Renal Dose Adjustment Calculator

Work out renal dose adjustment instantly with clear inputs, formula shown and shareable results.

About Renal Dose Adjustment Calculator

Applies the conventional renal impairment dose bands, showing both the dose-reduction and interval-extension routes to the same reduced daily exposure.

Formula

Renal adjustment bands

CrCl 50 or more: no change; 30-49: 75% of dose or 1.5 times the interval; 10-29: 50% or double the interval; under 10: 25% or triple the interval

Worked example

With the default values below, Renal Dose Adjustment Calculator returns Dose-reduction option of 375.0. Change any input above and every figure here is recalculated in your browser.

Inputs used

Normal doseaccepts 0.1–10,000 mg: 500 mg
Normal intervalaccepts 1–72 h: 8 h
Creatinine clearanceaccepts 1–200 mL/min: 30 mL/min

Results

Dose-reduction option: 375.0 mg
Interval-extension option: 12.0 h
Dose factor applied: 0.75
Daily dose with both applied: 750.0 mg

Step by step

1Values used
2Renal adjustment bands
3Dose-reduction option= 375.0 mg
4Interval-extension option= 12.0 h
5Dose factor applied= 0.75
6Daily dose with both applied= 750.0 mg

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

Frequently Asked Questions

Reduce the dose or extend the interval?

Extend the interval for concentration-dependent drugs such as aminoglycosides; reduce the dose for time-dependent drugs where troughs matter.

Do these bands replace the product literature?

No. Drug-specific renal dosing tables always take precedence over generic bands.