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Chapter Objectives

After reading this chapter, the student will be able to:

  1. Understand and be able to define the term “drug.”

  2. Know about the process by which drug compounds are attached to receptor sites located on or within the cell.

  3. Be able to differentiate between the agonist and antagonist effects of a drug on living tissues.

  4. Understand the differences in individual responses to drug therapy.

  5. Understand the onset and duration of action that drugs exhibit when administered to living tissues.

  6. Understand and be able to identify the various methods in which a drug can be administered.

  7. Be able to differentiate among the different types and sites of drug administration.

  8. Understand how drugs are absorbed, metabolized, distributed, and excreted.

  9. Be able to identify the variety of human physical characteristics that may affect drug responses.

Chapter Outline

  • What Is a Drug?

  • Pharmacodynamics

    • Receptor Sites

    • Dose Response

    • Time Response

    • Therapeutic Index

    • Plasma Dose Response

    • Half-life

  • Pharmacokinetics

    • Absorption

    • Distribution

    • Metabolism

    • Excretion

  • Factors Affecting Drug Response

  • Barriers to Drug Distribution

  • Drug Safety

  • Scenario From the Field

  • Discussion Topics

  • Chapter Review

Each year over-the-counter (OTC) and prescription drug administration rates increase. As more and more new drugs, both prescription and OTC, are developed for a variety of maladies, the athletic trainer needs to be more knowledgeable about how these drugs affect the human body. It is important to understand the different methods of delivering drugs to the tissues and how these methods affect how it is metabolized and utilized by the body.

This chapter will explain how drugs are used to treat, prevent, and diagnose disease and illness, a field of study known as pharmacotherapeutics. Specifically, this chapter will focus on two subcomponents of pharmacotherapeutics: pharmacokinetics (how the body assimilates, incorporates, and eliminates a drug) and pharmacodynamics (how a drug affects the body). By gaining a basic understanding of the pharmacotherapeutics of both prescription and OTC drugs, you can explain to athletes why it is important to take medications as prescribed by the physician. You will also have a better understanding of how drugs work within the body, why they work, how long a drug remains active, and potential drug adverse effects. You will also be able to address many other general questions athletes typically ask when they are taking a drug.


A drug is a chemical that interacts with and affects living organisms to produce a biological response. In other words, a drug alters physiological functions by replacing, interrupting, or potentiating existing cellular functions. For example, caffeine, a drug found in coffee, tea, soft drinks, and other foods, can produce a stimulant effect on the central nervous system (CNS) by attaching to its receptors and essentially overriding fatigue messages sent to the brain from various neurotransmitters. The actions of caffeine at the cellular level allow it to assist with headache relief and induce alertness ...

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