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This chapter will be most useful after having a basic understanding of the material in Chapter 3, Pharmacodynamics: Molecular Mechanisms of Drug Action in Goodman & Gilman’s The Pharmacological Basis of Therapeutics, 12th Edition. Additional information related to this chapter is provided in Chapter 1, Drug Invention and the Pharmaceutical Industry and Chapter 7, Pharmacogenetics. The drugs presented in this chapter are used to illustrate general pharmacodynamic principles. The mechanisms of action and therapeutic uses of drugs described in this chapter are discussed in more detail in subsequent chapters. Neither a Mechanisms of Action Table nor a Clinical Summary Table is included in this chapter because this information is provided in subsequent chapters.


In addition to the material presented here, Goodman & Gilman’s The Pharmacological Basis of Therapeutics, 12th Edition contains:


  • A description in Chapter 1 of the process of drug invention and FDA approval

  • Table 1-1, Typical Characteristics of the Various Phases of the Clinical Trials Required for Marketing of New Drugs

  • Figure 1-1, The Phases, Time Lines, and Attrition That Characterize the Invention of New Drugs

  • A comprehensive description in Chapter 3 of the various mechanisms of drug action, including cellular pathways activated by physiological receptors, structural and functional families of physiological receptors, second messengers, ion channels, nuclear receptors, and transcription factors

  • Chapter 3 also describes mechanisms of receptor desensitization and regulation, and an example of pharmacodynamic interactions in a multicellular context

  • Chapter 7 includes a number of examples of genetic polymorphisms that affect drug pharmacodynamics, the impact of pharmacogenetics on drug development, and a discussion of pharmacogenetics in clinical practice




  • Understand key concepts and terms related to pharmacodynamics, including drug receptor agonism and antagonism.

  • Know concepts and terms that are used to quantify drug receptor interactions, including affinity, efficacy, potency, KD and Ki.

  • Understand how drug pharmacodynamic information is used to predict beneficial and toxic drug effects.

  • Know the modern process of drug invention and FDA approval, and post-market surveillance.

  • Know how genetic polymorphisms and other factors can affect the pharmacodynamic properties of drugs and lead to variability in individual patient responses to drugs.

  • Know how pharmacodynamics is applied to populations of patients to estimate population therapeutic windows for drug dosing.


PHARMACODYNAMIC CONCEPTS AND NOMENCLATURE (key terms are indicated in italics)

  • Pharmacodynamics is the study of the biochemical and physiological effects of drugs and their mechanisms of action.

  • Pharmacodynamics refers to the effects of a drug on the body; in contrast, the effects of the body on the actions of a drug are pharmacokinetic processes (see Chapter 2).

  • The term drug receptor or drug target denotes the cellular macromolecule or macromolecular complex with which the drug interacts to elicit a cellular response.

  • Drugs commonly alter the rate or magnitude of an intrinsic cellular response rather than create new responses.

  • Drug receptors are ...

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