Implementation of a Pharmacist-Managed Penicillin Skin Testing (PST) Service at a Community Teaching Hospital

Abstract

Background. Penicillin allergies routinely result in the use of alternative antibiotics, which has shown to increase cost, length of stay, and the incidence of multidrugresistant organisms. The goal of this study was to describe how a pharmacist-managed penicillin skin testing (PST) service could be implemented to optimize antimicrobial therapy in patients who report a penicillin allergy. Methods. The core members trained to conduct a PST were an infectious diseases (ID) physician, ID pharmacist, PGY2 ID pharmacy resident, and 4 PGY1 pharmacy practice residents. Patients were identified through ID physician consult and antimicrobial stewardship team rounds. Patients more than 18 years old were considered for skin testing if they had a history of a type 1 (or unknown) allergic reaction to penicillin that occurred greater than 5 years ago and a beta-lactam antibiotic was indicated. Patients were excluded for the following reasons: pregnancy, non-type 1 allergic reaction, recent use of anti-histamines, and severe immunosuppression. The primary objective was to reduce the use of alternative antimicrobials such as carbapenems, vancomycin, and fluoroquinolones. Secondary objectives include tolerability of the PST and beta-lactam therapy. Results. Of 15 patients that underwent skin testing, 14 results were negative and 1 was inconclusive (no response to positive histamine control). No severe reactions occurred during the skin test or beta-lactam challenge. Thirteen patients of 14 that completed skin testing were transitioned to a preferred beta-lactam antibiotic. The most common antibiotics prior to PST were carbapenems (n = 6), vancomycin (n = 6), and fluoroquinolones (n = 2). The number of days of alternative antibiotics avoided ranged from 7 to 180, with a mean of 31.3 days and median of 13 days. Conclusion. A pharmacist-managed penicillin skin testing service is a viable tool for an antimicrobial stewardship program in a community hospital setting. Further studies are needed to assess patient outcomes and cost-benefit.