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# Tools > Vancomycin Calculator

Welcome to the Vancomycin Empiric Dosing Calculator. This calculator generates empiric doses for vancomycin using the Bugs & Drugs algorithm. This information does not supersede any clinical assessment and must be used in the clinical context of your patient.

To start, enter your patient data in the fields below; the information will automatically generate as you fill in the required fields.

Age: years
Sex:
Height:
Weight:
SCr: μmol/L
IBW:
DW: N/A
CrCl:

## Empiric Dosing

### Loading Dose

Include?
Dose/Weight: mg/kg
Dose:
Rounded Dose:

### Maintenance Dose

Trough Target:
Dose/Weight: mg/kg
Dose:
Rounded Dose:
Interval:
Draw Level:

### Pharmacokinetic Data

This data is for illustrative purposes only (e.g. to show the impact of loading doses, to visualize time to steady state). It makes multiple assumptions based on population pharmacokinetics that may or may not be applicable to your patient. These level estimations cannot be assumed accurate for your patient.

ke:
t1/2:
tSS:
Vd: 0.7 L/kg
Cmax:
Cmin:

## Equations & Calculations

Calculations used to generate above data. Due to rounding, some numbers may not add up exactly. Calculations are rounded at each step.

### Patient Weight Calculations

\begin{align} IBW\ (Male) & = 50\ kg + \left(\frac {0.92\ kg}{cm} * height\ over\ 150\ cm\right) &\\[10pt] IBW\ (Female) & = 45.5\ kg + \left(\frac {0.92\ kg}{in} * height\ over\ 150\ cm\right) & \end{align}

### Patient CrCl Calculations

\begin{align} CrCl\ (Male) & = \frac{\left(140 - age\right) * weight}{SCr} * 1.2 &\\[10pt] CrCl\ (Female) & = \frac{\left(140 - age\right) * weight}{SCr} & \end{align}

### Loading Dose Calculations

\begin{align} Loading\ Dose & = \frac{25\ mg}{kg} * actual\ body\ weight &\\ \end{align}

### Maintenance Dose Calculations

\begin{align} Maintenance Dose & = dose\ per\ weight * actual\ body\ weight &\\ \end{align}

### Empiric Interval Determination

Target Trough
Calculated CrCl 10-20 mg/L 15-20 mg/L
≥ 80 mL/min Q12H Q8H
40-80 mL/min Q24H Q12H
20-40 mL/min Q36H Q24H
10-20 mL/min Q48H Q48H
≤ 10 mL/min Consider loading dose and pharmacist consult

### Pharmacokinetic Calculations

\begin{align} k_e & = \left(0.00083 * CrCl\right) + 0.0044 &\\ \end{align}
\begin{align} t_{1/2} & = \frac{0.693}{k_e} &\\ \end{align}
\begin{align} t_{SS} & = t_{1/2} * 4\ or\ 5 &\\ \end{align}
\begin{align} V_{d} & = \frac{0.7\ L}{kg} * weight &\\ \end{align}
\begin{align} C_{max} & = \frac{Dose\ (mg)}{V_d\ (L) * \left(1 - e^{-ke * \tau}\right)} &\\ \end{align}
\begin{align} C_{min} & = C_{max} * e^{-ke * \tau} &\\ \end{align}

## Comments

• While we strive to ensure all aspects of this calculator are reliable and accurate, you must always use your clinical judgement when applying these calculations to a patient. We have provided the calculations used to allow you to verify that these numbers make sense in the context of your patient. Any additional pharmacokinetic and visual information is based on population pharmacokinetics and cannot be assumed accurate for your patient. This information is provided for illustrative purpose only.
• Time to steady state ranges from 4 to 5 half lives. This calculator shows you both options and, through rounding up, chooses when a trough should be drawn.
• Maintenance doses are capped at 2000 mg/dose. Higher doses may be used (if clinically appropriate) following trough monitoring.
• If you have any questions, concerns, or wish to report an error, please email us at studybuffalo@studybuffalo.com.

## References

Bauer LA. Applied Clinical Pharmacokinetics. 2nd ed. USA: McGraw-Hill Companies Inc.; 2008.

Blondel-Hill E, Fryters S. Bugs & Drugs. 2012.

Gray M, Fryters S, Dersch Mills D, Romanick, M. Vancomycin Pharmacokinetic Summary. 2012.