Pharmacology
UG-Course
Touqeer Ahmed PhD
19th February, 2015
Atta-ur-Rahman School of Applied Biosciences
National University of Sciences and Technology
Pharmacology
Course Contents
•
•
•
•
Introduction to Pharmacology
– Drug-Receptor Interactions and
Pharmacodynamics
– Pharmacokinetics
Nervous System Drugs
– The Autonomic Nervous System
– Cholinergic and Adrenergic drugs
– Anxiolytic, Hypnotic, Central Nervous
System Stimulants, Antidepressant
Drugs, and antiepileptics
Cardiovascular Drugs
– Antiarrhythmic Drugs, Antianginal
Drugs, Antihypertensive Drugs, Drugs
Affecting The Blood
Drugs affecting the endocrine system
– Oral Hypoglycemic Drugs
•
•
•
Drugs affecting respiratory and
gastrointestinal systems
Principles of antimicrobial therapy
– Inhibitors of Cell Wall Synthesis
– Protein Synthesis Inhibitors
– Folate Antagonists
– Quinolones, and Urinary Tract
Antiseptics
– Antimycobacterial Drugs
– Antifungal Drugs
– Antiprotozoal Drugs
– Antiviral Drugs
– Anticancer Drugs
– Immunosuppressants
Anti-inflammatory drugs and autocoids
Recommended Books
Pharmacology
Evaluation System
•
•
•
•
•
Assignment
Quiz
First Sessional
Second Sessional
Final Exams (Terminal Exams)
10
20
10
10
50
Introduction to Pharmacology
Pharmacology Today
Basic Concepts in Pharmacology
Basic Concepts in Pharmacology
• Pharmacology (Derived from a Greek word)
• What is a drug?
– For the purposes of this book, a drug can be defined as a chemical substance of
known structure, other than a nutrient or an essential dietary ingredient,1 which,
when administered to a living organism, produces a biological effect.
– To count as a drug, the substance must be administered, rather than released by
physiological mechanisms. Many substances, such as insulin or thyroxine, are
endogenous hormones but are also drugs when they are administered
intentionally.
• What is a medicine?
– A medicine is a chemical preparation, which usually but not necessarily contains
one or more drugs, administered with the intention of producing a therapeutic
(healing/recovery from disease) effect.
– Medicines usually contain other substances (excipients, stabilisers, solvents, etc.)
besides the active drug, to make them more convenient to use.
1Like
most definitions, this one has its limits. For example, there are a number of essential
dietary constituents, such as iron and various vitamins, that are used as drugs/medicines.
Basic Concepts in Pharmacology
• Pharmacodynamics: is the study of the biochemical and
physiological effects of drugs on the body or on
microorganisms or parasites within or on the body and
the mechanisms of drug action and the relationship
between drug concentration and effect.
• Pharmacokinetics: is the study of what the body does to
a drug
Basic Concepts in Pharmacology
• Protein targets for drug binding
Four main kinds of regulatory protein are commonly involved as primary
drug targets, namely:
1.receptors (activate signaling pathways)
2. carrier molecules (transporters)
• Agonists and antagonists
Agonists, which 'activate' the
receptors, and antagonists,
which combine at the same site
without causing activation,
and block the effect of agonists
on that receptor.
3.enzymes
4.ion channels.
Basic Concepts in Pharmacology
THE BINDING OF DRUGS TO RECEPTORS
– Why do we plot it on the Log scale?
Agonists (Types)
•
Agonist: An agonist binds to a receptor and produces a
biologic response. An agonist may mimic the response of the
endogenous ligand on the receptor, or it may elicit a
different response from the receptor and its transduction
mechanism.
•
Full agonists: If a drug binds to a receptor and produces a maximal
biologic response that mimics the response to the endogenous
ligand (e.g. phenylephrine is an agonist at α1-adrenoceptors)
Partial agonists
Partial agonists have efficacies (intrinsic activities) greater than zero
but less than that of a full agonist. Even if all the receptors are
occupied, partial agonists cannot produce an Emax of as great a
magnitude as that of a full agonist. (e.g. aripiprazole, used to treat
schizophrenia)
– A unique feature of these drugs is that, under appropriate
conditions, a partial agonist may act as an antagonist of a full
agonist.
Inverse agonists: Some receptors show a spontaneous conversion
from R to R* in the absence of agonist (that is, they can be active
without the presence of agonist). These receptors, thus, show a
constitutive activity that is part of the baseline response measured
in the absence of drug. Inverse agonists, unlike full agonists, stabilize
the inactive R form. (some scientist categorize these along with
antagonist)
•
•
Agonists (Quantifying Agonism)
Drugs have two observable properties in
biological systems:
– Potency
Potency is controlled by four factors:
1. Receptor density in a tissue
2. Efficiency of the stimulus-response
mechanisms present by default in the
tissue
3. Affinity of the drug for its receptor
4. Efficacy
– Efficacy/Magnitude of effect (when a
biological response is produced)
• The advantage of using efficacy is that
this property depends solely on efficacy,
whereas potency is a mixed function of
both affinity and efficacy