Pharmacokinetics Suite (loading / maintenance / half-life)
Pharmacokinetics suite (Rowland & Tozer): loading dose = Vd·Cp/(S·F), maintenance = CL·Css·τ/(S·F), k = CL/Vd, half-life = ln2·Vd/CL, steady state ≈ 5·t½.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Volume of distribution Vd
- 50
- Clearance CL
- 5
- Target concentration Cp
- 20
- Bioavailability F
- 1
- Dosing interval τ
- 12
Result: Half-life 6.93 h; steady state ~34.65 h; loading dose 1000 mg; maintenance 1200 mg.
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Formulas
- loading = Vd·Cp/(S·F); maintenance = CL·Css·τ/(S·F); k = CL/Vd; t½ = ln2·Vd/CL; steady state ≈ 5·t½; top-up = Vd·(target − measured)/(S·F); proportional dose = dose·target/measured.
- Scope
- Point estimates requiring individualization and monitoring; not a Bayesian/population estimator (vanc-auc owns vancomycin-specific AUC math).
What you enter
- Volume of distribution Vd (L)
- Clearance CL (L/h)
- Target concentration Cp (mg/L)
- Bioavailability F (0–1)
- Dosing interval τ (h)
- Salt factor S (0–1)
- Measured concentration (mg/L)
- Current dose (mg)
How this is calculated
Citation
Rowland M, Tozer TN. Clinical Pharmacokinetics and Pharmacodynamics: Concepts and Applications. 4th ed. Philadelphia: Lippincott Williams & Wilkins; 2011 (first-order PK relations). Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.