Defined term · Pharmacology
Half-life
The time for a plasma concentration to fall by half during the terminal elimination phase. Determines dosing interval, time to steady state and the time required for washout.
§1Half-life
§1.1Also known as
Terminal half-life t½
§1.2Category
Pharmacology — Terms describing how a compound acts and how the body handles it.
§1.3Related terms
- Steady state — The condition in which the amount of a compound entering the body equals the amount leaving it. Reached after approximately four to five half-lives of repeated dosing.
- Washout — A period between treatments in a crossover design intended to allow the effect of the first to dissipate. A washout shorter than approximately five half-lives leaves…
Compound Evidence Institute · CEI-GT-106 · https://compoundevidence.com/glossary/half-life/ · retrieved 30 July 2026