Ceftriaxone to Cefazolin Dose Conversion Guidelines

Dosing Equivalence

• The American Heart Association guidelines recommend ceftriaxone 100 mg/kg/day divided every 12 hours or 80 mg/kg/day every 24 hours (up to 4g daily maximum) for infective endocarditis, while cefazolin is recommended at 100 mg/kg/day divided every 8 hours (up to 12g daily maximum) 1, 2
• For a standard adult receiving ceftriaxone 2g once daily, the equivalent cefazolin dose is approximately 6g daily divided into three doses (2g every 8 hours) 1, 2
• The American Heart Association guidelines suggest that ceftriaxone 2g daily is equivalent to cefazolin 6-8g daily (2g every 8 hours) for serious infections such as endocarditis and meningitis 1, 2

Clinical Context Considerations

• The maximum cefazolin dose can reach 12g daily for severe infections, according to the American Heart Association guidelines 1, 2
• Cefazolin is not appropriate for CNS infections (meningitis) due to poor CSF penetration, whereas ceftriaxone achieves excellent CNS concentrations 3