BASIC PHARMACOLOGY CONCEPTS

BASIC PHARMACOLOGY CONCEPTS

Introduction to Pharmacology

  • Pharmacology is the study of how medications work in the body.
  • Understanding pharmacology is essential for comprehending the rationale behind physicians' medication prescriptions for specific medical conditions.

Basic Actions of Drugs

  • The pharmacological effects of drugs on the body can be categorized into four basic actions:

    • Absorption:

    • Definition: The process by which a drug enters the body and is made available for activity.

    • Key Factors Influencing Absorption:

      • Route of administration (oral, intravenous, etc.)
      • Drug formulation (tablets, liquids, injections)
      • Physiochemical properties (solubility, stability, etc.)

    • Distribution:

    • Definition: The dispersion of the drug throughout the fluids and tissues of the body after absorption.

    • Considerations:

      • Blood flow to tissues
      • Affinity of the drug for different tissues
      • Influence of plasma protein binding on distribution

    • Metabolism:

    • Definition: The biochemical modification of pharmaceuticals by living organisms, usually through specialized enzymatic systems.

    • Importance: Metabolism typically transforms drugs into more water-soluble compounds to aid in excretion.

    • Phases of Metabolism:

      • Phase I: Modification through oxidation, reduction, or hydrolysis.
      • Phase II: Conjugation with an endogenous substance to enhance water solubility for excretion.

    • Excretion:

    • Definition: The process of eliminating drugs and their metabolites from the body.

    • Organs Involved:

      • Primarily the kidneys (urinary excretion)
      • Liver (biliary excretion)

    • Factors Affecting Excretion:

      • Kidney function
      • Age and health status of the individual

Overview

  • The basic actions of drugs (absorption, distribution, metabolism, excretion) serve as a framework through which the pharmacodynamics and pharmacokinetics of any medication can be understood.
  • Understanding these actions helps in optimizing drug therapy for various medical conditions.