Monitoring

Baseline
Once weekly (more frequently if renal function changing or if concurrent nephrotoxic drugs)
If creatinine changes (increase in Scr of ≥ 40 µmol/L, or 50% of baseline), draw vancomycin trough level to assess need for dosing change

Order only if patient meets inclusion criteria.
Draw levels during daytime hours; no need to do in evening/overnight. Avoid weekend levels if possible.
Vancomycin trough levels should be deferred until after culture & susceptibility results are available and it is confirmed that ongoing vancomycin therapy is needed. Early vancomycin target concentrations can be achieved with weight & renal function based dosing (see vancomycin dosing) and risk of toxicity is low with maximum of 2-3 days of empiric vancomycin therapy.
Collect serum specimen 30 minutes or less before next dose

Pediatrics:

first level at steady state - pre 5th dose is recommended if normal renal function; pre-3rd can be used in neonates, patients with GFR < 80mL/min/1.73m², and/or on concomitant nephrotoxins, or in patients considered at high risk of acute renal failure
subsequent levels every 5-7 days

Adults:

first level at steady state (see Vanco SS calculator) and after at least 2 maintenance doses (~ 30 hours if normal renal function, e.g. prior to 4th dose if q12h or prior to 5th dose if q8h)
vancomycin clearance is enhanced in obesity. For morbidly obese patients (≥ 190% IBW or BMI ≥ 40kg/m²) consider drawing first level sooner (e.g. before 2^nd or 3^rd dose)
subsequent levels every 7-10 days (may need more frequently if renal function changing or concurrent nephrotoxic drugs)

Intermittent hemodialysis (IHD) with high flux filters:

Draw serum vancomycin level before 3rd maintenance dose (draw prior to/at the start of dialysis run). Subsequently, draw levels weekly for the duration of therapy. Additional levels may be ordered as clinically indicated.

Recent US guidelines have recommended AUC (or AUC:MIC assuming MIC =1) monitoring. In AHS, this method of monitoring is strongly discouraged because:
- of the need for more levels, more calculations and/or use of expensive Bayesian prediction software programs.
- the evidence supporting AUC/MIC monitoring is generally retrospective and of low quality.
Numerous clinical studies have found high correlation between AUC and trough, therefore the use of the easier to use trough level method of monitoring continues to be recommended in AHS