Introduction to Pharmacology

Introduction to Pharmacology is the study of drugs, their sources, properties, mechanisms, therapeutic uses, and effects on living systems.

Definition of Pharmacology

• Pharmacology is the branch of science that deals with the study of drugs, including their origin, nature, properties, actions, and effects on living organisms.
• It is primarily divided into two major branches:
• Pharmacodynamics – What the drug does to the body (mechanism of action, therapeutic effect).
• Pharmacokinetics – What the body does to the drug (absorption, distribution, metabolism, excretion).
• Pharmacology helps to understand the interaction between drugs and biological systems, guiding therapeutic applications and safety considerations.

Pharmacokinetics (PK)

• Pharmacokinetics is the study of what the body does to the drug.
• It involves the movement of drugs through the body and is typically divided into four key processes:

1. Absorption
2. Distribution
3. Metabolism (Biotransformation)
4. Excretion

• These processes determine the onset, intensity, and duration of a drug’s action.

Historical Landmarks in Pharmacology

• Pharmacology has evolved from traditional herbal remedies to a highly scientific discipline.

Here are important historical milestones:

1. Ancient Era: Early use of medicinal plants and minerals in civilizations such as Egypt, India (Ayurveda), China (Traditional Chinese Medicine), and Greece.
2. Dioscorides (1st Century): Authored De Materia Medica, cataloging medicinal substances from nature.
3. Paracelsus (16th Century): Introduced the principle “the dose makes the poison,” emphasizing dose-response relationships.
4. 18th–19th Century: Isolation of active principles like morphine (from opium), quinine (from cinchona bark), and digitalis (from foxglove).
5. 20th Century:
   • Discovery of antibiotics (e.g., penicillin by Alexander Fleming in 1928).
   • Development of vaccines, anesthetics, and chemotherapeutic agents.
   • Establishment of pharmacology as an experimental and clinical science.
6. Modern Era: Introduction of biotechnology, genetic engineering, targeted therapy, and pharmacogenomics.

Scope of Pharmacology

Pharmacology intersects with multiple disciplines:

• Pharmacognosy: Study of drugs derived from natural sources (plants, animals, minerals).
• Pharmaceutics: Formulation and dispensing of drugs.
• Pharmacokinetics and Pharmacodynamics: Essential sub-disciplines focusing on how the body handles drugs and how drugs act on the body.
• Toxicology: Study of harmful effects of chemicals on living organisms.
• Clinical Pharmacology: Application of pharmacological principles in the clinical setting.
• Pharmacovigilance: Monitoring and evaluating drug safety post-marketing.

The ultimate scope is to improve the use of drugs to optimize therapeutic outcomes and minimize adverse effects.

Importance:

• Development of safer and more effective drugs.
• Rational and evidence-based drug therapy.
• Regulation and monitoring of drug use.

Thank you for reading from Firsthope's notes, don't forget to check YouTube videos!