💊 Glycopeptides (Vancomycin)

Vancomycin is a glycopeptide antibiotic, a class of antimicrobials primarily used for serious Gram-positive bacterial infections, particularly those resistant to beta-lactams.

It inhibits bacterial cell wall synthesis by binding to the D-Ala-D-Ala terminus of peptidoglycan precursors. This prevents the transpeptidation and transglycosylation steps, leading to a defective cell wall and bacterial cell lysis.

Vancomycin is a crucial antibiotic for methicillin-resistant Staphylococcus aureus (MRSA) infections, including sepsis, endocarditis, and osteomyelitis. It is also used for severe Clostridioides difficile infection (CDI) orally, and in patients with serious Gram-positive infections who are allergic to penicillin.

Hypersensitivity to vancomycin is an absolute contraindication. Caution is required in patients with pre-existing renal impairment due to its nephrotoxic potential, and in those with hearing impairment due to ototoxicity.

Common adverse effects include 'red man syndrome' (flushing, rash, pruritus, hypotension) due to rapid infusion. Nephrotoxicity and ototoxicity are serious, dose-related adverse effects. Other effects can include myelosuppression (neutropenia, thrombocytopenia) and phlebitis at the injection site.

Therapeutic drug monitoring (TDM) of vancomycin trough levels is essential to ensure efficacy and minimise toxicity, particularly nephrotoxicity. Renal function (urea and electrolytes) should be closely monitored, along with full blood count, especially during prolonged therapy.

When prescribing, always check for penicillin allergy as vancomycin is a common alternative. Counsel patients on the potential for 'red man syndrome' if infused too quickly. Emphasise the importance of blood tests for monitoring kidney function and drug levels.

Vancomycin is a 'last-resort' antibiotic for many resistant Gram-positive infections. Oral vancomycin is only effective for C. difficile infection as it is poorly absorbed. Intravenous administration is required for systemic infections. Remember the 'red man syndrome' and its link to rapid infusion.

SBAs often test the indications for vancomycin, particularly MRSA infections or severe C. difficile. Questions may also focus on its key adverse effects like 'red man syndrome' or nephrotoxicity, and the importance of therapeutic drug monitoring.