The context-sensitive half-time is the time required for blood or plasma concentrations of a drug to decrease by 50% after discontinuation of drug administration. The context-sensitive half-time often cannot be predicted by the elimination half-life (a measure of the time needed for actual drug metabolism or elimination) since it also depends on drug distribution. The context-sensitive half-time is a function of the duration of drug administration and may only be estimated by computer simulation. It is more relevant than other isolated pharmacokinetic parameters to understanding the kinetics of drug concentrations. However, understanding the kinetics of drug effect requires concomitant consideration of pharmacodynamics.