Initiative to reduce aztreonam use in patients with self-reported penicillin allergy: Effects on clinical outcomes and antibiotic prescribing patterns

Purpose. Evaluation of the clinical impact of a pharmacist led-penicillin allergy assessment initiative to enhance antibiotic selection is reported. Methods. A retrospective analysis was conducted on patients with a self-reported penicillin allergy (SRPA) at a 529-bed community teaching hospital and compared clinical response rate before and after implementation of a penicillin allergy assessment initiative, consisting of pharmacy staff education and pocket card development. Patients admitted with SRPA who received antibiotics with gram-negative coverage for at least 48 hours were included. The primary outcome was the clinical response rate of penicillin-allergic patients determined preimplementation and postimple-mentation of the initiative and was based upon improvement in signs and symptoms of infection. Secondary outcomes included antibiotics used, antibiotic durations, length of stay, survival rate, antibiotic discontinuation rate, and Clostridium difficile infection rate. Results. A total of 280 patients were reviewed. Clinical response rate improved after implementation of the initiative (p = 0.047). There were significant differences in the type of antibiotics prescribed between the preimplementation group and the postimplementation group: increased cephalosporin use (p < 0.001), decreased aztreonam use (p = 0.017), and lower fluoroquinolone use (p = 0.008). Median length of stay (p = 0.943), inhospital mortality rate (p = 0.173), and C. difficile infection rate (p = 0.426) were similar before and after implementation of the initiative. Conclusion. After implementation of an initiative to encourage the use of cephalosporins rather than aztreonam in patients with SRPA, the rate of clinical response and cephalosporin use increased and rates of exposure to aztreonam and fluoroquinolones decreased.