How is creatinine clearance estimated?

The tool uses the Cockcroft-Gault equation: CrCl = ((140 − age) × weight) ÷ (72 × serum creatinine in mg/dL), multiplied by 0.85 for females. If creatinine is entered in µmol/L it is divided by 88.4 to convert to mg/dL first.

What is the vancomycin AUC target?

The 2020 ASHP/IDSA guideline recommends AUC-guided dosing targeting an AUC/MIC ratio of 400–600 mg·h/L, assuming an MIC of 1 mg/L by broth microdilution. Trough-only monitoring is no longer the preferred approach for serious MRSA infections.

How are loading and maintenance doses chosen?

A loading dose of about 25 mg/kg (range 20–35) is used for serious infections, and maintenance is 15–20 mg/kg per dose. The interval is selected from renal function, lengthening as creatinine clearance falls.

How is the dosing interval picked?

As a rough guide: CrCl above 90 mL/min suggests every 8–12 hours, 50–90 every 12 hours, 20–49 every 24 hours, and below 20 every 24–48 hours dosed by levels. Confirm with measured pharmacokinetics.

Should I rely on this estimate alone?

No. This is a starting estimate only. Confirm and adjust dosing with two-level pharmacokinetic sampling or Bayesian software to hit the measured AUC, round doses to the nearest 250 mg, and cap single doses around 2–3 g.

Vancomycin Dosing & AUC/MIC Calculator

This calculator gives a starting vancomycin regimen based on the patient’s renal function, following the 2020 ASHP/IDSA move from trough-only monitoring to AUC-guided dosing for serious MRSA infections. It is built for infectious-disease pharmacists and physicians initiating therapy.

How it works

First it estimates renal function with the Cockcroft-Gault equation:

CrCl (mL/min) = ((140 − age) × weight) ÷ (72 × SCr) × (0.85 if female)

with serum creatinine (SCr) in mg/dL. If you enter creatinine in µmol/L it is divided by 88.4 to convert first. From the clearance it proposes:

Loading dose — about 25 mg/kg (guideline range 20–35) for serious infections, to reach therapeutic exposure quickly.
Maintenance dose — 15–20 mg/kg per dose.
Interval — chosen from renal function: faster clearance means more frequent dosing, slower clearance means longer intervals.

The AUC/MIC target

The guideline target is an AUC/MIC of 400–600 mg·h/L, conventionally assuming an MIC of 1 mg/L by broth microdilution. AUC-guided dosing reduces nephrotoxicity compared with chasing high troughs while maintaining efficacy.

Notes and safety

This tool produces a starting estimate only. Confirm and refine the regimen with two-level pharmacokinetic sampling or Bayesian dosing software to hit the measured AUC, especially in unstable renal function, obesity, or critical illness. In practice, round doses to the nearest 250 mg and cap single doses around 2–3 g. Monitor renal function throughout therapy. All calculation runs locally in your browser.