title: Plasma terminal half-life.
abstract: 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.
authors.affiliation: UMR 181 Physiopathologie et Toxicologie Expérimentales INRA/ENVT, Ecole Nationale Vétérinaire de Toulouse, Toulouse cedex 03, France. pl.toutain@envt.fr
authors.forename: P L
authors.initials: PL
authors.lastname: Toutain
authors.forename: A
authors.initials: A
authors.lastname: Bousquet-Mélou
mesh_terms: D000818:Animals; D006207:Half-Life; D023421:Models, Animal; D008954:Models, Biological; D010949:Plasma / Q000378:metabolism*; D019155:Veterinary Drugs / Q000493:pharmacokinetics*
chemical_list: D019155:Veterinary Drugs