Vancomycin

Key points

• Vancomycin is a glycopeptide antibiotic used in the treatment of Gram positive infections, particularly methicillin-resistant Staphylococcus aureus (MRSA). Mechanism of action
• inhibits cell wall formation by binding to D-Ala-D-Ala moieties, preventing polymerization of peptidoglycans Mechanism of resistance
• alteration to the terminal amino acid residues of the NAM/NAG-peptide subunits (normally D-alanyl-D-alanine) to which the antibiotic binds Adverse effects
• nephrotoxicity
• thrombophlebitis
• MONITORING: vancomycin has a narrow therapeutic index and requires THERAPEUTIC DRUG MONITORING — pre-dose (trough) levels are checked, with a HIGHER target (around 15–20 mg/L) for deep-seated or CNS infection such as brain abscess, MRSA bacteraemia or endocarditis · monitor renal function, since nephrotoxicity is dose- and level-related and risk rises with concurrent aminoglycosides or other nephrotoxins.
• OTHER EFFECTS: ototoxicity · 'red man syndrome' — an infusion-rate-related HISTAMINE release reaction with flushing of the upper body, NOT an IgE-mediated allergy, so it is managed by slowing the infusion rather than by labelling the patient allergic. This distinction is a classic exam trap.