Cefonicid

The single-dose disposition kinetics of cefonicid were determined in clinically normal lactating goats (n = 6) after intravenous (IV), intramuscular (IM) and subcutaneous (SC) administration of a conventional formulation, and after subcutaneous administration of a long-acting formulation (SC-LA). Cefonicid concentrations were determined by high performance liquid chromatography with ultraviolet detection. The concentration-time data were analysed by noncompartmental pharmacokinetic methods. Steady-state volume of distribution (Vss) and clearance (Cl) of cefonicid after IV administration were 0.14 ± 0.03 L/kg and 0.51 ± 0.07 L/h·kg, respectively. Following IM, SC and SC-LA administration, cefonicid achieved maximum plasma concentrations of 14.46 ± 0.82, 11.98 ± 1.92 and 17.17 ± 2.45 mg/L at 0.26 ± 0.13, 0.42 ± 0.13 and 0.83 ± 0.20 hr, respectively. The absolute bioavailabilities after IM, SC and SC-LA routes were 75.34 ± 11.28%, 71.03 ± 19.14% and 102.84 ± 15.155%, respectively. After cefonicid analysis from milk samples, no concentrations were found above LOQ at any sampling time. From these data, cefonicid administered at 20 mg/kg each 12 hr after SC-LA could be effective to treat bacterial infections in lactating animals not affected by mastitis problems.

The in vitro activity, pharmacokinetics, adverse effects, and clinical efficacy of cefonicid are reviewed. Also discussed are formulary considerations and bacterial resistance. Cefonicid, an investigational agent near approval, is less active than other currently available first- and second-generation cephalosporins against gram-positive cocci, particularly Staphylococcus. Cefonicid and cefamandole have similar activity that is superior to the first-generation cephalosporins against Escherichia coli, Klebsiella, Citrobacter spp., Enterobacter spp., indole-negative Proteus spp., and Providencia spp. Organisms such as Serratia marcescens, Acinetobacter, Pseudomonas, and Bacteroides fragilis are resistant to cefonicid. Despite a small volume of distribution and high protein binding, cefonicid achieves high tissue concentrations. Approximately 90% of an administered dose is excreted unchanged in the urine, and the elimination half-life is approximately four hours. Cefonicid is usually well tolerated. In treating skin infections, cefonicid was usually less effective than cefazolin against Staphylococcus aureus. In genitourinary infections, cefonicid 1 g daily (as the sodium salt) in a single dose has shown comparable efficacy to cefamandole or amoxicillin given in multiple daily doses. Based on available data, single daily dosing of cefonicid in the therapy of Staph. aureus endocarditis is not effective. In studies of patients undergoing hysterectomy, cesarean section, cholecystectomy, and colorectal surgery, cefonicid 1 g given as a single preoperative dose has produced results comparable with those of cefoxitin 1-2 g (as the sodium salt) given preoperatively and for several doses postoperatively. The major clinical uses of cefonicid will probably be as a possible cost-reducing alternative (based on a single daily dose) to currently available first- and second-generation cephalosporins for the treatment of community-acquired pneumonia and infections caused by enteric organisms. It may also be useful as a possible cost-reducing alternative to cefoxitin for prophylaxis in hysterectomy and biliary tract surgery.

Cefonicid is a new second-generation cephalosporin with a broad antimicrobial spectrum of activity and a prolonged serum elimination half-life. It has good in vitro activity against methicillin-sensitive Staphylococcus aureus, nonenterococcal streptococci, Hemophilus influenzae, Neisseria gonorrhoeae, Neisseria meningitidis and many of the commonly isolated Enterobacteriaceae. Organisms usually resistant to cefonicid include species of Pseudomonas, Serratia, Acinetobacter and Providencia, and Bacteroides fragilis. The drug is 98% protein bound in human serum, which probably contributes to its significant reduction of antimicrobial activity measured in serum. Limited clinical trials have demonstrated it to be effective for surgical prophylaxis and for treating infections of the urinary tract, lower respiratory tract and bone. Failures have been reported in treatment of soft tissue infections and endocarditis caused by S. aureus. A potential cost reduction may be achieved by administering a single daily dose of cefonicid for established infections or a single preoperative dose for effective surgical prophylaxis instead of multiple-dose regimens of other, similar agents.