From the Guidelines
Prophylactic cefazolin should generally not be continued beyond 24 hours postoperatively, with very few exceptions, as extending prophylaxis beyond 24 hours does not reduce surgical site infection rates but increases the risk of adverse effects including Clostridioides difficile infection, antimicrobial resistance, and other complications 1.
Indications for Extended Prophylaxis
The primary indication for extending prophylactic cefazolin to 48 hours is in cardiac surgery, particularly following coronary artery bypass grafting or valve replacement procedures.
- For most other surgical procedures, including orthopedic, general, gynecologic, and vascular surgeries, a single preoperative dose or continuation for less than 24 hours is sufficient and recommended.
- When used for cardiac surgery, cefazolin is typically dosed at 2g IV (3g for patients >120kg) before incision, with redosing every 4 hours during the procedure and then every 8 hours postoperatively for up to 48 hours.
Rationale for Extended Duration
The rationale for the extended duration in cardiac surgery relates to the presence of indwelling devices, prolonged procedures, and the catastrophic nature of potential infections, though even this practice has been questioned in recent studies showing similar outcomes with shorter durations 1.
Potential Risks of Extended Prophylaxis
Extending prophylaxis beyond 24-48 hours can lead to several unintended side effects, including hypersensitivity reactions, renal failure, antimicrobial resistance, and Clostridium difficile-associated diarrhea 1.
Recommendations
- Prophylactic antimicrobials should be infused within 60 minutes of the incision, whereas vancomycin, aminoglycosides, and quinolones should be infused within 120 minutes.
- The dosing of these prophylactic antimicrobials should be adjusted on the basis of the patient’s weight and re-dosed at intervals of every two half-lives or when excessive blood loss occurs during the procedure.
- For surgeries defined as clean or clean–contaminated, the use of all perioperative antimicrobials should be discontinued within 24 hours after the procedure 1.
From the FDA Drug Label
In surgery where the occurrence of infection may be particularly devastating (e.g., open-heart surgery and prosthetic arthroplasty), the prophylactic administration of cefazolin for injection may be continued for 3 to 5 days following the completion of surgery.
The indication for prophylactic cefazolin to continue is for 3 to 5 days in certain surgical procedures, such as open-heart surgery and prosthetic arthroplasty, where the occurrence of infection may be particularly devastating. However, 48 hours is not explicitly mentioned as a recommended duration. Therefore, based on the available information, it is not possible to conclude that prophylactic cefazolin should be continued for 48 hours. 2 2
From the Research
Indication for Prophylactic Cefazolin
- The indication for prophylactic cefazolin to continue for 48 hours is not strongly supported by the available evidence 3, 4.
- A study published in 2018 found that a single dose of cefazolin 2g, 30 minutes before surgery, was associated with a lower rate of surgical site infections (SSIs) in orthopaedic oncological surgery, and that prolonged post-surgical prophylaxis may undermine the patient's bacterial flora and select resistant pathogens 3.
- Another study published in 2021 found that a single 2g dose of cefazolin may be adequate for prophylaxis in immunocompetent patients with normal pharmacokinetics and low bacterial burdens 4.
- There is no current evidence to suggest that continuing prophylactic cefazolin for 48 hours is more effective than a single dose or a 24-hour course in preventing SSIs 3, 4.
Dosage and Duration of Cefazolin Prophylaxis
- The optimal dosage and duration of cefazolin prophylaxis are still unclear, and more research is needed to determine the most effective regimen 4, 5, 6.
- A study published in 2019 found that a 2g dose of cefazolin was not significantly associated with a higher prevalence of SSIs in obese patients, but trends towards an increase were evident 5.
- Another study published in 2020 found that a 2g dose of cefazolin was not significantly more effective than a 1g dose in preventing SSIs in foot and ankle surgery, although the decrease in SSI rate from 6.5% to 4.8% may be clinically relevant 6.
Management of Surgical Site Infections
- The management of SSIs involves a combination of antibiotic prophylaxis, source control, and surgical debridement 7.
- Cefazolin is recommended for the treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia, while vancomycin or daptomycin are recommended for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia 7.