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Peak And Trough Levels Calculator

Work out peak and trough levels instantly with clear inputs, formula shown and shareable results.

About Peak And Trough Levels Calculator

Applies the one-compartment multiple-dose equations to predict steady-state peak and trough concentrations for a given dose and interval.

Formula

Multiple-dose peak and trough

ke = ln2 / half-life; Cmax = (dose / Vd) / (1 - e^-ke.tau); Cmin = Cmax x e^-ke.tau; accumulation factor = 1 / (1 - e^-ke.tau)

Worked example

With the default values below, Peak And Trough Levels Calculator returns Steady-state peak of 30.938. Change any input above and every figure here is recalculated in your browser.

Inputs used

Doseaccepts 1–10,000 mg
1,000 mg
Volume of distributionaccepts 1–500 L
50 L
Half-lifeaccepts 0.2–200 h
8 h
Dosing intervalaccepts 1–72 h
12 h

Results

Steady-state peak
30.938 mg/L
Steady-state trough
10.938 mg/L
Peak to trough ratio
2.83
Accumulation factor
1.547

Step by step

  1. 1Values used
  2. 2Multiple-dose peak and trough
  3. 3Steady-state peak= 30.938 mg/L
  4. 4Steady-state trough= 10.938 mg/L
  5. 5Peak to trough ratio= 2.83
  6. 6Accumulation factor= 1.547

Assumptions and limits

  • The result is derived only from the 4 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 3 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

When should a trough be sampled?

Immediately before the next dose, once steady state has been reached.

Why is the peak not sampled straight after an infusion?

Distribution is still occurring; peaks are usually drawn one to two hours after the infusion ends.

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