Pharmacokinetics of a continuous rate infusion of ceftiofur sodium in normal foals

[Extract] Systemic bacterial infection, resulting in bacterial sepsis and systemic inflammatory response syndrome, is the primary cause of equine neonatal morbidity and mortality (Cohen, 1994; Hollis et al., 2008). Ceftiofur sodium (CS), a third-generation cephalosporin antimicrobial, has in vitro efficacy against many bacterial organisms cultured from septicemic equine neonates (Jaglan et al., 1994; Marsh & Palmer, 2001; Sanchez et al., 2008; Meyer et al., 2009). Ceftiofur sodium is a time-dependent, bactericidal, β-lactam antimicrobial (Owens & Ambrose, 2007). To optimize the likelihood of efficacy, dosing regimens are designed to maximize the duration concentrations of antimicrobial at the site of infection are greater than the MIC of the pathogen (Turnidge, 1998). For gram-positive organisms, CS has a period of post-antibiotic effect and post-antibiotic leukocyte enhancement. For gram-negative organisms no post-antibiotic effect exists and reduced efficacy of cephalosporin antimicrobial therapy has been reported when T > MIC is <80% (Craig, 2002). In neutropenic patients, maintaining T > MIC for 90–100% of the dosing interval is recommended (Turnidge, 1998).