Is renal function the only determinant in the elimination of ceftazidime?

Ceftazidime is a third-generation cephalosporin that is eliminated primarily via the kidneys. Several studies have indicated that dosage adjustment is necessary in patients with renal disease. The correlation between the glomerular filtration rate and half-life (t 1/2) developed by Norrby and co-workers was used to evaluate, in three patients, the hypothesis that renal function is the principal determinant in excretion of the ceftazidime. Results obtained indicate that although the correlation appeared valid for a patient with chronic renal failure it did not predict patterns of ceftazidime elimination in two granulocytopenic patients with lymphoma. Therefore, caution should be exercised when employing Norrby's correlation for adjusting ceftazidime dosage for patients with certain disease states.