A pharmacy-driven assessment found more than half of patients with reported penicillin allergies were able to take antibiotics from the same drug class, rather than resorting to substitutes that may have downsides.1,2 Researchers also found that substitution saved 1 hospital nearly $21,500 by switching 43 patients over 3 months.1

Results of the study—titled “Improving penicillin allergy documentation and its effect on antibiotic prescribing at a community hospital”—were presented Monday at the ASHP (American Society of Health-System Pharmacists) 54th Midyear Clinical Meeting and Exhibition in Las Vegas.1,2

Penicillin is among a variety of antibiotics in a class known as beta-lactams, and patients who report allergies to penicillin are often treated with broad-spectrum non-beta-lactam alternatives. These alternatives are often more expensive, and associated with more adverse effects, factors that potentially limit the advantages of antimicrobial stewardship.1

Penicillin allergies, reported by up to 10 % of the population, are the most common drug allergy.1,2 However, the study’s investigators—pharmacists at Baptist Hospital of Miami—believe that true penicillin allergies are actually rarer, with an overall estimated frequency of less than 0.05%, noting that the high prevalence of reported penicillin allergies may be due to inaccurate allergy documentation.2

“The prevalence of this perceived allergy makes our study particularly useful to hospitals and health care systems as they look at better patient care and cost reductions. Working together, pharmacists and other medical professionals can find alternatives that work for some patients. A multidisciplinary approach is key to optimizing therapy in patients with a reported penicillin allergy,” said the study’s lead author Rita Chamoun, PharmD, clinical staff pharmacist at Baptist Hospital of Miami, in a prepared statement.1

The investigating pharmacists interviewed 63 eligible patients with reported allergies for the study, from February 6, 2019 to April 30, 2019.2 The investigators then carefully reviewed their medication history prior to verifying orders for substitute antibiotics.1,2

Over 3 months, the investigators found that 68% of the studied patients had previously had success using other beta-lactams, most often cephalosporins. Pharmacists recommended switching to a beta-lactam antibiotic with 100% prescriber acceptance.1

Aztreonam and levofloxacin were the most commonly prescribed non-beta-lactam antibiotics prior to the allergy assessment. Clinicians prefer to save these broad-spectrum antibiotics for situations where standard treatments are not effective to ensure the bacteria do not become resistant to this next line of defense, according to the authors. 1

“By improving penicillin allergy documentation, and encouraging both pharmacists and prescribers to thoroughly evaluate allergies and prior cephalosporin use, the use of non-beta-lactam alternatives can be reduced significantly,” Chamoun said.1

Authors noted that the study does not suggest that every patient with a penicillin allergy can take cephalosporins, but instead concluded that it is important to thoroughly evaluate allergy documentation and prior beta-lactam use.

“While our study focused on the use of a pharmacy-driven allergy assessment to reduce non-beta-lactam antibiotic use, we also aimed to improve allergy documentation,” Chamoun said. “We found that improving allergy documentation goes hand-in-hand with optimizing selection of antibiotic therapy.”1

Secondary outcomes of the study included cost of therapy of antibiotic recommended by pharmacist compared to the agent(s) initially selected by the prescriber, prescribing trends before and after the allergy assessment, and adverse events.2

  1. Pharmacy Assessment of Penicillin Allergies Finds Safe, Less-Expensive Options [news release]. Las Vegas, NV; December 9, 2019: ASHP [email]. Accessed December 9, 2019. 
  2. Chamoun R, Bendyk O, Gopalani R, Montes A, Wolfel T. Improving penicillin allergy documentation and its effect on antibiotic prescribing at a community hospital. Presented at: ASHP 54th Midyear Clinical Meeting and Exhibition; Las Vegas, NV. December 9, 2019.