The following pharmacology definition has been taken from the Pharmacology and Experimental Therapeutics Department Glossary at Boston University School of Medicine.
A larger than normal dose (D*) administered as the first in a series of doses, the others of which are smaller than D* but equal to each other. The loading dose is administered in order to achieve a therapeutic amount in the body more rapidly than would occur only by accumulation of the repeated smaller doses. The smaller doses (D) which are given after D* are called “maintenance doses”. The effect of D* on C becomes relatively less with each succeeding maintenance dose; finally Css,max and Css,min are determined by D, and are uninfluenced by D*.
The relative sizes of D and D* can be adjusted so that peak plasma concentrations (Cmax) are the same following every dose, including the first with D*, and all are equal to Css,max. These conditions are met when D/D* = 1-f.
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