Penicillin allergy is reported to affect 11% of inpatients1. We have investigated the clinical and incident report outcomes where penicillin has been given to a patient who has previously reported a penicillin allergy.
 
Methods
We performed a search of the Trust’s incident reporting database using the terms “medication error” with “infections” between 24th March 2011-15. We excluded reports concerning non-penicillin antibiotics. Incident forms and patient notes were reviewed to establish precipitating events and clinical outcome. Patient harm was classified using the National Patient Safety Agency grading of incidents2.

Results and Discussion
Sixty-nine incident reports were identified (inpatient wards 23, A&E 16, theatres 12, paediatric unit 7, maternity 2, critical care 1). The patient received the drug in 57 cases (83%). No harm was experienced in 52 cases (91%). Mild and moderate harm were experienced in 4 (7%) and 1 (2%) of cases respectively with no occasions of severe harm or death.  Patients experiencing mild harm all developed a rash.  One patient reported tingling of the tongue and lips. One patient developed anaphylaxis and cardiac arrest and was successfully resuscitated with no sequelae. Analysis of events suggested most common risk factors were prescriptions within A&E, patients with confusion or decreased GCS, patient delayed allergy reporting, delay to obtaining previous notes and changes to antibiotics following bacterial sensitivities. Following the incident, patients commonly had their antibiotic changed however there was no clinical follow-up relating to the allergy.  

Adverse clinical outcomes following the inadvertent administration of penicillin is rare, likely due to few patients being truly allergic previously estimated as less than 2%1. Penicillin allergy has been associated with increased total hospital days, increased incidence of resistant organisms including MRSA, C. difficile and VRE and cost to healthcare through use of alternative agents. Incident follow-up focuses on the error without the need to investigate the allergy diagnosis.  

Conclusion
Referral to an allergy service may suggest a patient can be given penicillin safely and allow more appropriate first-line antibiotic choices. Despite this requiring expanded allergy services, healthcare cost savings have been previously demonstrated1.  

References
1Macy E and Ngor E. Safely diagnosing clinical significant penicillin allergy using only penicilloyl-poly-lycine, penicillin and oral amoxicillin. The Journal of Allergy and Clinical Immunology: In practice 2013; 1(3): 258-263

2National Patient Safety Agency.  Seven steps to patient safety.  The full reference guide.  July 2004 pp 100

Outcomes associated with the inadvertent administration of penicillin to patients previously reporting an allergy