Warning
  • Penicillins (and all beta lactams) should be avoided in those who have a true allergy (anaphylaxis) - this occurs in under 1% of patients
  • Penicillin allergy is documented in over 10% of patients but the nature of allergy is often uncertain (not a true allergy)
  • Cross sensitivity between penicillins and 1st/2nd generation cephalosporins has been reported in up to 10% and for 3rd generation cephalosporins 2-3% of patients
  • Cephalosporins should be avoided in those who have a true penicillin allergy (anaphylaxis)
  • Cephalosporins may be used with caution in patients with mild sensitivity to penicillin (e.g. develop a rash) 
  • Confirm the nature of a drug allergy with the patient as it is often not a true allergy

Editorial Information

Last reviewed: 31/07/2024

Next review date: 31/07/2027

Version: V1.0

Approved By: AMT (23.07.24) and ADTC (31.07.24)

Reviewer name(s): Jon van Aartsen (consultant microbiologist), Claire Mitchell (pharmacist).