Single-dose pharmacokinetics of cefpirome in patients with renal impairment

The pharmacokinetic parameters of cefpirome (HR 810) were examined in 22 patients with different degrees of renal impairment. HPLC was used to analyze samples of blood and urine for cefpirome; and enzymatic assay of creatinine in serum and urine was used to assess kidney function. Creatinine clearance correlated linearly with both total and renal clearance of cefpirome. The loss of kidney function resulted in a decreased renal clearance, whereas the volume of distribution remained the same. This result led to an increase in the terminal half-life of the drug, from 2 hours in healthy subjects to 14 1/2 hours in patients with uremia. This increase also resulted in a prolonged high serum concentration well above the minimum inhibitory concentration. The following dosages are thus recommended: (1) creatinine clearance greater than 50 ml/min: normal daily dose, (2) creatinine clearance from 20 to 50 ml/min: 50% of normal daily dose, and (3) creatinine clearance less than 20 ml/min: 25% of normal daily dose. An initial loading dose of 1 gm, independent of renal function, is advised. Cefpirome was safe and well tolerated.