Patient is allergic to Beta-lactamase and which of following drug is safe to administer?

Appeared in: AIIMS Delhi NO- 2019

Explanation

Vancomycin is a glycopeptide antibiotic, which is structurally different from beta-lactam antibiotics.
It does not contain the beta-lactam ring that is responsible for allergic reactions in susceptible individuals.
Therefore, it is considered a safe and common alternative for treating infections in patients with a documented allergy to beta-lactam drugs like penicillin.

Option A: Amoxicillin is an aminopenicillin, which is a type of beta-lactam antibiotic. It is contraindicated in patients with a known beta-lactam allergy.
Option B: Penicillin is the original beta-lactam antibiotic. Administering it to a patient with a known allergy to this class would likely cause a severe allergic reaction.
Option D: Cefazoline is a first-generation cephalosporin. Cephalosporins are also beta-lactam antibiotics and have a known risk of cross-reactivity with penicillins.

Clinical Relevance

Nursing practice connection: Use the key finding related to Antibiotic Classes and Drug Allergies to guide bedside assessment, documentation, and the next nursing action.
Verifying patient allergies before administering any medication is a fundamental and critical nursing responsibility to ensure patient safety.
Understanding antibiotic classes and the potential for cross-reactivity is essential for safe medication administration. An allergy to one beta-lactam (e.g., penicillin) should be considered a potential allergy to all others (e.g., cephalosporins).
What if? If a patient reported only a mild, non-itchy rash to amoxicillin years ago, a physician might cautiously consider a third-generation cephalosporin. However, for a history of severe reaction (like anaphylaxis) or an unknown reaction type, all beta-lactams must be avoided, and a non-beta-lactam like vancomycin is the safer choice.

How to Approach the Question

First, identify the core of the question: finding a safe antibiotic for a patient with a beta-lactam allergy.
Recognize that 'Beta-lactamase allergy' is a common misstatement for 'beta-lactam antibiotic allergy'. The allergy is to the drug's chemical structure, not a bacterial enzyme.
Categorize each drug option by its antibiotic class.
Identify Amoxicillin and Penicillin as penicillins, and Cefazoline as a cephalosporin. All three are beta-lactam antibiotics.
Identify Vancomycin as belonging to a different class (glycopeptide).
Conclude that the drug from the different structural class (Vancomycin) is the only safe option to avoid an allergic reaction.

Concept Tested & Keywords

Concept Tested: Antibiotic Classes and Drug Allergies
Stem keywords: allergic, Beta-lactamase, safe to administer
Lead-in keywords: which of following
Clinical cues: Patient allergy to a class of drugs is a critical safety consideration.

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E6 Medicine Davidson Principles Practice 24e p. 140-142

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 1471-1473

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