Paper II — 2022 October (Supplementary) (2010 Scheme) — Q6
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Paper II
2022 October (Supplementary) (2010 Scheme)
Question
Vancomycin
Q63 marksShort Notes
Answer
Vancomycin is the prototype glycopeptide antibiotic.
MOA: vancomycin → binds the D-alanyl-D-alanine terminus of the peptidoglycan precursor → sterically blocks transglycosylation/transpeptidation → inhibits bacterial cell wall synthesis. A fundamentally different binding mode from beta-lactams (binds the substrate, not the PBP enzyme), which is why it retains activity against many beta-lactamase-producing and PBP-altered organisms.
Uses: MRSA (methicillin-resistant Staphylococcus aureus) infections, severe Gram-positive infections in penicillin-allergic patients, oral vancomycin for C. difficile colitis (poor oral absorption gives a local gut effect).
Adverse effects: nephrotoxicity and ototoxicity (requiring plasma level monitoring, worse with concurrent aminoglycoside use), “red man syndrome” (a non-allergic, histamine-release-mediated flushing/hypotension reaction related to rapid infusion rate — managed by slowing the infusion, not treated as a true allergy).
