Hospital Pharmacy - February 2020 - 58

817917
research-article2018

HPXXXX10.1177/0018578718817917Hospital PharmacyHarmon et al

Original Article

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

Hospital Pharmacy
2020, Vol. 55(1) 58-63
© The Author(s) 2018
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https://doi.org/10.1177/0018578718817917
DOI: 10.1177/0018578718817917
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Stacy Harmon1,2 , Thomas Richardson2, Heidi Simons2,
Summer Monforte2, Shea Fanning2,
and Kaitlyn Harrington2

Abstract
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.
Keywords
allergy, penicillin, pharmacist, stewardship, skin test

Introduction
Current literature estimates that 10% of patients report an
allergy to penicillin.1 Of these patients, more than 90% are
likely tolerant to penicillin and cephalosporin agents.1-3 In
addition, IgE antibodies can decline over time, and therefore,
even in patients with a history of IgE-related reactions to a
penicillin agent, the patient may have a negative penicillin
skin test.1 These IgE-related reactions are typically immediate and often manifest in systemic fashion such as with anaphylaxis or urticarial rashes without blistering. Penicillin
skin testing (PST) is a method of clarifying these allergies,
allowing for more definitive antibiotic treatment decisions.
In a recent study comparing methods of clarifying penicillin
allergies, 43 patients were given skin tests, and all 43 tests
were negative. Negative penicillin skin tests resulted in a significant increase in the usage of penicillin and cephalosporin
agents, as 72% of these patients who received PST moved on

to receive a penicillin or cephalosporin for treatment and
experienced no significant adverse effects.3
One multicenter evaluation of beta-lactam skin testing
revealed that 99% of patients who received a beta-lactam
after a negative skin test tolerated therapy, attesting to the
safety of the results of skin testing.4 In addition, there is evidence that patients remain nonreactive even after repeated
courses of beta-lactams.5
Evidence also demonstrates increased rates of infections
by Clostridium difficile, methicillin-resistant Staphylococcus
1

Aurora St. Luke's Medical Center, Milwaukee, WI, USA
St. Peter's Health, Helena, MT, USA

2

Corresponding Author:
Stacy Harmon, Aurora St. Luke's Medical Center, 2900 W Oklahoma
Avenue, Milwaukee, WI 53215, USA.
Email: stacylharmon@gmail.com
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Hospital Pharmacy - February 2020

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