Retrospective evaluation of piperacillin use in a university hospital

A retrospective review was conducted to evaluate the appropriateness of empiric and definitive piperacillin use and to determine if less expensive, more appropriate antibiotics could have been used. The criteria were approved by the chief of infectious diseases and the drug utilization review committee at this institution. One hundred courses of piperacillin use in adult patients were reviewed. Therapy was categorized as appropriate in 78 of the 100 courses: 21 were appropriate empiric, 32 were appropriate empiric changed to definitive due to culture and sensitivity reports, and 25 were appropriate definitive. Reasons for this high percentage of appropriate use include: 1) 40% of the infections involved Pseudomonas aeruginosa; 2) 18% of the organisms that were sensitive to piperacillin were resistant to ticarcillin and mezlocillin; and 3) 64% of the courses of therapy involved critically ill patients with diagnoses such as neutropenia secondary to cancer chemotherapy, burns, sepsis, and hospital-acquired pneumonia. Although only 19.7% of the 11,845 grams of piperacillin used were categorized as inappropriate, the cost is relatively high (annualized to $19,648) and cost savings could be realized if piperacillin use were monitored more closely.