The Clinical and Financial Impact of a Pharmacist-Driven Penicillin Skin Testing Program on Antimicrobial Stewardship Practices

Purpose: Pharmacist-led penicillin skin testing (PST) was incorporated into antimicrobial stewardship at a community hospital to increase use of optimal antimicrobial therapy, reduce use of broad-spectrum agents, and reduce antimicrobial therapy-related costs. Methods: A clinical decision support software alert identified qualifying patients with penicillin allergies. Patients receiving a nonoptimal antimicrobial agent were prioritized for PST. Patients were excluded if they reported a history of extreme hypersensitivity to a penicillin agent, such as Stevens-Johnson syndrome, toxic epidermal necrolysis, or mucocutaneous eruption with epidermal detachment. Pediatric patients less than 18 years old and pregnant patients were excluded. Data collected for each patient included the medication that precipitated the reaction; reaction type; age when the reaction occurred; current antibiotic therapy; indication for therapy; preferred antimicrobial agent; days of therapy on each agent used; positive, negative, or ambiguous PST result; recent antihistamine use; and any adverse events that occurred. Outcomes of the PST results, pharmacist interventions made after PST, and resulting cost savings to patients were all reported. Results: Among 31 patients tested, 27 were negative for penicillin allergy, 1 was positive for penicillin allergy, and 3 yielded an indeterminate test. Pharmacist recommendation to change therapy based on PST results was accepted in 13 of 15 patients where recommendations were made. Cost savings in antimicrobial therapy alone for patients who received PST was US $74.75 per day. Conclusion: Pharmacist-driven PST provided opportunities to clarify allergies, optimize antimicrobial therapy, and save antimicrobial therapy-related costs to patients.