Plasma and Peritoneal Ceftriaxone Concentrations After Intraperitoneal Administration in Horses With Septic Peritonitis.
Authors: Alonso Juliana de M, Martins Evelin S, Peccinini Rosangela G, Rosa Gustavo S, Guerra Simony T, Ribeiro Márcio G, Santos Bruna, García Henry D M, Watanabe Marcos J, Takahira Regina K, Rodrigues Celso A, Alves Ana Liz G, Hussni Carlos A
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Intraperitoneal Ceftriaxone in Equine Septic Peritonitis Whilst intraperitoneal ceftriaxone administration achieves excellent peritoneal penetration in healthy horses, disease-induced changes in peritoneal physiology may alter drug distribution in clinical cases of septic peritonitis. Researchers administered daily intraperitoneal ceftriaxone (25 mg/kg bodyweight) to 26 horses with confirmed septic peritonitis and measured plasma and peritoneal concentrations using high-performance liquid chromatography at baseline, 12 and 24 hours post-administration. Peritoneal concentrations declined markedly from 5.7 μg/mL at 12 hours to 0.42 μg/mL at 24 hours—substantially lower than previously reported in healthy horses—whilst plasma concentrations fell from 1.84 μg/mL to 0.37 μg/mL over the same period. By 24 hours, concentrations fell below minimum inhibitory thresholds for both gram-negative enterobacteria (≤1 μg/mL) and gram-positive organisms (≤0.5 μg/mL), suggesting that once-daily dosing may prove inadequate for therapeutic efficacy. These findings indicate that clinicians should consider more frequent intraperitoneal administration intervals—potentially every 12 hours rather than daily—to maintain bactericidal drug concentrations in septic peritonitis cases, though further clinical outcome data would strengthen this recommendation.
Read the full abstract on PubMed
Practical Takeaways
- •When treating equine septic peritonitis with intraperitoneal ceftriaxone, consider reducing the dosing interval to every 12 hours rather than standard 24-hour dosing to maintain therapeutic drug concentrations
- •Be aware that drug concentrations in peritonitis cases are substantially lower than in healthy horses, meaning standard dosing protocols may be inadequate for infected animals
- •Monitor antibiotic efficacy closely in peritonitis cases as peritoneal concentrations drop below effective levels by 24 hours post-administration
Key Findings
- •Mean plasma ceftriaxone concentrations in septic peritonitis horses were 1.84 ± 0.43 µg/mL at 12 hours and 0.37 ± 0.07 µg/mL at 24 hours after intraperitoneal administration
- •Mean peritoneal concentrations were 5.7 ± 2.84 µg/mL at 12 hours and 0.42 ± 0.13 µg/mL at 24 hours, falling below minimal inhibitory concentrations for enterobacteria and gram-positive isolates by 24 hours
- •Ceftriaxone concentrations were significantly lower in septic peritonitis cases compared to previous studies in healthy horses, indicating different pharmacokinetics in diseased patients
- •Results suggest a 12-hour dosing interval may be more appropriate than standard dosing for horses with septic peritonitis