ceftazidime

Allergy cross-reactivity

• Class-level overall cross-reactivity (penicillin ↔ cephalosporin)

  Risk level: Low

  Basis: Class-wide (non-R1-matched pairs) — context group

  Other active ingredients in the same group:

  • amoxicillin
  • ampicillin
  • aztreonam
  • benzylpenicillin
  • cefadroxil
  • cefalexin
  • cefazolin
  • cefepime
  • cefixime
  • cefotaxime
  • ceftriaxone
  • cefuroxime
  • flucloxacillin
  • piperacillin

  Notes: Class-level overall cross-reactivity between penicillins and cephalosporins is LOW in modern data (~1-2%). The R1 side chain is the true determinant. Consult a specialist.

  Source: https://www.ncbi.nlm.nih.gov/books/NBK459320/

• Ceftazidime ↔ Aztreonam (identical R1)

  Risk level: Moderate

  Basis: Identical R1 side chain

  Other active ingredients in the same group:

  • aztreonam

  Notes: Ceftazidime has a side chain identical to aztreonam and clinical cross-reactivity has been demonstrated in vitro. Consult a specialist.

  Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC1291320/

• Oximino cephalosporins (similar aminothiazole-methoxyimino R1)

  Risk level: Moderate

  Basis: Similar/identical aminothiazole-methoxyimino R1 side chain

  Other active ingredients in the same group:

  • cefepimeSubgroup: core
  • cefotaximeSubgroup: core
  • ceftriaxoneSubgroup: core
  • cefuroximeSubgroup: related

  Notes: Cefotaxime, ceftriaxone, cefepime and cefuroxime carry a similar (mostly identical) R1 side chain; ceftazidime differs slightly. The more cautious MODERATE tier is chosen for safety. Consult a specialist.

  Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC4509666/

Cross-reactivity risk is not definitive; consult an allergy/infectious disease specialist.