Use of a Penicillin Allergy Screening Algorithm and Penicillin Skin Testing for Transitioning Hospitalized Patients...

Penicillin allergy is the most commonly reported antibiotic allergy. Avoidance of β-lactam antibiotics in hospitalized patients leads to the use of second-line therapies.

The utility of a penicillin allergy history algorithm (PAHA) and subsequent penicillin skin testing (PST) in transitioning hospitalized patients from second- to first-line antibiotic therapy is described.

Through an electronic medical record report, pharmacists identified adult inpatients with penicillin allergy receiving moxifloxacin, intravenous vancomycin, aztreonam, daptomycin, or linezolid, in which a β-lactam antibiotic was preferred. The PAHA was administered to identify patients for PST. Skin-test negative patients were transitioned to first-line β-lactam antibiotic therapy.

Fifty patients consented to the study. Historical reactions included hives (16 patients, 32%), angioedema (15, 30%), anaphylaxis (6, 12%), unknown (6, 12%), rash (6, 12%), and dyspnea (1, 2%). Pre-PST antibiotic regimens included vancomycin (82%), aztreonam (22%), moxifloxacin (6%), daptomycin (4%), and/or linezolid (2%). Forty-seven patients (94%) were skin-test negative and were subsequently transitioned to a β-lactam antibiotic. Two patients were skin-test positive and one was histamine nonreactive. No patients experienced an immediate adverse reaction when challenged with a penicillin-based antibiotic. A total of 982 days of second-line antibiotic therapy and at least 23 hospital days to administer the antibiotic were avoided.

The use of the PAHA and subsequent PST is a safe, effective multidisciplinary intervention that facilitates the transition to β-lactam antibiotics. Our approach is unique in that it prioritizes patients based on the use of second-line antibiotics, and then applies an algorithm to determine eligibility for PST.