PHARMACODYNAMICS
Overview
Pharmacodynamics describes the relationship between plasma drug
concentration and pharmacologic effect. Simply stated, pharmacodynamics attempts
to explain what a drug does to the body. Although the study of clinically important
drug effects is multifaceted, we divide pharmacodynamics into three general areas:
transduction of biologic signals (i.e., receptor theory and structure), developments
in molecular pharmacology, and clinical evaluation of drug effects. Each of these
aspects of pharmacodynamics is explored in detail in the following sections.
Figure 3-22
A three-compartment model with an added effect site to
account for the equilibration delay between the rise and fall of arterial drug concentrations
and the onset and offset of drug effect. The effect site is assumed to have a negligible
volume.
