A pharmacy technician is preparing a compounded sterile product (CSP) for a patient with a known penicillin allergy. The order is for 'cefazolin 1 gram IV every 8 hours'. What is the most appropriate action for the technician?
- APrepare the CSP as ordered, as cefazolin is not a penicillin.
- BNotify the nurse that the patient needs a penicillin allergy band.
- CAlert the pharmacist immediately due to potential cross-reactivity.
- DCheck the patient's medical history for other drug allergies.
Show answer & explanationAnswer & explanation
Correct answer: C. Alert the pharmacist immediately due to potential cross-reactivity.
Cefazolin is a first-generation cephalosporin, which has a known potential for cross-reactivity with penicillin in patients with a penicillin allergy. While the risk is relatively low (historically cited as 5-10%, now thought to be <1% for some newer cephalosporins), it is a serious enough concern to warrant immediate pharmacist intervention to assess the allergy type (e.g., rash vs. anaphylaxis) and determine if an alternative medication is safer.
Why the other options are wrong
- A. This is incorrect. Cefazolin, a cephalosporin, shares a similar beta-lactam structure with penicillin, leading to a risk of cross-reactivity.
- B. Notifying the nurse about an allergy band is not the technician's role and does not address the immediate drug-allergy interaction concern.
- D. While checking the patient's full allergy history is good practice, the immediate concern is the known penicillin allergy and potential cross-reactivity with the ordered cephalosporin, requiring pharmacist assessment.
Penicillin-Cephalosporin Cross-Reactivity
The potential for an allergic reaction to a cephalosporin in a patient with a known penicillin allergy, due to structural similarities (beta-lactam ring) between the two antibiotic classes.
- Risk is greatest with first-generation cephalosporins (e.g., cefazolin).
- Risk is lower with second- and third-generation cephalosporins.
- Requires careful assessment by a pharmacist/prescriber, especially for severe penicillin allergies.
Memory trick: Allergies are warnings, always stop and assess.