Pharmacology of Cefazolin in Patients with Normal and Abnormal Renal Function

Levels of cefazolin in serum and urine were determined after a 500-mg parenteral dose in patients with normal and various degrees of compromised renal function. The mean peak concentration in serum, corrected for body weight, did not differ significantly among patients with different endogenous creatinine clearances (Cer). The urinary concentration and percentage of the dose excreted in the urine within the first 4 or 6 hr after administration of cefazolin decreased significantly in patients with compromised renal function, but the urinary concentration of cefazolin was adequate, even in patients with Cer of 12–17 mllmin, to treat urinary-tract infection caused by cefazolin-sensitive pathogens. The half-life (T1/2) of cefazolin in serum increased significantly in patients with Cel ⩽ 26 mll min. Mean T1/2 was 2.2 hr with Cer of 95–147 ml/min, 2.4 hr with Cer of 56–80 ml/min, 6.8 hr with Cer of 26 ml/min, 12.0 hr with Cer of 12–17 ml/min, and 56.6 hr with Cer < 5 mll min. Hemodialysis significantly lowered the T1/2 in serum to 8.8 hr in patients with Cer