Disposition of gentamicin administered intravenously to horses with sepsis.

This study looked at how the bodies of horses suffering from sepsis handled the antibiotic gentamicin when it was administered intravenously. It found that factors such as the horse’s plasma creatinine concentration affected the way the horse’s bodies processed and eliminated the drug, and that adjustments had to be made to the prescribed dosage in slightly over a third of the cases.

Methodology and Participants

• The study involved 35 adult horses that had been hospitalized for sepsis.
• These horses were given gentamicin intravenously over a ten-day period. The plasma concentrations of gentamicin were measured one, four, and six hours after the drug was administered on the first, third, fifth, and tenth days of treatment.
• The researchers also looked at a control group of 6 healthy horses that were also treated with gentamicin to compare the rate of drug elimination and clearance.

Findings and Results

• For the horses with a normal plasma creatinine concentration (a measure of kidney function), the elimination rate of gentamicin was generally constant on the first day.
• Another group of horses with an abnormally high plasma creatinine concentration had a slightly slower elimination rate of gentamicin.
• There was no significant difference between the elimination rates of the hospitalized horses and that of the healthy horses used as a control group. However, the clearance rate (how quickly the drug leaves the body) for the hospitalized horses with normal plasma creatinine concentration was significantly greater than both the healthy horses and those with high plasma creatinine concentrations.
• The clearance of gentamicin was significantly linked with plasma creatinine concentration in both healthy and hospitalized horses, implying an important role of kidney functionality in clearing the drug.

Changes in Medication Dosage

• Out of the 35 septic horses treated, 12 required an adjustment in their gentamicin dosages. Ten needed a decrease in dosage, one needed an increase, and another required a change in both dosage and interval of administration but with no net change in the total daily dose.
• A single horse (2.9%) developed signs of nephrotoxicosis (damaging effects on the kidney) on the 14th day of treatment, despite having appropriate concentrations of gentamicin on the 10th day of treatment.

Implications of Findings

• This research suggests that there is a need for careful monitoring and dosage adjustment when administering gentamicin to horses suffering from sepsis, especially those with abnormal plasma creatinine concentrations.
• The risk of nephrotoxicosis even under appropriate dosage implies further studies may be required on safe and effective gentamicin dosage in septic horses.