR intervals did not change
• Plasma flecainide concentrations were significantly correlated with QRS (r=0.935, P<0.001) and QT intervals (r=0.753, P<0.001). This could mean that plasma concentrations of flecainide caused a significant change in QRS and QT intervals in the horses' ECG.
• The takeaway from this research is that plasma concentrations of flecainide for treating equine atrial fibrillation (a heart condition) can be obtained through oral administration of 4 and 6 mg/kg, and the drug was rapidly eliminated from the plasma in horses

Although the research was conducted on horses, the results can be extrapolated and provide insights for similar studies in other mammals, including humans. The dosage, administration, and pharmacokinetics of flecainide could be tested likewise to further validate or refute the findings of this study.