Plasma and Peritoneal Ceftriaxone Concentrations After Intraperitoneal Administration in Horses With Septic Peritonitis.

This study investigates the concentration levels of the antibiotic ceftriaxone in the blood and in the abdominal cavity of horses suffering from septic peritonitis, after the drug is administered into the abdominal cavity. The findings suggest that for effective treatment, the frequency of administration should be every 12 hours.

About the study

• In this study, the researchers’ main objective was to study the concentrations of ceftriaxone in the blood and peritoneal (abdominal) cavity of horses suffering from septic peritonitis following intraperitoneal administration. This refers to the delivery of medication directly into the stomach lining.
• This research included 26 horses that showed clinical, laboratory, and sonographic signs of septic peritonitis. All horses in the study were given ceftriaxone each day at a dose of 25 mg per kilogram of body weight, either in combination with other antibiotics or support treatments or on its own.

Method of analysis

• The researchers used high-performance liquid chromatography, a technique used to separate, identify, and quantify each component in a mixture, to measure the plasma and peritoneal ceftriaxone concentrations at different points in time: before administration, and after 12 and 24 hours of administration.

Results and comparison

• The average plasma concentrations of ceftriaxone 12 and 24 hours after administration were, respectively, 1.84 ± 0.43 and 0.37 ± 0.07 μg/mL, while the average peritoneal concentrations were 5.7 ± 2.84 and 0.42 ± 0.13 μg/mL.
• These concentration levels were found to be lower when compared to previous studies done on healthy horses, showing results under the minimal inhibitory concentration for enterobacteria (≤1 μg/mL) and for gram-positive isolates (≤0.5 μg/mL) at the 24-hour mark.

Recommendations for treatment

• Based on these observed concentrations and how drastically they dropped at the 24-hour mark, the researchers concluded that pharmacokinetics and pharmacodynamics are different in sick versus healthy horses.
• This led to a recommendation from the study authors that in the event of treating horses with septic peritonitis using ceftriaxone, the dosage should be administered every 12 hours for maximum efficacy.