GLYCOPEPTIDE ANTIBIOTICS – VANCOMYCIN

Structure/Class
  1. Glycopeptide antibiotic
Pharmacodynamics
  1. Inhibits cell wall synthesis by binding to the D-ala—D-ala terminal of peptidoglycan (a portion of the bacterial cell wall) therefore preventing its elongation. This makes vancomycin useful in treating MRSA because MRSA changes its PBP binding site.
    • Effective only against G+ve bacteria.
    • Has synergistic effect with gentamicin and therefore can treat enterococcus effectively.
    • Can also cross the BBB.
    • Based on properties above, the indications are as follows:
      1. MRSA
      2. Treatment of penicillin-resistant pneumococcal meningitis (in combination with ceftriaxone, cefotaxime or rifampicin)
      3. Given orally to treat C.difficile.
Absorption/administration
  1. IV only as very poorly absorbed from GIT. PO used in very limited circumstances to treat C.difficile.
Distribution
  1. Crosses BBB
Metabolism
Excretion
  1. Mainly renally excreted (up to 90%). Will accumulate in renal failure.

 
Adverse events
  1. Common – present in 10% of cases but usually quite minor.
    • Phlebitis
    • Red man syndrome (due to histamine release)
    • Ototoxicity and nephrotoxicity (not common, but may have additive effect with gentamicin)