Work out drug half life elimination instantly with clear inputs, formula shown and shareable results.
Applies first-order elimination to find the concentration remaining after a given time, together with the elimination rate constant.
First-order elimination
C(t) = C0 x 0.5^(t / half-life); elimination rate constant ke = ln 2 / half-life
Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
About 97% is gone after five half-lives and over 99% after seven.
Only to first-order kinetics. Phenytoin, alcohol and high-dose salicylate show saturable zero-order elimination.