Tech & Health

September 29, 2022

Penicillin delabeling initiative expanding to more patient care areas

Efforts to correct mistaken or outdated penicillin allergy records are destined to spread to more patient care areas at Vanderbilt University Medical Center.

Given the stakes for patients and for public health, experts say current efforts to correct mistaken or outdated penicillin allergy records are destined to spread to more patient care areas at Vanderbilt University Medical Center.

It turns out that a great majority of people whose health records indicate penicillin allergy will not have an allergic reaction to penicillin. Pending a simple risk assessment, so-called penicillin allergy delabeling in a majority of cases involves giving patients a single oral dosage of penicillin, called a challenge, and keeping them under observation for about an hour.

Cosby Stone Jr., MD, MPH

“Among some 300 of these low-risk challenges undergone by inpatients with reported penicillin allergies, exactly two had a rash appear after we gave them a dose,” said allergy and immunology specialist Cosby Stone Jr., MD, MPH, assistant professor of Medicine.

According to the U.S. Centers for Disease Control and Prevention, while an estimated 10% of U.S. patients report having a penicillin allergy, fewer than 1% of the population is truly allergic to penicillin, and 80% of those who have had an allergic reaction to penicillin will lose their sensitivity within 10 years.

“There’s such good evidence now that, in giving a challenge dose of penicillin to a low-risk patient, the chance of reproducing that once-upon-a-time supposed allergic reaction is almost zero,” said infectious diseases specialist Elizabeth Phillips, MD, the John A. Oates Chair in Clinical Research and professor of Medicine.

Elizabeth Phillips, MD

Vanderbilt studies recently published by Stone, Phillips, Grace Koo, MD, Joanna Stollings, PharmD, and colleagues showed that intensive care patients, including those with COVID-19, can safely be delabeled at the point of care using a single oral challenge.

To support delabeling, VUMC pharmacists use a penicillin allergy risk stratification tool developed by Stone, Phillips and colleagues; adult medical ICU patients reporting the allergy are by default assessed for risk by a pharmacist and tested as appropriate, and upon referral pharmacists also provide this assessment and testing throughout Vanderbilt University Hospital.

Studies suggest that 75% of patients with penicillin allergy labels in their health records acquired them by age 3. Stone and Phillips say that itching and hives posed by viral infections in children have a way of mistakenly getting documented as penicillin allergy — this when antibiotics are not indicated for viral infections.

“We need more thoughtful and respectful use of antibiotics,” Phillips said. “Think hard before you give an antibiotic to a child who likely has a viral infection. And if a child does get a rash during a viral infection, when they happen to have gotten an antibiotic, seriously consider that that may not be a drug reaction.

“Those children are going to grow to have legitimate need of antibiotics. Your innocent label of penicillin allergy acquired when you were 5 years old can later in life have serious consequences, during pregnancy or before surgery, where penicillins and antibiotics in the related cephalosporin family have proven to be effective and safe.”

Beyond the potential for immediate harm (to patients with an erroneous allergy label who may consequently be given a less effective therapy), there’s a tandem concern that inappropriate use of antibiotics, especially of the more powerful broad-spectrum alternatives to penicillin, needlessly accelerates drug resistance, dragging down public health.

“The issue with antibiotics,” Stone said, “is that they’re sort of like groundwater in the western part of the United State: the more we tap into it, the less we’re going to have it when we really need it and we’re up against drug resistant infections.”

For adults, VUMC’s Drug Allergy Clinic provides penicillin allergy testing, with a main location in Nashville and four satellite locations around Middle Tennessee. For children, testing is provided by Pediatric Allergy and Immunology, with locations in Nashville and Murfreesboro.

“To patients the message would be, ask your doctor whether your penicillin allergy is affecting your ability to get the right antibiotic at the right time. And the message to doctors would be, pay attention to the ways in which penicillin allergies are keeping you from doing the thing you actually want to do,” Stone said.

For antibiotic treatment recommendations, visit the website of the Vanderbilt Antimicrobial Stewardship Program (employee login required).