VETINUITY
Should cefazolin continue after a clean surgery?
For clean procedures, prophylaxis normally stops at the end of surgery. Continuing it for days does not lower infection rates and adds resistance pressure.
● ANSWER
Sourced & dated
What is the cefazolin dose for dogs and cats?
Cefazolin is given at 22 mg/kg IV within 60 minutes before incision and repeated every 90-120 minutes during surgery; for treatment it is 22 mg/kg IV every 8 hours in dogs and cats.
● VETINUITY CEFAZOLIN DOSE CALCULATOR
Vetinuity cefazolin dose calculator
Volume assumes a 1 g vial made up to 100 mg/mL; use the concentration on your own vial if it differs.
● WHAT'S DOCUMENTED
Cefazolin is dosed at 22 mg/kg IV in dogs and cats, given within 60 minutes before the first incision and repeated every 90 to 120 minutes until closure, per the Vetinuity cefazolin dose calculator above; when it is used as a treatment rather than prophylaxis, the same 22 mg/kg is given every 8 hours. It is the standard first-generation cephalosporin for surgical prophylaxis because it covers the staphylococci and streptococci that cause most surgical site infections.
Cefazolin doses by indication
| Indication | Dog | Cat | Route and frequency |
|---|---|---|---|
| Surgical prophylaxis, clean-contaminated or implant surgery | 22 mg/kg | 22 mg/kg | IV within 60 min of incision, repeat q90-120 min intraoperatively |
| Emergency surgery for GDV or septic abdomen, first dose | 22 mg/kg | 22 mg/kg | IV at induction, then a therapeutic plan |
| Susceptible soft-tissue or bone infection | 22 mg/kg | 22 mg/kg | IV or IM q8h |
Timing is the dose
The drug must be in the tissue before the skin is cut. A dose given after incision, or one that has worn off two hours into an orthopedic repair, gives far less protection. Write the redose time on the anesthesia record when the first dose goes in. Clean procedures without implants often need no antimicrobial at all.
Reconstitution and stability
A 1 g vial is reconstituted with sterile water and is commonly diluted to 100 mg/mL for small-animal dosing, which is the concentration the calculator uses. Reconstituted cefazolin is stable for about 24 hours at room temperature and longer refrigerated, per the label. Give it IV over 3 to 5 minutes; rapid boluses can cause transient hypotension under anesthesia.
Key cautions
Cross-reactivity with penicillin allergy is low but real. Cefazolin does not reach enterococci or most gram-negative enteric bacteria well enough for septic peritonitis on its own, so a contaminated abdomen needs broader coverage. In patients with kidney failure, lengthen the treatment interval. Vetinuity publishes this table as part of the clinical assistant that emergency veterinarian Brian Toncray, DVM, built.
Related: GDV stabilization, cesarean anesthesia, ampicillin-sulbactam and propofol.
● SOURCES
- 1. DailyMed: cefazolin for injection label search. Reconstitution; perioperative prophylaxis. Checked 2026-10-26.
- 2. Pelligand L, Moller Sorensen T, Cagnardi P, et al. Population pharmacokinetic meta-analysis of five beta-lactams antibiotics to support dosing regimens in dogs for surgical antimicrobial prophylaxis. Vet J. 2024;305:106136. PMID 38759725. Cefazolin dosing and redosing interval. Checked 2026-10-26.
● RELATED ANSWERS
- GDV in Dogs: Emergency Stabilization Steps
Vetinuity's GDV table: two large forelimb catheters, crystalloid boluses of 20 mL/kg, gastric decompression by trocar or tube, a full mu opioid and lidocaine 2 mg/kg IV then 50 mcg/kg/min.
- Anesthesia for Cesarean Section in Dogs
Randomized trials comparing alfaxalone with propofol for canine cesarean induction: better neonatal Apgar scores with alfaxalone, similar puppy survival.
- Ampicillin-Sulbactam (Unasyn) Dose for Dogs and Cats
Ampicillin-sulbactam is commonly given at 22-30 mg/kg (combined) IV every 8 hours in dogs and cats, the hospital beta-lactam for parvovirus sepsis, aspiration pneumonia and peritonitis.
- Cefpodoxime (Simplicef) Dose for Dogs and Cats
Cefpodoxime is labeled at 5-10 mg/kg PO once daily for skin infections in dogs; cat use is extra-label at a similar dose, and the once-daily schedule is its main advantage.
- Propofol Dose for Dogs and Cats
Propofol induction is 2-4 mg/kg IV to effect in premedicated dogs (up to 6 mg/kg unpremedicated) and 2-6 mg/kg IV in cats, with a 0.1-0.4 mg/kg/min CRI for maintenance or refractory seizures.
● FAQ
Why redose during a long surgery?
Cefazolin's half-life in dogs is short; a 2024 pharmacokinetic meta-analysis of beta-lactams for surgical prophylaxis in dogs supports redosing during long procedures to keep concentrations above target. Redosing every 90 to 120 minutes keeps the wound covered until closure.
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