Effect of hemodialysis and renal failure on serum and urine concentrations of cephapirin sodium.

Six patients undergoing chronic hemodialysis and 10 patients with chronic renal insufficiency hospitalized for nondialytic therapy received 1.0 g of cephapirin sodium by the intravenous route. The concentrations of cephapirin in arterial and venous plasma, dialysate, venous blood, and urine were measured during the ensuing 6 hr. The serum half-life of cephapirin was 105 to 108 min for the dialyzed patients and 95.9 min for the nondialyzed patients. Dialysis removed 22.8% of the administered dose. Nondialyzed patients excreted 19.5% of the administered dose in the urine. The concentration of cephapirin in the urine of all nondialyzed patients exceeded 50 mug/ml. The recovery of cephapirin in the urine collected for 6 hr after injection was from 34 to 770 mg (mean 195 mg). To maintain a concentration of cephapirin in the blood and urine which exceeds the minimal inhibitory concentration for most gram-positive and gram-negative microorganisms, nondialyzed patients should receive 15 to 18 mg of cephapirin per kg every 12 hr. Dialyzed patients should receive the same dose just prior to dialysis and every 12 hr thereafter.