Misreported Penicillin Allergies Lead to Increased Risk of Infection, Antibiotic Resistance

Penicillin is the most commonly reported drug allergy, with 10% of Americans claiming to be allergic, bu it is actually much less common than people believe. National Penicillin Allergy Day takes place every year on September 28—the anniversary of the drug's discovery—to bring awareness to those who have a true allergy and identify those who do not.¹

Falsely believing one has an allergy to penicillin may be harmful, as inaccurate diagnoses can increase medical costs, lead to adverse effects among patients, and contribute to the resistance of key antibiotics, according to a study published by the BMJ.²

Unverified penicillin allergies cost both patients and their health care systems millions each year. Patients with penicillin allergies pay as much as 63% more for antibiotics than those without allergies, according to the Infectious Diseases Society of America Foundation (IDSA).¹

Along with increased costs, patients with penicillin allergies are three times more likely to have adverse effects when hospitalized than those without allergies. Penicillin allergies can result in 10% more days hospitalized, compared to those without allergies, and a 30% increased risk for VRE infections. Patients with penicillin allergies are also 23% more likely to be infected with Clostridium difficile and 14% more likely to develop MRSA infections, according to the IDSA.¹

Inaccurate diagnoses of penicillin allergies can also result in antibiotic resistance that leads to the spread of superbugs. Patients who are allergic to penicillin may need to take stronger and more toxic antibiotics to treat a mild infection. These antibiotics are typically reserved for the treatment of difficult-to-treat infections such as MRSA and C difficile, and inappropriate use can lead to resistance, according to a study published by the BMJ.²

In this study, researchers concluded that patients with reported penicillin allergies received prescriptions for stronger antibiotics, including macrolide antibiotics, clindamycin, fluoroquinolones, tetracyclines, and sulfonamide antibiotics, more frequently than patients without a penicillin allergy. Patients receiving macrolide antibiotics, clindamycin, or fluoroquinolones, were found to be at an increased risk for MRSA and C difficile infections, while patients with a penicillin prescription were at an increased risk for MRSA.²

"Fluoroquinolones are some of the most commonly used antibiotics in hospitals, nursing homes and outpatient settings. Fluoroquinolones have broad-spectrum activity covering many common pathogens, favorable pharmacokinetics offering convenient dosing schedules, and are highly bioavailable orally. These characteristics have likely contributed to the overuse of this class of antibiotics," Lauri Hicks, DO, CDC told Pharmacy Times in an interview. Dr. Hicks, who is not involved with the study but addressed resistance issues during a press event relating to antibiotic resistance this week, is the director of the CDC's Office of Antibiotic Stewardship in the Division of Healthcare Quality Promotion at the National Center for Emerging and Zoonotic Infectious Diseases.

The study authors concluded that inaccurate penicillin allergy reporting, combined with overuse of some antibiotics, likely contributes to the growing problem of antibiotic resistance. Bringing awareness to the high rate of misreported penicillin allergies is an important part of identifying true allergies and eliminating inaccurate ones, in order to lower costs, reduce adverse effects, and prevent antibiotic resistance.²

References

• National Penicillin Allergy Day. Infectious Disease Society of America’s Website. Arlington, VA. https://www.idsafoundation.org/national-penicillin-allergy-day/ Accessed September 17, 2018.
• Blumenthal KG. Lu N. Zhang Y. Li Y. Walensky RP. Choi HK. Risk of Meticillin Resistant Staphylococcus aureus and Clostridium difficile in Patients with a Documented Penicillin Allergy: Population Based Cohort Study. BMJ 2018;361:k2400. June 27, 2018. https://www.bmj.com/content/361/bmj.k2400. Accessed September 17, 2018.