1st Generation Cephalosporin (Surgical Antibiotic Prophylaxis) Pregnancy: Compatible — cephalosporins widely used in obstetric and gynaecological surgery

Cefazolin (Surgical Prophylaxis)

Brand names: Kefzol

Adult dose

Dose: Surgical prophylaxis: 1–2 g IV single dose at induction (30–60 min before incision). Repeat 1–2 g IV every 4h if surgery >4h or blood loss >1.5L.

Route: IV

Frequency: Single dose at induction; repeat if long surgery

Max: 3 g single dose (morbid obesity)

First-line antibiotic prophylaxis for most clean/clean-contaminated surgery (UK: cefuroxime often used instead). Good coverage for Staphylococcal and streptococcal surgical site organisms.

Paediatric dose

Dose: 30 mg/kg

Route: IV

Frequency: Single dose at induction; repeat every 4h in prolonged surgery

Max: 2 g per dose

Concentration: 1 g vial mg/ml

Neonates: 25 mg/kg IV every 12h. Children: 20–30 mg/kg IV before incision.

Dose adjustments

Renal

Reduce dose in severe renal impairment (eGFR <10)

Hepatic

No dose adjustment required

Paediatric weight-based calculator

Patient weight (kg)

Neonates: 25 mg/kg IV every 12h. Children: 20–30 mg/kg IV before incision.

Clinical pearls

Timing is critical: must be given 30–60 min before skin incision for peak tissue levels at time of incision
Redosing: repeat dose at 4h intervals or after blood loss >1.5L — do NOT give postoperative 'prophylactic' courses (no evidence, increases resistance)
WHO SSI guidelines 2016: single pre-incision dose is sufficient for most procedures
Morbid obesity: use weight-based dosing (30 mg/kg, max 3 g) — standard dose provides subtherapeutic tissue levels in obese patients

Contraindications

Cephalosporin allergy
Immediate penicillin hypersensitivity (cross-reactivity ~2% — use alternatives)

Side effects

Diarrhoea
Allergic reactions
C. difficile (rare)
Phlebitis at IV site

Interactions

Anticoagulants — mild increase in INR (monitor warfarin)

Monitoring

Allergic reactions peri-operatively
Wound infection surveillance (post-operative)
Renal function in prolonged use

Reference: BNFc; BNF; WHO SSI Guidelines 2016; SIGN 104 Antibiotic Prophylaxis in Surgery. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways