General Principles of Pharmacologic Therapy

This chapter addresses many of the components of clinical pharmacology. Included are pharmacokinetics (PK), pharmacodynamics (PD), pharmacogenomics, and the role of herbal supplements, drugs of abuse, aging, and comorbid medical illness. PD addresses the time course and intensity of drug effects on the body or what the drug does to the body. Variability in PD can exceed that of PK such that similar plasma concentrations can produce different pharmacologic effects in different patients. The chapter discusses the drug-receptor concept, dose-effect relationships, metabolism and its variability, and PD drug interactions. The role of kinetic–dynamic (KD) modeling in clinical pharmacology is reviewed. PD differences are difficult to interpret without concentration data, hence combining PK and PD to address the relationship between concentration and effect is the purpose of KD modeling.