Drug Action Introduction

Module 3: Drug Action Overview

Introduction to Drug Action

• The session introduces Module 3, focusing on key concepts in pharmacology including pharmaceutics, pharmacokinetics, pharmacodynamics, and pharmacotherapeutics.

• Learning outcomes include the ability to discuss drug action phases and processes before absorption, as well as understanding nursing implications related to these phases.

Phases of Drug Action

• Drug action is illustrated by tracking a drug molecule from administration through its interaction with target sites until elimination.

• Nurses must understand how drugs are administered (e.g., tablets vs. injections) and monitor patient responses throughout the process.

Basic Areas of Pharmacology

• A tablet or capsule undergoes three main phases during drug action: pharmaceutics, pharmacokinetics, and pharmacodynamics.

Pharmaceutics Phase

• In this phase, the drug becomes a solution to cross biological membranes effectively.

Pharmacokinetics Phase

• This phase consists of four processes:

• Absorption: The drug crosses biological membranes.

• Distribution: The drug targets specific cells.

• Metabolism (or biotransformation): The chemical alteration of the drug in the body.

• Excretion: Elimination of the drug from the body.

Pharmacodynamics Phase

• This phase studies the physiological response resulting from drug interactions with receptors in the body.

Relationship Between Dose and Effect

• Pharmaceutics examines how dosage forms influence a drug's effect on the body; pharmacokinetics focuses on what happens to a drug within the body; while pharmacodynamics looks at how drugs affect bodily functions.

Summary of Drug Interaction Process

• The process begins with disintegration and dissolution of oral medications leading into absorption during pharmacokinetics.