Vancomycin Trough Level

Vancomycin Dosing & Monitoring

Non-Dialysis Patients

  • Standard 15–20 mg/kg/dose
  • Round weight to nearest 250 mg
  • Frequency every 8–12 hours (every 8 hrs if rapid renal clearance e.g., burns, young patients)
  • Maximum single dose DO NOT exceed 2000 mg unless troughs are below target

Vancomycin – Adverse Effects

Infusion Reactions
  • Phlebitis: Associated with vancomycin’s acidic pH. Risk can be reduced by:
    • Using central venous access
    • Slowing the infusion rate
    • Increasing dilution volume
    • Using continuous infusion when needed
  • Rash (Histamine-mediated, formerly “Red Man Syndrome”):
    • Presents with erythema affecting head, neck, trunk, extremities, or generalized urticaria
    • Prevention:
      • Infuse at ≤500 mg/hour
      • Premedicate with antihistamines if needed
      • Slow infusion rate or consider continuous infusion in some cases
Acute Kidney Injury
  • Mechanism: Nephrotoxicity due to apoptosis of proximal tubular epithelial cells from drug accumulation
  • Risk Factors:
    • High doses
    • Increased body weight
    • Pre-existing renal impairment
    • Critical illness
    • Concurrent nephrotoxins:
      • Aminoglycosides
      • Loop diuretics
      • Amphotericin B
      • IV contrast dye
      • Vasopressors
  • Incidence:
    • Varies from 5–43% depending on the study
    • Meta-analysis (15 studies): AKI risk 2.45x higher with vancomycin vs non-glycopeptides
    • Most cases develop between 4–17 days after starting therapy

Trough Monitoring

  • Draw trough 30 mins before 4th dose + for extended intervals (>24 hrs) before 3rd dose
  • NEVER draw from same IV line as Vanco (falsely high levels)
  • Do NOT withhold doses while awaiting levels unless
    • Renal impairment
    • Suspected toxicity
Infection TypeTarget Trough
Standard10–15 mcg/mL
Deep-seated -> endocarditis, bacteremia, osteomyelitis, severe pneumonia15–20 mcg/mL

Low Trough Level

Possible Causes

  • Sample drawn too late
  • Missed doses

Management

  • Confirm proper dosing and sample timing
  • If renal function stable → Increase dose
  • Recheck level before 3rd or 4th dose

Therapeutic Trough Level

Management

  • Continue current dosing
  • Recheck troughs periodically

High Trough Level

Possible Causes

  • Sample drawn too early
  • Sample drawn from Vancomycin IV site

Management

  • Confirm dose and timing
  • If sample error → repeat at correct time
  • If renal function stable →
    • Omit one dose, then
    • Increase interval or reduce dose

If level is very high or renal function is worsening

  • Stop Vancomycin
  • Resume only when levels normalize
  • Consult Microbiology before restarting

Monitoring & Escalation

  • Check RFTs every 48–72 hours (or daily if unstable)
  • Call for help if
MOC