PTCB Certified Pharmacy Technician (PTCE)MedicationsHard
A pharmacy technician is performing a final check on a prescription for 'cephalexin 250 mg, take 1 capsule by mouth every 6 hours' for a patient with a documented penicillin allergy. What is the MOST appropriate action for the technician to take?
- AMark the prescription with an auxiliary label 'May cause drowsiness'.
- BAdvise the patient to take the medication with food to prevent an allergic reaction.
- CAlert the pharmacist immediately due to potential cross-reactivity.
- DDispense the medication as prescribed, as cephalexin is not a penicillin.
Show answer & explanationAnswer & explanation
Correct answer: C. Alert the pharmacist immediately due to potential cross-reactivity.
Cephalexin is a first-generation cephalosporin, and there is a known, albeit low, risk of cross-reactivity between penicillins and first/second-generation cephalosporins. Given the patient's documented penicillin allergy, the technician must alert the pharmacist to assess the risk and determine if an alternative antibiotic is needed or if the benefit outweighs the risk.
Why the other options are wrong
- A. Drowsiness is not a primary concern with cephalexin, and this action does not address the allergy issue.
- B. Taking with food may mitigate GI upset but will not prevent an allergic reaction.
- D. While cephalexin is not a penicillin, the risk of cross-reactivity means it should not be dispensed without pharmacist review.
Penicillin-Cephalosporin Cross-Reactivity
The potential for an allergic reaction in a patient with a penicillin allergy when exposed to a cephalosporin antibiotic, due to structural similarities (beta-lactam ring).
- Risk is highest with first-generation cephalosporins (e.g., cephalexin) and lowest with third/fourth-generation.
- The overall risk is generally low (around 1-10%), but can be serious.
- Always requires careful assessment by a pharmacist or prescriber.
Memory trick: For 'Beta-Lactam' allergies, 'Cross-Check' carefully to 'Avoid Reaction'.