Effects of fenoldopam mesylate on systemic hemodynamics and indices of renal function in normotensive neonatal foals.

This research paper examines and compares the effects of both low and high dosage fenoldopam mesylate, a dopamine-1 receptor agonist, on systemic circulation, urine output, and creatinine clearance of healthy newborn foals. The study found that while high dosage fenoldopam altered heart rate and blood pressure with no significant impact on renal function, low dosage fenoldopam increased urine output without affecting systemic hemodynamics.

Research Goal

• The main objective of this study was to analyze how two different dosages of fenoldopam, a dopamine receptor agonist, would affect the systemic circulation, urine output, and the clearance of creatinine in healthy neonatal foals.

Methodology

• The study involved six Thoroughbred foals which were given two doses of fenoldopam (a lower dose of 0.04 microg/kg/min and a higher dose of 0.4 microg/kg/min) and a saline control, in a controlled, blind test.

Results

• The research found that high-dosage fenoldopam had no noticeable effect on the renal function of the foals. However, it caused a significant increase in heart rate and a decrease in the mean, systolic, and diastolic arterial blood pressure compared to the control.
• On the other hand, low-dosage fenoldopam had no significant effects on the systemic circulation of the foals but resulted in a notable increase in urine output. There were no significant effects on creatinine clearance or the fractional excretions of sodium, potassium, or chloride compared with the control.

Conclusions

• The researchers concluded that high-dosage fenoldopam had effects on the cardiovascular system – increasing heart rate and decreasing arterial blood pressure – but had no significant impacts on renal functionality.
• In contrast, low-dosage fenoldopam increased urine output without affecting the systemic circulation. The cause of this difference, which appears to be unique to neonatal foals, merits further investigation.