Repeated-input peak and trough envelope with average-exposure railLive current inputs
Health & Fitness
Medication Interval Dose Planning Calculator
Audit the theoretical peak, trough, average exposure, and fluctuation of an already prescribed regimen under a one-compartment first-order model without generating or recommending a dose.
Model-derived half-life—
Theoretical steady-state average—
Idealized post-event peak—
Idealized pre-event trough—
Peak-to-trough ratio—
Exposure per interval—
Accumulation factor—
Clinical boundary—
PRESCRIBED-REGIMEN AUDIT
Repeated-input peak and trough envelope with average-exposure rail
A sawtooth concentration index shows idealized accumulation over the entered cycles; the area rail keeps AUC and average exposure distinct from instantaneous peaks.
CYCLE LEDGER
Modeled peak, trough, and interval exposure by cycle
The table exposes the approach to the theoretical plateau rather than displaying only a final ratio.
| Cycle | Pre-event amount index | Post-event amount index | Interval AUC index | Fraction of plateau | Audit note |
|---|
AUDIT SETUP
Do not solve backward for a new dose
- Enter only a regimen that has already been prescribed.
- Use clearance and volume from an appropriate medicine-specific source.
- Confirm the formulation is compatible with instantaneous-input assumptions.
- Read peak, trough, and average as theoretical indices.
- Take questions to the prescribing clinician or pharmacist.
EXPOSURE GEOMETRY
The same average can hide very different fluctuation
Average steady-state exposure is driven by dose rate and clearance. Peak-to-trough fluctuation also depends on interval and half-life.
Real absorption, protein binding, active metabolites, multi-compartment behavior, nonlinear clearance, and therapeutic drug monitoring can make these indices clinically misleading.
ONE-COMPARTMENT AUDIT
Calculate exposure from an entered regimen, never a recommended regimen
Clearance and distribution volume imply an elimination constant. The entered dose and bioavailability create an input amount; the prescribed interval determines accumulation and fluctuation.
Detailed calculation process and general formulas
k = CL / Vt_half = ln(2) / kAUC_tau = F x Dose / CLC_avg,ss = F x Dose / (CL x tau)C_max,ss = (F x Dose / V) / (1 - exp(-k x tau))C_min,ss = C_max,ss x exp(-k x tau)Symbols, meanings, and units
- CL
- entered reference clearanceL/hour
- V
- entered reference distribution volumeL
- F
- entered bioavailability fractiondimensionless
- Dose
- already prescribed amountentered amount units
- C
- idealized concentration indexamount units/L
AUDIT QUESTIONS
Three results that must not be collapsed
The model reports average, fluctuation, and total interval exposure separately.
Average exposure
—Dose rate divided by clearance creates the theoretical mean.
Fluctuation
—The interval-to-half-life ratio controls idealized peak-to-trough spread.
Interval exposure
—AUC keeps total exposure separate from timing within the interval.
Decision takeaway: Use the audit to understand terminology in a medicine discussion, not to calculate a personal prescription.
Applied decisions
Why dose rate alone does not describe the regimen
Long half-life relative to interval
The elimination constant is small and repeated inputs overlap substantially.
What the result clarifies: The chart shows higher accumulation with a narrower relative fluctuation.
Short half-life relative to interval
Most of the modeled amount leaves before the next event.
What the result clarifies: The same dose rate can produce a wider peak-to-trough pattern.
Worked default scenario
Current-input substitution and reconciliation
Method references
Evidence used to frame this specific model
Scope and limitations
Educational PK audit only. It is not a dosing calculator for clinical use and must not be used to choose, change, split, skip, repeat, or stop a medication. Actual dosing requires medicine-specific prescribing information and professional judgment.
Medication Interval Dose Planning Calculator | Prescribed-Regimen PK Audit FAQ
Can I enter a target concentration and solve for dose?
No. This page intentionally audits only an already prescribed regimen.
Why is the peak called idealized?
The model assumes immediate distribution in one compartment and omits absorption kinetics.
Are the concentration units clinically valid?
Only when the entered dose, clearance, volume, and bioavailability use compatible medicine-specific units.
Does a lower fluctuation mean safer?
Not necessarily. Safety depends on the medicine, patient, exposure-response relationship, and monitoring.