Fundamentals of Drug Action

This chapter is a brief review of the mechanistic aspects of drug action and discusses the concepts of receptors and drug receptor interactions critical for pharmacological responses of drugs. After study of this chapter, students will be able to: • Discuss about receptors from historical perspectives • Explain the mechanistic principles of drug action in light of receptors • Summarize different theories of drug action such as: - Occupancy Theory - Rate Theory - Induced-Fit Theory - Macromolecular Perturbation Theory - Occupation-Activation Theory of “Two-State” Model • Understand drug receptor interactions

Keywords: Affinity, Agonist, Antagonist, Drug receptor interaction, Efficacy, Intrinsic activity, Partial agonist, Receptor, Theories of drug action.