Clearance, half-life, steady state and loading and maintenance doses
Clearance and volume of distribution as the two primary parameters, half-life as their consequence, first-order and zero-order elimination, time to steady state, hepatic extraction ratio, renal excretion, and how to calculate loading and maintenance doses.
Tier 1Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Clearance (CL) is the volume of plasma cleared of drug per unit time. It sets the maintenance dose.
- Volume of distribution (Vd) sets the loading dose (see absorption, bioavailability and distribution).
- Half-life follows from both: t½ = 0.693 × Vd / CL. It decides how long a drug takes to reach steady state and to wash out.
Loading the rest of the note…
Finished reading?
Sources
- Australian Medicines HandbookAU/NZAustralian Medicines Handbook Pty Ltd, 2026
- Goodman & Gilman's The Pharmacological Basis of Therapeutics (14th ed.)McGraw Hill (Brunton and Knollmann, 2023), 2023
- Rang & Dale's Pharmacology (10th ed.)Elsevier (Ritter et al., 2023), 2023
- Prediction of creatinine clearance from serum creatinineNephron (Cockcroft and Gault, 1976;16:31-41), 1976
- Clinical pharmacokinetics of cardiac glycosides in patients with renal dysfunctionClinical Pharmacokinetics (Aronson, 1983;8:155-78), 1983
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Turnstile bot check on sign-in and signed-out feedback