1st-gen cephalosporin
Cefazolin
Ancef No ASTM class color (white) 1 g / 2 g vials (reconstituted)
Default surgical prophylaxis: right dose, within 60 minutes of incision, redose every 4 hours.
Typical adult doses
| Indication | Dose | Onset | Duration |
|---|---|---|---|
| Surgical prophylaxis | 2 g IV (3 g if ≥ 120 kg) within 60 min before incision | — | — |
| Redose | Every 4 h, or after major blood loss | — | — |
| Alternatives | Vancomycin 15 mg/kg starting within 120 min; clindamycin 900 mg (severe β-lactam allergy) | — | — |
Mechanism
Inhibits bacterial cell-wall synthesis.
Key effects
- Covers skin flora (staph, strep)
Watch out for
- Anaphylaxis (antibiotics are a leading cause of perioperative anaphylaxis)
- Most “penicillin allergy” labels can still receive cefazolin (distinct R1 side chain) — team decides
- Vancomycin infused too fast → infusion reaction
Pimp questions
Pimp question
When must cefazolin be given, and when redosed?
Answer
Within 60 minutes before incision; redose every 4 hours (or with major blood loss).