Comparison of Ceftazidime and Cefamandole Pharmacokinetics and Blister Fluid Concentrations

Eight healthy male volunteers received 1 g of either ceftazidime or cefamandole as an intravenous infection. Serial blood samples were taken over the next 8 h. Urine samples were collected over 24 h. Levels of these antibiotics were measured in the fluid of blisters resulting from application of cantharides. The concentration of ceftazidime in serum at 0.25 h after intravenous injection was 83.3 micrograms/ml. The serum half-lives for the respective drugs were 1.8 and 0.8 h. The mean apparent volume of distribution of ceftazidime (13.6 liters) was greater than that of cefamandole (9.8 liters). Plasma clearance was 111 ml/min for ceftazidime and 216 ml/min for cefamandole. The maximum blister fluid concentration of ceftazidime was 45.9 micrograms/ml, and that of cefamandole was 22.1 micrograms/ml. The relative availability of each drug in blister fluid compared with serum was similar.