A 55-year-old with a history of anaphylaxis to penicillin requires treatment for Enterococcus faecalis endocarditis. Which antibiotic should be avoided due to risk of cross-reactivity?
- A Ceftriaxone ✓
- B Vancomycin
- C Aztreonam
- D Daptomycin
Correct answer: A. Ceftriaxone
Explanation
Ceftriaxone, a third-generation cephalosporin, shares a beta-lactam ring and may cross-react in patients with severe penicillin allergy. Aztreonam, a monobactam, does not cross-react with penicillin. Vancomycin and daptomycin are non-beta-lactam cell wall inhibitors and are safe. Avoiding cephalosporins in anaphylaxis is standard practice.
Reference: Katzung: Basic & Clinical Pharmacology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.