Pharmacokinetics, nephrotoxicosis, and in vitro antibacterial activity associated with single versus multiple (three times) daily gentamicin treatments in horses.

The research concluded that gentamicin, an antibiotic, can be administered safely to horses once daily at a dosage of 6.6mg/kg of body weight. This treatment regimen was found to be non-toxic to the kidneys and produced prolonged postantibiotic effects with higher concentration of the drug.

Objective and Methodology

• The study aimed to determine the pharmacokinetics, nephrotoxicosis, and in vitro antibacterial activity of single versus multiple daily dosages of gentamicin on horses.
• The scientists administered intravenous gentamicin at a dosage of 6.6mg/kg every 24 hours and 2.2mg/kg every 8 hours for 10 days on adult horses.
• The serum and tissue concentrations of gentamicin were measured, nephrotoxicosis from the dosage regimens was compared and microbiologic effects were determined against an equine clinical isolate of Pseudomonas aeruginosa.

Findings

• Treatment at the 6.6mg/kg dosage produced greater maximal serum concentrations and area under the concentration-vs-time curve. Essentially, this means that a single dosage of gentamicin remains present in the horse’s system for a longer duration and at a higher concentration than multiple smaller dosages.
• No nephrotoxicosis, toxicity in the kidneys, was observed in either dosage regimen. This suggests that neither of the dosage strategies cause kidney damage in horses.
• Postantibiotic effects were found to be prolonged with a higher concentration of gentamicin, indicating that the drug continues to have a bactericidal effect even after the drug concentration has fallen below the level that is usually considered effective.

Implication

• The research provides evidence that implies once-daily gentamicin treatment could be employed safely in adult horses without inducing nephrotoxicosis and with an effective prolonged postantibiotic effect.