Vancomycin

Vancomycin: Overview

Vancomycin is a glycopeptide antibiotic primarily used for treating serious Gram-positive infections. The intravenous (IV) and oral (PO) forms of Vancomycin have distinct uses and indications.

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1. Vancomycin IV (Intravenous)

• Spectrum:
  • Gram-positive: Broad coverage against MSSA, MRSA, Streptococcus, Enterococcus faecalis (not VRE)
  • Gram-negative: No coverage
  • Anaerobes: No anaerobic coverage except for Gram-positive anaerobes in blood
• Key Notes:
  • First-line for MRSA infections, including bacteremia, endocarditis, pneumonia, and osteomyelitis.
  • Requires therapeutic drug monitoring (trough levels) to avoid nephrotoxicity and less commonly ototoxicity.
  • No systemic Gram-negative or anaerobic coverage, so often combined with other antibiotics (e.g., Zosyn or Cefepime) for broad-spectrum coverage in mixed infections.
  • Used for serious infections where other antibiotics may not be effective, particularly in patients with beta-lactam allergies.

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2. Vancomycin PO (Oral)

• Spectrum:
  • Gram-positive: No systemic absorption, only effective in the GI tract
  • Gram-negative: No coverage
  • Anaerobes: Effective against Clostridioides difficile in the gut
• Key Notes:
  • Not absorbed systemically: PO Vancomycin only works within the gastrointestinal tract.
  • 2nd-line for treating Clostridioides difficile infection (C. diff) 
  • Not effective for systemic infections, as it stays localized in the intestines.
  • Dosage adjustments for renal impairment are not necessary since it is not absorbed into the bloodstream.

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Summary

• Vancomycin IV: Primarily used for serious Gram-positive infections like MRSA, endocarditis, and bacteremia. Requires therapeutic monitoring to avoid toxicity.
• Vancomycin PO: Used exclusively for C. difficile infections in the GI tract, with no systemic absorption or effect on other infections.