Every time a doctor prescribes a medicine and every time a pharmacist dispenses it, the principles of Pharmacology I are at work — ADME, receptor theory, drug interactions, therapeutic index, and autonomic nervous system pharmacology. This is the B Pharma 4th semester subject where pharmacology truly begins — moving from the “what” of drugs to the “how” and “why” of their action inside the human body.
These Pharmacology I notes are prepared as per the PCI-approved B Pharma 4th semester syllabus 2025–26, covering general pharmacology principles, pharmacokinetics, pharmacodynamics, autonomic nervous system drugs, and CNS pharmacology — from antiepileptics and antipsychotics to opioid analgesics and drugs for Parkinson’s disease. Each unit has a clear topic summary. Pharmacology I is one of the most important GPAT subjects — general pharmacology principles, ADME, therapeutic index, drug interactions, and ANS drug classification are tested in virtually every GPAT paper.
Download Pharmacology I Notes PDF – Unit Wise
Click below to download free PDFs for each unit:
Course Units
Unit 1: General Pharmacology Basics
Topics Covered: the fundamentals of pharmacology including drug sources, routes of administration, receptor concepts, tolerance, dependence, and core pharmacokinetics involving absorption, distribution, metabolism, and excretion.
Unit 2: General Pharmacology: Pharmacodynamics & Drug Development
Topics Covered: Includes mechanisms of drug action, receptor types, signal transduction pathways, dose–response relationships, therapeutic index, drug interactions, adverse effects, and stages of drug discovery, clinical trials, and pharmacovigilance.
Unit 3: Pharmacology of Peripheral Nervous System Drugs
Topics Covered: Focuses on autonomic nervous system organization, neurotransmission, cholinergic and adrenergic drugs, neuromuscular blockers, local anesthetics, and medicines used for myasthenia gravis and glaucoma.
Unit 4: CNS Pharmacology: Neurotransmission & Major Drug Classes
Topics Covered: Explains central neurotransmitters, general anesthetics, sedatives, hypnotics, centrally acting muscle relaxants, antiepileptics, and alcohol-related pharmacology.
Unit 5: CNS Pharmacology: Psychopharmacology & CNS Modulators
Topics Covered: antipsychotics, antidepressants, anxiolytics, mood stabilizers, hallucinogens, drugs for Parkinson’s and Alzheimer’s disease, CNS stimulants, nootropics, opioid analgesics, and concepts of addiction and dependence.
What is Pharmacology – I?
Pharmacology – I is a foundational pharmacy subject that introduces the science of drugs and their effects on living systems. It helps students understand how medicines produce therapeutic actions, how they interact with body organs, and how they are used in the treatment of diseases.
This subject forms the base for advanced pharmacology by explaining the principles behind drug action, dosage, safety, and response in the human body.
These notes will help you understand topics like:
- General Principles of Pharmacology
Introduction to pharmacology, sources of drugs, routes of administration, dosage forms, and factors affecting drug response. - Pharmacokinetics Basics
Study of absorption, distribution, metabolism, and excretion of drugs in the body. - Pharmacodynamics
How drugs produce their effects through receptors, enzymes, and other biological targets. - Autonomic Nervous System Drugs
Medicines acting on sympathetic and parasympathetic systems, influencing heart rate, glands, and smooth muscles. - Drugs Acting on the Central Nervous System
Basic introduction to sedatives, analgesics, anesthetics, and other CNS-active drugs. - Cardiovascular Pharmacology
Medicines affecting heart function, blood pressure, and circulation. - Adverse Drug Reactions and Toxicity
Side effects, poisoning, contraindications, and safe use of medicines. - Drug Interactions and Therapeutic Uses
How medicines interact with each other and their practical clinical applications.
This subject provides a strong conceptual base for understanding medicines, helping students progress toward clinical pharmacy, therapeutics, and patient-centered healthcare.
Frequently Asked Questions (FAQ)
Q1. What is the difference between pharmacokinetics and pharmacodynamics?
Pharmacokinetics describes what the body does to the drug — absorption, distribution, metabolism, and excretion (ADME). Pharmacodynamics describes what the drug does to the body — mechanism of action, receptor interactions, dose-response relationships, and therapeutic effects. Together, PK and PD determine the clinical outcome of drug therapy. Both are covered in Units 1 and 2.
Q2. What is the therapeutic index and why is it important?
The therapeutic index (TI) is the ratio of the toxic dose to the effective dose (TD50/ED50). A high TI means the drug is relatively safe — there is a large margin between therapeutic and toxic doses. A low TI (narrow therapeutic index) means small dose changes can cause toxicity — drugs like warfarin, lithium, digoxin, and phenytoin have narrow TIs requiring careful monitoring. Covered in Unit 2.
Q3. What are the key differences between cholinergic and adrenergic drugs?
Cholinergic drugs act on receptors for acetylcholine (muscarinic and nicotinic receptors) in the parasympathetic nervous system. They either mimic acetylcholine (parasympathomimetics) or block its action (parasympatholytics/anticholinergics). Adrenergic drugs act on receptors for noradrenaline and adrenaline (alpha and beta receptors) in the sympathetic nervous system. They either mimic sympathetic effects (sympathomimetics) or block them (sympatholytics). Both drug classes are comprehensively covered in Unit 3.
Q4. What is neurohumoral transmission?
Neurohumoral transmission is the process by which nerve impulses are transmitted from one neuron to another or to an effector organ through chemical messengers (neurotransmitters) released at synapses. In the autonomic nervous system, acetylcholine and noradrenaline are the primary neurotransmitters at different synapses. Understanding neurohumoral transmission is essential for understanding how ANS drugs work. Covered in Unit 3.