Prospective drug utilization evaluation of three broad-spectrum antimicrobials: cefepime, piperacillin-tazobactam and meropenem

BACKGROUND: Cefepime, piperacillin-tazobactam and meropenem are among the broadest-spectrum and most expensive antimicrobials. AIM: To evaluate guidelines for appropriate use of these drugs. METHODS: We developed guidelines for use of these antibiotics, and conducted a two-phase drug utilization evaluation. We included all patients who received one of the study drugs during two 3-month periods, with an educational intervention in the intervening period. Appropriateness was determined for initiation of treatment, and for adaptation or continuation of established treatment. RESULTS: Overall, 205 patients received 271 courses with one of these antibiotics, for a total of 709 defined daily doses (DDD) of cefepime, 543 of piperacillin-tazobactam, and 680 of meropenem (8.3, 6.3 and 7.9 DDD/1000 admission days, respectively). Of these 271 courses, 234 were appropriate (86%). Treatment was continued for > or =5 days in 60%, of which 88% were appropriate (NS). Of the 271 courses, 210 (77%) were empirical (83% appropriate), while 61 (23%) were based on a relevant culture result (97% appropriate) (p < 0.001). Appropriateness differed significantly between departments (p < 0.001), and between the two phases (p < 0.001). The major difference between the two surveys was a decrease in meropenem usage (p < 0.05). DISCUSSION: The vast majority of courses with cefepime, piperacillin-tazobactam and meropenem are empirically selected and continued, underlying the importance of an optimal initial choice. Antibiotic guidelines, in conjunction with formal infectious disease consultation, can contribute to more appropriate use of these drugs.