Clinical beta

FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.

Drug Monograph

Cefazolin

Cefazolin

First-generation cephalosporin

MSSASurgical prophylaxisStreptococcal infectionBone/joint infectionIV-only

Indication

Surgical prophylaxis • MSSA bacteremia • MSSA bone/joint infection • MSSA skin/soft tissue infection

At a glance

INDICATIONS (CORE USE)

Surgical prophylaxis • MSSA bacteremia • MSSA bone/joint infection • MSSA skin/soft tissue infection

ADULT DOSE (STANDARD)

Mild–moderate infections: 1 g IV q8h Severe infections (e.g., bacteremia): 2 g IV q8h

MAX DOSE

Common: 8 g/day — selected ICU guidance: up to 12 g/day (renal adjustment mandatory)

Route

IV, IM (IV preferred)

PEDIATRIC DOSE

25–50 mg/kg/dose IV q8h — Severe: 50 mg/kg/dose IV q8h — Surgical prophylaxis: 30 mg/kg IV once pre-incision

Do not miss

Must-not-miss safety points

Major warning

- Hypersensitivity (anaphylaxis risk); cross-reactivity possible with severe penicillin allergy - Not for MRSA or ESBL/high-risk resistant gram-negatives — treatment failure risk - Inoculum effect — risk of failure in high-burden MSSA infections (e.g., endocarditis, deep abscess) - Mandatory renal dose/interval adjustment — high dose without adjustment → encephalopathy/seizures - Surgical prophylaxis must be within 60 min pre-incision; re-dose intra-op if prolonged surgery or blood loss ≥1500 mL - No oral formulation — IV/IM only

Indications

USE IF: First-line for MSSA bacteremia (preferred over broader agents where appropriate); surgical prophylaxis; MSSA bone/joint infection; MSSA skin/soft tissue infection; susceptible streptococcal infection when first-generation cephalosporin spectrum is appropriate. AVOID IF: Not active against MRSA — do not use if MRSA suspected or confirmed; ESBL organisms — ineffective, avoid use; other high-risk resistant gram-negatives; severe cephalosporin allergy. IV-first-generation cephalosporin—excellent peri-operative and MSSA-directed option when local resistance patterns and allergy history support use.

  • Primary: Surgical prophylaxis; MSSA cellulitis; MSSA abscess with systemic features; MSSA osteomyelitis; MSSA septic arthritis; MSSA bacteremia; MSSA endocarditis
  • Secondary: Complicated UTI due to susceptible organisms; selected intra-abdominal/peritonitis combination regimens; obstetric/gynecologic peri-operative prophylaxis
  • Other: Continuous/extended infusion for deep MSSA infection; intracameral/subconjunctival ophthalmic prophylaxis (dedicated preparation)

Dosing

ADULT DOSE

Adult IV (treatment): Mild–moderate infections: 1 g IV q8h Severe infections (e.g., bacteremia): 2 g IV q8h Critically ill / augmented clearance: up to 2 g IV q6h (selected protocols) IM: possible for mild infection when appropriate (often painful; IV preferred) Surgical prophylaxis: 2 g IV once pre-incision Obesity ≥120 kg: 3 g IV once pre-incision Adult PO: not applicable

PEDIATRIC DOSE

25–50 mg/kg/dose IV q8h. Severe infection: 50 mg/kg/dose IV q8h. Surgical prophylaxis: 30 mg/kg IV once pre-incision (per pediatric reference).

  • 25–50 mg/kg/dose IV q8h
  • Severe: 50 mg/kg/dose IV q8h
  • Prophylaxis: 30 mg/kg IV pre-incision

MAX DOSE

Common max: 8 g/day — selected ICU protocols: up to 12 g/day — always adjust for renal function.

