Glossary
Half-life
Also written elimination half-life
The time it takes for half of a compound to be cleared from the body.
Half-life determines how often something needs to be taken and how long it lingers after the last dose. A compound with a one-week half-life is still substantially present a fortnight later; one with a half-life of minutes is not.
It is also why compounds with long half-lives are escalated slowly in trials. The effect of a dose increase is not fully visible for several weeks.
Relevant compounds