
In this lecture from This is Why, Dr. Busti will answer the question, "Are patients with a penicillin allergy really at high risk when we use cephalosporins?" Dr. Busti will also discuss some of the evidence on penicillin allergy & cephalosporin cross-reactivity and shows you how to safely use β-lactam antibiotics in clinical practice.
In this episode, we’ll cover:
- Why most penicillin allergy labels are incorrect
- The true risk of cephalosporin cross-reactivity (and why it’s not what you think)
- How R1 side chains drive cross-reactivity between β-lactam antibiotics
- Practical, step-by-step approaches to antibiotic allergy risk stratification
The goal = make medical education easy and clinically relevant.
Chapter Table of Contents
0:00 Penicillin Allergy and Cephalosporins: Real Cross-Reactivity Risk
1:26 Penicillin–Cephalosporin Cross-Reactivity: Myths vs Evidence
1:54 True Cross-Reactivity Risk Is Only 1–2 Percent
3:07 When Cephalosporin Cross-Reactivity Risk Is Higher
4:17 R1 Side Chains Explain Beta-Lactam Cross-Reactivity
6:08 Why Amoxicillin and Aminopenicillins Increase Risk
8:10 Aminocephalosporins to Avoid in True Penicillin Allergy
10:51 Clinical Takeaways for Safe Beta-Lactam Use
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#penicillinallergy #cephalosporincrossreactivity #cephalosporinsinpenicillinallergy #betalactamallergy #drbusti
Disclaimer:
This content is for educational purposes only and is not medical advice. It does not replace individualized evaluation, diagnosis, or treatment. Always seek the advice of a qualified health provider with questions about a medical condition and never delay care because of educational content.

Penicillin Allergy & Cephalosporin Cross-Reactivity Images
Penicillin Allergy & Cephalosporin Cross-Reactivity Images