Practical Note

- Renal (give loading dose first where appropriate): • CrCl 35–54 → extend dosing interval ≥8 h • CrCl 11–34 → 0.5–1 g q12h • CrCl ≤10 → 0.5–1 g q24h - Hemodialysis: dose after dialysis (e.g., 0.5–1 g after each session per local protocol) - CRRT: higher or more frequent dosing often required — follow ICU/renal pharmacy protocol - Hepatic: no adjustment - Deep MSSA / endocarditis — use full serious-infection doses; do not underdose - Prophylaxis: within 60 min pre-incision; re-dose if surgery >3–4 h or blood loss ≥1500 mL

Warnings

Clinical warnings

  • Anaphylaxis
  • Severe cutaneous reactions (AGEP, SJS/TEN, DRESS)
  • Neurotoxicity / encephalopathy / seizures with renal impairment
  • Cross-reactivity in severe penicillin allergy
  • Additive nephrotoxicity with other nephrotoxins
  • Prophylaxis failure if mistimed or not redosed
  • Treatment failure if used for MRSA/ESBL settings

Adverse effects

  • Infusion-site phlebitis / pain (IM injection painful)
  • Nausea, diarrhea
  • Clostridioides difficile infection risk
  • Hypersensitivity including anaphylaxis
  • Severe cutaneous reactions (AGEP, SJS/TEN, DRESS)
  • Neurotoxicity / encephalopathy / seizures (often with renal impairment and high exposure)
  • Additive nephrotoxicity with other nephrotoxins

Contraindications / caution

  • Do not use: Severe cefazolin or cephalosporin hypersensitivity when cephalosporin therapy is contraindicated
  • Use caution: Immediate severe β-lactam allergy history
  • Use caution: Renal impairment
  • Use caution: Dialysis
  • Use caution: Elderly
  • Use caution: Prior seizures
  • Use caution: Multiple drug allergies
  • Use caution: Severe cutaneous drug reaction history

Drug interactions

  • Aminoglycosides → additive nephrotoxicity → monitor renal function
  • Loop diuretics → additive nephrotoxicity → monitor
  • IV contrast → additive AKI risk
  • Warfarin / VKAs → INR may rise → monitor
  • Probenecid → ↑ cefazolin levels → monitor/adjust if needed

Special populations

Pediatrics

25–50 mg/kg/dose IV q8h — Severe: 50 mg/kg/dose IV q8h — Surgical prophylaxis: 30 mg/kg IV once pre-incision

Pregnancy

Generally safe in pregnancy when indicated; widely used for peri-operative prophylaxis in obstetrics per protocol. Breastfeeding usually compatible — observe infant for diarrhea, rash, or candidiasis. Pregnancy: Generally safe; common peri-operative prophylaxis option in obstetrics.

Lactation

Compatible — monitor infant for diarrhea, rash, candidiasis.

Renal impairment

Mandatory dose/interval adjustment; high-dose regimens unsafe without adjustment — monitor for neurotoxicity.

Hepatic impairment

No specific dose change; monitor if severe liver disease or prolonged therapy.

Elderly

Dose by CrCl; higher neurotoxicity risk with accumulation.

Administration

Prophylaxis: within 60 min before incision. Re-dose intraoperatively if surgery >3–4 h or blood loss ≥1500 mL. IV preferred; IM possible but painful. Typical infusion: 1–2 g in 50–100 mL NS or D5W over ~30 min. Extended/continuous infusion may be used for deep MSSA infection per local protocol. Intracameral/subconjunctival use requires dedicated ophthalmic preparation.

Monitoring

  • Labs: renal function at baseline and during therapy; CBC and LFTs with prolonged therapy; INR if on warfarin/VKA
  • Clinical: confusion, myoclonus, seizures; rash/urticaria/bronchospasm/hypotension; infection response; prophylaxis timing and intra-op redosing
  • No clinical improvement at 48–72h → reassess diagnosis, resistance, source control, and drug interactions (DO NOT continue blindly)
  • If targets not met after reassessment of dose, organ function, and interactions → escalate per protocol (DO NOT continue blindly)

Overdose / toxicity

Clinical Picture

No fixed threshold; risk rises with high doses in CrCl <30 mL/min without adjustment. Features: confusion, agitation, myoclonus, seizures; rising creatinine; anaphylaxis / severe rash.

