Subcutaneous cefazolin to reduce surgical site infections in a porcine model.

Background: Surgical site infections (SSIs) pose a significant health and financial burden. A key aspect of appropriate prophylaxis is the administration of antibiotics intravenously (IV). However, subcutaneous administration of antibiotics is not well described in the literature. During surgery, we hypothesize that subcutaneous injection may provide better protection against SSIs. To better understand the kinetics after subcutaneous injection, we describe the serum concentrations of cefazolin in a porcine model.

Materials And Methods: Juvenile mini-Yucatan pigs were administered 20 mL of 25 mg/kg cefazolin subcutaneously, and serial blood samples were taken for 3 h. Blood samples were analyzed for cefazolin concentration using chromatography. Pharmacokinetic data were calculated based on the blood serum concentrations.

Results: Maximum serum concentrations of cefazolin were achieved 42.6 ± 2.0 min after the time of injection and were found to be 18.8 ± 7.4 μg/mL. The elimination rate constant was 0.0033 ± 0.0016 min and the half-life was 266 ± 149 min. The area under the curve was 4940 ± 1030 μg × min/mL. The relative bioavailability of subcutaneous injection was 95% +5%/-20%.

Conclusions: Subcutaneous administration of cefazolin achieves a significantly lower maximum serum concentration than IV injection. As a result, higher doses of antibiotic can be injected locally without incurring systemic toxicity. Subcutaneous administration will therefore result in higher concentrations of antibiotic for a longer time at the incision site compared with standard IV administration. This strategy of antibiotic delivery may be more effective in preventing SSIs. Further studies are needed to detail the exact effect of subcutaneous antibiotic injection on SSI rates.