Cefotaxime vs Ceftriaxone Pharmacokinetic Differences
Cefotaxime and ceftriaxone are third-generation parenteral cephalosporins with overlapping antibacterial activity. [1][2]
Elimination Half-Life and Dosing Frequency
Cefotaxime has an elimination half-life of approximately 1 hour. [1] Ceftriaxone has an elimination half-life approximately 5.8 to 8.7 hours with dosing often administered once daily in many clinical regimens. [2]
Routes of Elimination
Cefotaxime is substantially excreted by the kidney. [1] Ceftriaxone is excreted in both urine and bile, with 33% to 67% of a dose excreted in urine as unchanged drug and the remainder secreted in bile and ultimately found in feces as microbiologically inactive compounds. [2]
Calcium-Containing Solution Compatibility
Ceftriaxone is contraindicated in neonates (≤28 days) who require or are expected to require treatment with calcium-containing IV solutions, including continuous calcium-containing infusions such as parenteral nutrition, due to risk of ceftriaxone–calcium precipitation. [3] Ceftriaxone should not be reconstituted or further diluted using diluents containing calcium such as Ringer’s solution or Hartmann’s solution due to risk of precipitation. [3]
Dialyzability
Ceftriaxone is not removed to any significant extent from plasma by hemodialysis. [4] Cefotaxime is known to be substantially excreted by the kidney, which increases the importance of renal function for dosing safety. [1]
Practical Selection Differences
Ceftriaxone is commonly preferred when longer dosing intervals are advantageous due to its substantially longer elimination half-life and dual renal–biliary disposition. [2] Cefotaxime may be preferred when a shorter half-life regimen is desired and renal function is expected to support safe clearance. [1]