Ceftazidime dosing in the elderly: economic implications

OBJECTIVE: This study evaluated the prevalence and resulting costs of ceftazidime dosing in excess of product labeling recommendations in elderly hospitalized patients. Ceftazidime is a beta-lactam antibiotic excreted via glomerular filtration. According to product labeling, ceftazidime dosing can frequently be decreased in the elderly because glomerular filtration declines with age. METHODOLOGY: A multicenter, retrospective utilization audit involving 11 US academic medical centers examined 221 medical records of patients 65 years of age or older receiving ceftazidime (any brand, any indication). The creatinine clearance of each patient was estimated using the Cockcroft-Gault formula. RESULTS: Renal insufficiency, defined as an estimated creatinine clearance of less than 50 mL/min, was present in 111 of the patients (50 percent). Ceftazidime dosing in excess of product labeling recommendations was noted in 75 of those 111 (68 percent). The cost of excess ceftazidime dosing for those 75 patients (i.e., extra drug acquisition, preparation, administration) was $13,822.50. CONCLUSIONS: Although the dosage of ceftazidime required in a specific patient is based on many factors, ceftazidime is frequently overdosed in the elderly because renal function is not considered. Ceftazidime dose-adjustment in the elderly, based on the estimated creatinine clearance, can lead to cost savings. In the US, where hospital reimbursement by Medicare is based on diagnosis, institutions can realize direct cost savings.