Immediate Actions

- Stop cefazolin immediately - Supportive care

Antidote

No specific antidote — supportive care

Decontamination

IV overdose — supportive; contact poison center for massive error.

Escalation

Benzodiazepines for seizures; correct electrolytes; check renal function and concomitant drugs; hemodialysis / high-flux dialysis for severe neurotoxicity or overdose with renal impairment per nephrology.

Clinical pearls

Common mistakes, resistance logic, and bedside traps

At a glance

FIRST LINE: IV first-generation cephalosporin for MSSA bacteremia (preferred over broader agents when appropriate), streptococci, and peri-operative prophylaxis. DOSE — Mild–moderate infections: 1 g IV q8h; severe infections (e.g., bacteremia): 2 g IV q8h. MAX — Common 8 g/day; selected ICU up to 12 g/day. AVOID — Renal impairment without adjustment; under-dosing deep MSSA infection. ANTIDOTE — None.

Do not miss

- Serious MSSA infection usually needs 2 g IV q8h - Surgical prophylaxis must be within 60 min pre-incision - Re-dose intra-op if prolonged surgery or major blood loss - High-dose without renal adjustment → encephalopathy/seizures - No oral formulation - Not appropriate for MRSA or ESBL risk settings - Weight-based prophylaxis in obesity matters

Clinical pearls

Excellent first-line IV agent for MSSA bacteremia, bone/joint infection, and surgical prophylaxis. Often preferred over antistaphylococcal penicillins because of easier tolerability. For SAB/deep MSSA infection, 1 g q8h is usually inadequate. In prophylaxis, do not continue beyond 24 h post-op unless there is a therapeutic indication. Always check current eGFR before continuing high-dose therapy. 3 AM check: correct bug? correct renal dose? deep MSSA dose high enough? prophylaxis continuing unnecessarily?

Formulation & safety box

  • IV/IM only — no oral step-down
  • Renal dosing non-optional for CKD/dialysis
  • Time-critical surgical prophylaxis — document time and redoses
  • Verify MSSA vs MRSA and ESBL risk before empiric reliance
  • Document β-lactam allergy history before first dose

Pharmacokinetics

- Not orally absorbed - IV bioavailability ~100% - Minimal metabolism - Primarily renal excretion; 60–80% unchanged in urine in first 24 h - Half-life ~1.5–2 h - Half-life prolonged markedly in renal impairment

Mechanism of action

First-generation cephalosporin. Binds penicillin-binding proteins and inhibits peptidoglycan cross-linking. Active mainly against MSSA, streptococci, and some susceptible enteric gram-negatives.

Common brand names

Saudi Arabia

Cefazolin sodium (generic)

Global

Cefazolin for Injection, Cefazolin Sodium, Country-specific branded generics

Common trade names are curated examples only — formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.

Country practice notes

  • Common first-line surgical prophylaxis agent in Gulf hospitals
  • Strong MSSA option where nafcillin/oxacillin availability is limited
  • Widely stocked as generic cefazolin sodium vials across KSA/Gulf
  • Common prescribing error: prophylaxis dose mistimed or not redosed in long surgery
  • Often preferred over antistaphylococcal penicillins for tolerability in MSSA bacteremia/bone infection

References

Saudi Arabia

  • SFDA (Saudi Food & Drug Authority)
  • Saudi National Formulary / MOH (where available)

International

  • WHO Model List of Essential Medicines (verify current edition)
  • US FDA or EU EMA product information (when national SmPC is unavailable)
  • SFDA
  • Saudi MOH surgical prophylaxis protocols
  • Product monographs (Canada/NZ)
  • BNF-style hospital guidance
  • Pharmacovigilance reports on cefazolin anaphylaxis and AGEP
  • Reviews/case series on cefazolin neurotoxicity
  • SFDA
  • Saudi MOH surgical prophylaxis protocols
  • Product monographs (Canada/NZ)
  • BNF-style hospital guidance
  • Pharmacovigilance reports on cefazolin anaphylaxis and AGEP
  • Reviews/case series on cefazolin neurotoxicity