For educators

MaatiRx for pharmacokinetics courses

MaatiRx was called DoseCurve until October 2026. Links you have already shared keep working.

A free, open-source simulator for teaching pharmacokinetics and PK/PD. It runs in the browser with no accounts and nothing to install: students change a drug, a patient or a regimen and watch the curves respond, then predict, explain and practise.

Educational model, not for clinical dosing.

Open the simulatorLessonsCasesRun a class

What it covers

• One- and two-compartment models; oral, IV bolus and infusion dosing; regular regimens with loading and missed doses, and custom schedules.
• A clinical patient: Cockcroft–Gault creatinine clearance (actual, ideal or adjusted weight) and renal dose adjustment; saturable (Michaelis–Menten) elimination; the well-stirred liver model.
• PK/PD: the sigmoid Emax model, an effect-site delay, and the four basic indirect response models.
• Antimicrobials: fT>MIC on the unbound level, Cmax/MIC and AUC24/MIC, with a numeric target only where a cited source gives one.
• Levels: Bayesian (MAP) individualization from measured levels, and hemodialysis sessions.
• Population variability with probability of target attainment, and a sensitivity analysis that shows which input matters most.
• A drug library of 12 teaching profiles, each value naming its source (an FDA label or a paper) or marked unverified.

Run a class in ten minutes

1. Pick the material. A lesson or a case below, or a worksheet from the Practice tab (a topic and 5, 10 or 15 problems). Every one has its own link.
2. Write a case of your own (optional). Under Cases → For instructors, describe a patient, choose a drug and the regimens students may pick, and set a target (a peak and trough, an AUC24, or a time above the MIC). MaatiRx checks every regimen your choices allow before it makes the link.
3. Make an assignment. Put up to 12 cases and worksheets in one link and post it.
4. Collect completion codes. Choose a class key and give each student an identifier that isn't their name. At the end they get a code you can verify with the same key. Nothing is sent anywhere: progress and answers stay in each student's browser.

The teaching guide has a week-by-week plan for a pharmacokinetics course and what the model includes and leaves out.

Lessons

Each link opens the lesson with its scenario, its baseline and its challenge.

PK fundamentals

• Oral vs IV bolus Absorption delay, Tmax, Cmax and bioavailability.
• Reduced clearance Longer half-life, more exposure, more accumulation.
• Kidney function (CrCl) Cockcroft–Gault, the renal fraction and a longer half-life.
• Which weight for CrCl Ideal, adjusted or actual weight in Cockcroft–Gault, and the trough it predicts.
• Volume of distribution Dilution, half-life and why AUC can stay put.
• Dosing by weight The same dose in a smaller body, and why mg/kg evens it out.
• Double the dose Linearity: twice the levels, the same half-life.
• Flip-flop kinetics When slow absorption sets the tail, not elimination.
• Saturable elimination A third more dose, more than twice the level.
• One or two compartments The same clearance and the same AUC, but a different peak.
• Hemodialysis sessions Clearance that comes and goes.
• Rebound after dialysis Drug the dialyzer couldn't reach comes back.

Repeated dosing and steady state

• Repeated dosing Accumulation, peaks and troughs, steady state.
• Loading dose Reaching the target sooner vs staying there.
• Missed dose The dip, and how long recovery takes.
• Narrow window Fitting a regimen between effective and toxic.
• Short vs long half-life Dosing frequency and accumulation trade-offs.
• Once vs twice daily Same daily dose, different swing.

Custom regimens

• Evenly spaced vs bunched doses When you take a dose matters, not just how much.

Infusion and route

• Bolus vs infusion Controlling the peak with infusion duration.
• Short vs long infusion The same dose, a different exposure shape.
• Loading bolus + infusion Reaching the plateau in minutes, not hours.
• Continuous vs intermittent The same amount as a steady drip or in pulses.
• Time above the MIC The same dose, longer above the MIC.

PK/PD concepts

• Potency (EC50) Same levels, less effect: needing more drug, not a weaker drug.
• Efficacy (Emax) A ceiling no dose can break through.
• Hill slope A graded response vs an on/off switch.
• Dose vs duration of effect Doubling the dose buys one half-life.
• Effect delay (hysteresis) The same levels, a later and lower effect.
• Indirect response When the effect waits for the body to clear what it has.

Liver and first pass

• Hepatic extraction Induction doubles a low-extraction drug's clearance.
• First pass and induction Clearance barely moves; oral exposure halves.
• Liver blood flow A high-extraction drug's clearance follows the flow.

Antimicrobial PK/PD

• Extended infusion The same 12 g a day, longer above the MIC.
• Once daily vs divided The same daily dose: peak vs time above the MIC.

Levels and individualization

• One level and a prior A single well-timed level, weighed against the patient model.

Clinical cases

Students propose a dose and an interval; the model grades it at steady state and explains why. No case stores an answer, and the cases teach reasoning, not prescribing.

• Gentamicin with reduced kidney function Aminoglycoside, peak and trough
• Gentamicin after burns: individualizing from two levels Aminoglycoside, Sawchuk–Zaske
• Levetiracetam with reduced kidney function Antiseizure, label renal table
• Meropenem with reduced kidney function Carbapenem, label renal table
• Piperacillin-tazobactam with reduced kidney function Penicillin, label renal table, fT>MIC
• Gentamicin on hemodialysis Aminoglycoside, dose after each session
• Gentamicin once daily (extended interval) Aminoglycoside, Hartford approach
• Vancomycin to an AUC target Glycopeptide, AUC24
• Vancomycin: the AUC from two levels Glycopeptide, two-level AUC
• Vancomycin: two levels an hour apart Glycopeptide, Bayesian estimate
• Gentamicin: when the second level comes back higher Aminoglycoside, Bayesian estimate
• Phenytoin: a low level and low albumin Saturable kinetics, albumin
• Digoxin in an older adult Narrow window, ng/mL
• Theophylline in a smoker Narrow window, clearance factor
• Lithium with lower kidney function Renal elimination, mEq/L
• A late dose: which drug minds? Half-life reasoning

Practice and worksheets

• Single dose (13 kinds)
• Repeated dosing (8 kinds)
• Infusions (6 kinds)
• Concentration–effect (6 kinds)
• Saturable (Michaelis–Menten) (4 kinds)
• Liver and first pass (3 kinds)
• Antimicrobial PK/PD (3 kinds)

Open the Practice tab for a problem with a worked solution, a worksheet that rebuilds from its link, and the Fit the data and Hit the window exercises.

Privacy and accessibility

No accounts, no server and no tracking. Links carry their settings in the URL; saved work stays in the browser. Ask students not to enter patient-identifying information. The app works offline after one visit, has a light theme for projectors, keyboard controls for the charts, and text descriptions for screen readers.

Feedback

An instructor's view helps most: what would make MaatiRx more useful in your course, or a case or worksheet you would like built. Use the educator form on GitHub.

MaatiRx 2.20.0, MIT license. Source on GitHub; validation.