What is Terminal half life?

Answer 1

Terminal plasma half-life is the time required to divide the plasma concentration by two after reaching pseudo-equilibrium, and not the time required to eliminate half the administered dose. When the process of absorption is not a limiting factor, half-life is a hybrid parameter controlled by plasma clearance and extent of distribution. In contrast, when the process of absorption is a limiting factor, the terminal half-life reflects rate and extent of absorption and not the elimination process (flip-flop pharmacokinetics). The terminal half-life is especially relevant to multiple dosing regimens, because it controls the degree of drug accumulation, concentration fluctuations and the time taken to reach equilibrium.

Answer 2

Terminal half-life is the time it takes for the concentration of a drug in the body to decrease by half during the elimination phase, after reaching steady state. It is used to estimate how long a drug will stay in the body once the dosing is stopped. Terminal half-life is influenced by factors such as drug metabolism and elimination rate.