Pharmacodynamics

Introduction to Pharmacodynamics00:00:07

An overview of pharmacodynamics, differentiating it from pharmacokinetics (what the body does to the drug versus what the drug does to the body). It discusses the importance of receptors in mediating cellular responses.

Extracellular Receptor Types00:04:19

Detailed explanation of ligand-gated ion channels, G protein-coupled receptors (including Gq, Gs, and Gi pathways), and tyrosine kinase receptors, focusing on how these systems amplify signals.

Intracellular Receptors01:17:48

Explanation of how hydrophobic, small molecules (like steroids) pass through the cell membrane to bind to intracellular receptors that regulate gene transcription.

Tachyphylaxis and Tolerance00:20:05

Defining desensitization mechanisms, including receptor internalization and decreased synthesis, and distinguishing between rapid tachyphylaxis and chronic drug tolerance.

Dose-Response Relationships00:29:04

Analysis of the sigmoidal dose-response curve, defining potency (affinity) and efficacy (maximal effect), and illustrating how these concepts are represented graphically.

Therapeutic Index and Safety00:43:07

Explanation of the therapeutic index (TD50/ED50) as a measure of drug safety, highlighting drugs with narrow versus wide windows and the clinical need for monitoring.

Agonists, Antagonists, and Inverse Agonists00:49:00

Distinguishing between full agonists, partial agonists, inverse agonists, and competitive versus non-competitive antagonists, including their effects on Emax and potency.