Therapeutic use of gentamicin in horses: concentrations in serum, urine, and synovial fluid and evaluation of renal function.

This research investigates the distribution and impact of the antibiotic, gentamicin, in horses. The study measures the concentration of the drug in various body fluids after single doses, and observes the potential impact on the kidneys.

Research Methodology

• The study involved mature and healthy horses, who were given single doses of gentamicin.
• The researchers measured the concentration of gentamicin in the serum, synovial fluid, and urine of these horses.
• Various dosage levels, including 4.4 mg and 1.7 mg per kilogram of body weight, were used to differentiate responses.
• The serum creatinine concentration was also measured, acting as an indicator of kidney function.

Findings and Observations

• The highest average concentration of gentamicin in the serum was recorded 30 minutes after administration of the higher dose. In the case of the lower dose, this peak was reached at 1 hour.
• The peak concentration of gentamicin in the synovial fluid, which lubricates the joints, was observed 2 hours post-administration for both dosage levels. The concentration was dependent on the administered dose.
• Significant quantities of gentamicin were found in both serum and synovial fluid up to 8 hours after administration.
• The rate of urinary excretion varied, with between 3.9% and 32.8% of the higher dose, and between 3.3% and 13.4% of the lower dose, being expelled through urine in the first 8 hours.

Impact on Renal Function

• The researchers monitored renal function by measuring serum creatinine concentrations in 10 horses that were given repeated doses of gentamicin.
• No significant increase in creatinine was observed, suggesting that even at higher doses of gentamicin, there was no apparent negative impact on the renal function of the horses.

Implications

• This study provides important insights into how gentamicin disperses and is metabolized in the body of horses, managing to maintain stable kidney functionality.
• However, these are observations from a single time point, and further research is needed over longer durations to understand the possible long-term effects of gentamicin use in equine treatment.