Cefazolin Dosing for Post-Surgical Prophylaxis
For post-surgical prophylaxis, cefazolin should be administered as a 2g IV slow infusion initially, with redosing of 1g if the procedure exceeds 4 hours, limited to the operative period (maximum 24 hours). 1
Standard Dosing Recommendations by Surgery Type
General Surgical Procedures
- Initial dose: 2g IV slow infusion 30-60 minutes before surgical incision
- Redosing: 1g if procedure duration exceeds 4 hours
- Duration: Limited to the operative period (maximum 24 hours)
Cardiac Surgery
- Initial dose: 2g IV + 1g in priming
- Redosing: 1g at the 4th hour intraoperatively 2
Orthopedic Surgery (Joint Prosthesis/Implants)
- Initial dose: 2g IV slow infusion
- Redosing: 1g if duration exceeds 4 hours
- Duration: Limited to operative period (maximum 24 hours) 2
Vascular Surgery
- Initial dose: 2g IV slow infusion
- Redosing: 1g if time exceeds 4 hours
- Duration: Single dose (unless specified otherwise) 2
Spine Surgery with Implants
- Initial dose: 2g IV slow infusion
- Redosing: 1g if duration exceeds 4 hours
- Duration: Single dose 2
Special Considerations
Timing of Administration
- Administer 30-60 minutes before surgical incision to ensure adequate tissue levels at the time of incision 1
- For lengthy procedures (>4 hours), redosing is critical to maintain therapeutic levels 3
Weight-Based Considerations
- For patients weighing ≥120 kg, some evidence suggests considering a 3g dose, though clinical evidence shows 2g may be sufficient in many cases 4
- For patients with morbid obesity (BMI 40-50 kg/m²), a 2g dose provides sufficient coverage for procedures lasting up to 5 hours 5
- For super-morbid obesity (BMI >50 kg/m²), a 3g dose may provide longer protection (up to 6.8 hours) 5
Alternative Administration Methods
- While standard practice is intermittent dosing, continuous infusion after an initial bolus has shown pharmacokinetic advantages including more stable serum levels and better tissue penetration 6
Renal Adjustment
- For patients with creatinine clearance 35-54 mL/min: Give full dose but extend interval to at least 8 hours
- For patients with creatinine clearance 11-34 mL/min: Give half the usual dose every 12 hours
- For patients with creatinine clearance ≤10 mL/min: Give half the usual dose every 18-24 hours 3
Common Pitfalls to Avoid
Extending prophylaxis unnecessarily: Single-dose or 24-hour prophylaxis is as effective as extended regimens for most procedures, with reduced costs and lower risk of antimicrobial resistance 7
Inadequate redosing during lengthy procedures: Failure to redose after 4 hours can lead to subtherapeutic levels and increased infection risk 1
Improper timing of preoperative dose: Administration should occur 30-60 minutes before incision to ensure adequate tissue levels at the time of surgical incision 1
Overlooking special populations: Patients with obesity or renal impairment require dosage adjustments to maintain therapeutic levels 3, 5
Inadequate dosing for cardiac surgery with cardiopulmonary bypass: Special dosing regimens including additional doses in the bypass circuit are recommended 8