ABSTRACT
This chapter describes three components that aim to explain the observed differences in responses to individual drugs: pharmacology, pharmacoepidemiology, and pharmacogenetics. At the clinical level, variability in drug response can be explained by its pharmacology that describes the pharmacokinetic and pharmacodynamic profiles of the drug. Pharmacokinetics explain “what the body does to the drug” by describing the relationship between time and plasma concentrations of the drug metabolites. Pharmacoepidemiology is a sub discipline of epidemiology that focuses on understanding why individuals respond differently to drug therapy. Pharmacoepidemiology, through the use of observational methods, aims to quantify drug exposure and to describe, as well as predict, the effectiveness and safety of the drug within defined populations at specific places and time. Pharmacogenetics, a third and important component of individualized therapy, focuses on describing the extent to which an individual’s genetic makeup is responsible for the observed differences in drug efficacy and toxicity profiles.
