Ask Your Pharmacist

February 27, 2020

My mother told me I am allergic to penicillin. Is having a penicillin allergy a problem for me in an era of antibiotic resistance?


Thanks for your question! This is a topic that is near and dear to my heart.

What is antibiotic resistance?

Antibiotic resistance happens when bacteria change in response to being exposed to antibiotics. This may cause antibiotics to become ineffective and infections to persist in the body, making it hard for us to get better when we are sick with a bacterial infection. Bacteria learn new ways, or resistance mechanisms, to make antibiotics not work. This is a global problem that threatens our ability to treat common infectious diseases, resulting in prolonged illness, disability, and death. Without effective antibiotics for prevention and treatment of infections, medical procedures such as organ transplantation, cancer chemotherapy, diabetes management and major surgery (for example, caesarean sections or hip replacements) become very high risk.

What is antimicrobial stewardship?

Antimicrobial stewardship means using antibiotics when they are needed and only when they are needed. Antibiotics are being over-used. Over 90 per cent of antibiotics dispensed for human use are prescribed in community health settings and the main prescribers are family physicians, dentists, pharmacists, and nurse practitioners. 

According to Dr Jerome Leis and his colleagues at Sunnybrook Health Sciences Centre (Toronto, ON), between 30 and 50 per cent of antibiotics prescribed for respiratory infections are unnecessary (i.e. antibiotics do not work against viruses). This proportion accounts for half of all antibiotics prescribed in family practice settings.

How can you do your part to minimize antibiotic resistance?

Be conscious of your expectations about being prescribed antibiotics for yourself and your children. When we have signs and symptoms of a cold, flu, or seasonal allergies, it can be hard to tell what exactly is going on. We know we feel miserable and we just want to feel better.  Talk to your doctor or nurse practitioner about what your symptoms are all about before asking for an antibiotic. Sometimes, it is unclear whether your signs and symptoms require antibiotics.   In these cases, you may be given an antibiotic prescription to have on hand in case your condition worsens. Using this type of delayed prescription has been shown to decrease antibiotic use by 55 per cent.  

Make sure you have accurate and up-to-date information regarding antibiotic allergies. For example, you may have been told by a parent that you have a penicillin allergy based on a childhood reaction but really don’t know much more than that about your allergy history.    Being labelled with a penicillin allergy limits many effective antibiotic treatment options for common infections in the community. It may be difficult to find an effective treatment if your doctor or nurse practitioner believes your penicillin allergy is real. The unintended consequence of an incomplete allergy history may be that you receive a stronger antibiotic than needed.  Exposing bacteria to stronger antibiotics allows them the opportunity to learn how to become resistant to these stronger medicines. The cycle continues and we are left with fewer and fewer options to treat infections.

It is important to clarify the nature of your antibiotic allergies (especially to penicillin) in advance of needing antibiotics. Your family practitioner can refer you to an allergist for skin testing and further investigation into the nature of your allergy. Remember that an upset stomach or diarrhea, although unpleasant, is an antibiotic intolerance and not an allergy.

Some questions I ask patients to help me clarify the likelihood of a serious antibiotic allergy include:

Who told you about your allergy? Did the reaction occur more or less than 10 years ago?  What happened when you consumed the medication? When did your signs and symptoms occur in relation to the timing of your antibiotic?  Did you have to go to the hospital to receive treatment for your allergic reaction?  Have you had the antibiotic since, and if so, what happened?   

Talk to your pharmacist on your next visit to the pharmacy to make sure your allergy history is up to date.     

Dr Kevin Duplisea (PharmD BSc. Pharm, BSc. ACPR) is a pharmacist at Sharp’s Corner Drugstore in Sussex, New Brunswick. His opinions expressed in this newspaper are published for educational and informational purposes only, and are not intended as a diagnosis, treatment or as a substitute for professional medical advice, diagnosis or treatment. Send your questions to