From the Research
For obese patients receiving cefazolin, no dose adjustment is necessary to ensure adequate surgical site infection prophylaxis, and a standard dose of 2 grams with redosing at 4 hours is sufficient. This recommendation is based on the most recent and highest quality study, which found that cefazolin dosing adaptations are not required for surgical prophylaxis in obese patients 1. The study used a model-based analysis of cefazolin pharmacokinetics and found that 2 grams of cefazolin with redosing at 4 hours was the most suitable dosing regimen for both obese and non-obese patients. Key points to consider include:
- The study used nonlinear mixed-effects modelling to analyze pharmacokinetic data from plasma and interstitial space fluid (ISF) of adipose tissue in 15 obese and 15 non-obese patients 1.
- The results showed that the probability of target attainment (PTA) and the cumulative fraction of response (CFR) for plasma and ISF were ≥90% for the 2 gram dose with redosing at 4 hours 1.
- Other studies have also found that weight-based dosing of cefazolin in obese patients is not necessary, as cefazolin does not penetrate adipose tissue regardless of IV dose 2.
- Additionally, a study found that the prevalence of surgical site infections (SSIs) in obese patients who received 2 grams of cefazolin was not significantly increased compared to non-obese patients 3.
- Another study found that there was no significant difference in SSI with a standard prophylactic dose of two grams of cefazolin between obese and non-obese patients 4. Overall, the evidence suggests that a standard dose of 2 grams of cefazolin with redosing at 4 hours is sufficient for obese patients, and dose adjustment is not necessary.