Pharmacokinetics of cefaclor in normal subjects and patients with chronic renal failure.

We studied the pharmacokinetics of cefaclor, a new cephalosporin antibiotic, in normal subjects and subjects with chronic renal failure. Cefaclor was largely, but not entirely, eliminated by the kidneys. The cefaclor half-life in normal subjects was 40 to 60 min; in subjects with essentially no renal function, it increased to 3 h. In normal subjects, 50 to 70% of a 250-mg dose was excreted in the urine within 8 h. The linear relationship between the elimination constant and creatinine clearance allowed the construction of a useful dosage modification nomogram.