Pharmacology is the science that studies substances that interact with living systems through chemical processes.
These substances work mainly by binding to regulatory molecules.
They can activate or inhibit normal body functions.
These substances are usually given as drugs to produce beneficial therapeutic effects in patients.
Pharmacology is a branch of medicine that combines several biomedical sciences, including:
Chemistry
Biochemistry
Physiology
Clinical medicine
Pharmacology is both:
A basic science.
An applied science.
Pharmacology is the foundation of rational drug therapy.
Pharmacology studies:
Sources of drugs.
Biochemical effects of drugs.
Physiological effects of drugs.
Mechanism of action of drugs.
Therapeutic uses of drugs.
Adverse effects of drugs.
Pharmacology also explains:
What effects drugs produce.
How drugs produce those effects.
Example: Paracetamol
Lowers body temperature during fever.
It works by inhibiting the enzyme cyclooxygenase (COX) in the CNS.
This reduces the production of inflammatory mediators.
Example: Penicillin
Treats certain bacterial infections.
It inhibits a key enzyme needed for bacterial cell wall synthesis.
As a result, bacterial cell walls cannot form properly.
In 1966, the World Health Organization (WHO) defined a drug as:
Any substance or product used or intended to modify or study physiological systems or pathological conditions for the benefit of the patient.
According to the New Drugs and Clinical Trials Rules, 2018 (India):
An Active Pharmaceutical Ingredient (API) is any substance used in a pharmaceutical formulation.
It provides pharmacological activity.
It may also directly help in:
Diagnosis
Cure
Mitigation
Treatment
Prevention of disease
Restoring normal physiological functions
Correcting physiological functions
Modifying physiological functions
It can be used in both humans and animals.
Drugs are chemical substances that affect living organisms.
Clinicians use drugs to:
Diagnose diseases.
Prevent diseases.
Treat diseases.
Safe use of drugs requires knowledge of:
Mechanism of action.
Drug doses.
Routes of administration.
Adverse drug effects.
Drug interactions.
Medicinal or organic chemists create a new candidate molecule called a New Chemical Entity (NCE).
Pharmacologists test the NCE:
In vitro.
On isolated tissues.
In cell cultures.
In animals (in vivo).
In humans.
Successful testing can lead to the discovery of new therapeutic drugs.
General pharmacology includes the study of:
Sources of drugs.
Routes of drug administration.
Drug absorption.
Factors affecting absorption.
Drug distribution.
Drug biotransformation (metabolism).
Drug excretion.
Drug–receptor interaction.
Mechanism of drug action.
Adverse drug effects.
Preclinical evaluation.
Clinical evaluation.
KEY CONCEPT
Pharmacology is the science of drugs and their effects on living systems.
It combines chemistry, biochemistry, physiology, and clinical medicine.
It explains drug sources, actions, uses, adverse effects, and mechanisms.
Drugs act by interacting with regulatory molecules to activate or inhibit body functions.
Safe drug therapy requires understanding drug action, dose, administration, adverse effects, and interactions.
New drugs are developed by creating New Chemical Entities (NCEs) and testing them from laboratory studies to human trials.
General pharmacology mainly covers drug sources, administration, absorption, distribution, metabolism, excretion, receptor interaction, adverse effects, and drug evaluation.
