Pharmacy assessment of penicillin allergy can save money, study finds

Researchers have estimated that switching 43 patients from a non-beta-lactam antibiotic to a beta-lactam antibiotic resulted in around $21,000 of potential cost savings in a study on patients with a reported penicillin allergy.

Blister pack of cefalexin

Pharmacy-driven allergy assessments can provide cost savings for patients with a reported penicillin allergy, a study presented at the American Society of Health System Pharmacists’ 54th Midyear Clinical Meeting (9 December 2019) has shown.

The study also found that the assessments improve allergy documentation, and increase use of beta-lactam antibiotics.

Researchers interviewed 63 patients who were admitted to the Baptist Hospital of Miami in the United States. Those with a reported penicillin allergy were chosen in order to clarify their allergy history and optimise antibiotic selection. The researchers also evaluated medication records and outpatient history for prior tolerance to beta-lactam antibiotics, such as penicillin.

Broad-spectrum antibiotics (aztreonam and levofloxacin) were the most commonly prescribed non-beta-lactam antibiotics prior to the allergy assessment. The authors noted that clinicians prefer to save these for when standard treatments are not effective, to ensure the bacteria do not become resistant to the next line of defence. 

For patients with mild-to-moderate penicillin allergies, or those with a prior tolerance to beta-lactam antibiotics, treatment with a beta-lactam antibiotic, such as cephalosporin, was recommended to the prescriber.

Overall, 43 patients were switched from a non-beta-lactam antibiotic to a beta-lactam antibiotic, with a 100% prescriber acceptance rate.

Prior beta-lactam use was confirmed in 57% of patients and allergy documentation was updated in 83% of patients. The researchers also estimated that, over a three-month period, $21,468 of potential cost savings were made.

“The prevalence of this perceived allergy makes our study particularly useful to hospitals and healthcare systems as they look at better patient care and cost reductions,” said Rita Chamoun, clinical staff pharmacist at the Baptist Hospital of Miami and lead author of the study.

“Working together, pharmacists and other medical professionals can find alternatives that work for some patients.

“A multidisciplinary approach is key to optimising therapy in patients with a reported penicillin allergy.”

Neil Powell, consultant antimicrobial pharmacist at the Royal Cornwall Hospital, said that identifying patients with a self-reported penicillin allergy history, and determining whether it is safe to give them penicillin, is an area of “great interest” to many working in antimicrobial stewardship in the UK.

“The wider literature from around the world demonstrates that between 50–80% of patients with self-reported penicillin allergies can be categorised as low risk for future allergic reactions — and by low risk we mean they have the same baseline population risk of anaphylaxis,” he said.

“This study looks at giving patients with a penicillin allergy history a beta-lactam and successfully administers cephalosporins to many, but current data suggest that we could be giving penicillin to the majority of these patients.

“Giving penicillin to patients, if safe to do so, instead of second- or third-line antibiotics is preferable due to the potential risks associated with not giving penicillin: higher risk of Clostridioides difficile-associated diarrhoea; increased length of hospital stay; higher mortality rate; as well as the higher treatment costs.”

Sarah Denman, advanced clinical pharmacist for immunology and allergy at Leeds Teaching Hospitals NHS Trust, said the work supported the need for accurate drug allergy documentation, both in people with documented allergies, but also in the prevention of inappropriate labels being added. 

“It supports the role of pharmacists as key members of the multidisciplinary team to support ongoing work within this area and the multispeciality work being undertaken by the British Society for Allergy and Clinical Immunology Penicillin Taskforce Group, which has dual pharmacy representation,” she said.

Last updated
The Pharmaceutical Journal, Pharmacy assessment of penicillin allergy can save money, study finds;Online:DOI:10.1211/PJ.2019.20207452

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