Pharmacokinetics of cefadroxil in patients with impaired renal function

The pharmacokinetics of cefadroxil were studied in patients with different degrees of renal impairment after a single oral dose of 1000 mg. The standard open one-compartment model was used to determine the pharmacokinetic data. In normal subjects, the mean peak level was 25·72 mg/l and occurred at 1·20 h. The elimination half-life averaged 1·39 ± 0·06 h and 93% of the dose was recovered in 24 h urines. Renal clearance (167 ml/min/1 73 m2 exceeded creatinine clearance. In uraemic patients the peak serum levels were higher (20–60 mg/l) and occurred later (2 to 6 h). The elimination half-life increased in relation to the degree of renal failure moderately where the creatine clearance was 25 to 50 ml/l min/1·73 m2 reaching 25 h in haemodialysis patients. The apparent volume of distribution was not significantly modified in renal impairment (≃20·1). Haemodialysis increases the elimination of cefadroxil, the elimination half-life during dialysis being 3·37 ± 0·53 h. The elimination rate constant (Kel) correlated well with renal function. The dosage regimen of cefadroxil should be adjusted according to the severity of renal failure.