Pharmacokinetics of ceftazidime, alone or in combination with piperacillin or tobramycin, in the sera of cancer patients.

We administered 2 g of ceftazidime intravenously every 8 h to cancer patients for the empiric therapy of febrile episodes. Ceftazidime was administered as monotherapy for patients with granulocyte counts in excess of 1,000/microliter. Febrile, neutropenic patients were randomized to also receive either piperacillin or tobramycin. The pharmacokinetic profile of ceftazidime during a steady-state dosing interval was ascertained in 21 patients. No differences were seen between groups for any of the pharmacokinetic parameters examined. As expected, the observed half-life was longer, the serum clearance was smaller, and the volumes of distribution were larger than in previously reported studies of volunteers. Serum concentrations remained above the MIC for inhibition of 90% of strains of the most common bacteremic pathogens seen in our cancer center for the entire 8-h dosing interval.