cefazolin
Brand: Ancef, Kefzol
Prototype Drug
Drug Class: first-generation cephalosporin
Drug Family: antibiotic
Subclass: parenteral first-generation cephalosporin
Organ Systems: infectious-disease
Mechanism of Action
Binds PBPs to inhibit bacterial cell wall transpeptidation, causing bactericidal cell lysis. Excellent gram-positive coverage; the most commonly used parenteral first-generation cephalosporin.
penicillin-binding proteins (PBPs)
Indications
- surgical prophylaxis
- skin and soft tissue infections (MSSA)
- bone and joint infections
- uncomplicated UTI
- group A streptococcal infections
Contraindications
- cephalosporin hypersensitivity
- immediate hypersensitivity to penicillin
Adverse Effects
Common
- injection site pain
- diarrhea
- elevated LFTs
Serious
- anaphylaxis
- C. difficile colitis
- neutropenia with prolonged use
Pharmacokinetics (ADME)
| Absorption | IV/IM only; IM absorption is nearly complete |
| Distribution | widely distributed; 70–86% protein bound; poor CNS penetration |
| Metabolism | not metabolized |
| Excretion | renal (unchanged >80%); dose adjustment required if CrCl <10 mL/min |
| Half-life | 1.8 hours |
| Onset | immediate (IV) |
| Peak | 1–2 hours (IM) |
| Duration | 8 hours |
| Protein Binding | 74–86% |
| Vd | moderate |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| probenecid | reduces renal tubular secretion, increases cefazolin exposure | minor |
| warfarin | gut flora suppression may enhance anticoagulation | moderate |
Nursing Considerations
- Administer IV over 10–60 minutes or IM into large muscle; monitor injection site.
- Give surgical prophylaxis dose within 30–60 minutes before incision; redose every 4 hours if surgery extends >4 hours.
- Reduce dose and extend interval when CrCl is <50 mL/min; monitor renal function.
- Assess allergy history before administration; cross-reactivity with penicillin is less than 2% for non-anaphylactic history.
Clinical Pearls
- Cefazolin is the drug of choice for surgical prophylaxis for most clean and clean-contaminated surgeries due to its narrow spectrum, safety profile, and low cost.
- Despite being an older drug, cefazolin remains a first-line agent for MSSA bacteremia, showing non-inferiority to antistaphylococcal penicillins in major trials.
Safety Profile
Pregnancy generally-safe
Lactation use-with-caution
Renal Adjustment Required
Hepatic Adjustment Not required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.