Transcript 1st & 2nd Lectures

Pharmacology 101
Abdelkader Ashour, Ph.D.
1st & 2nd Lectures
Overview
A. Introduction
-Definitions
-Drug Sources
-Drug Nomenclature
B. Basic concepts in Pharmacology
-Drug-Body Interactions
-Drug Receptors
-Drug Receptor Interactions
Pharmacology, link to other biomedical principles
Pharmacology, Definitions
 Pharmacology
“A branch of medical sciences that study drugs and their action on living
organisms”
 Why do nurses study pharmacology? A sound knowledge of basic pharmacologic
principles is essential if the nurse is to safely administer medications and to
monitor patients who receive these medications
 Drug
“Any substance that brings about a change in biologic function through its
chemical actions”
 Receptor
“A specific protein in either the plasma membrane or interior of a target cell
with which a chemical messenger/drug combines”
 Mechanism of Action
“The ways by which drugs can produce therapeutic effects”
 Dose
“The amount of a drug to be administered at one time”
Pharmacology, Definitions
 Effects (therapeutic effect)
“The desired results of
administration of a medication”
 Side Effects (adverse effects)
“Effects that are harmful and
undesired, and that occur in
addition to the desired therapeutic
effects”
 Indications
“The reasons for administering a medication or performing a treatment”
 Contra-indications
“Factor that prevents the use of a medication or treatment (e.g., Allergies)”
Pharmacology, Definitions
 Onset
“The time it takes for the drug to elicit a therapeutic response”
 Duration
“The time a drug concentration is sufficient to elicit a therapeutic response”
The Role of Nurses in Relation to
Pharmacology

Nurses play an active role in drug administration

Nurses contribute to the planning and modification of drug therapy from their
assessment of patient factors and evaluation of progress or problems
occurring during drug therapy



In addition to: the role in patient education and compliance
Nurses share information with other health care professionals to provide the
most effective medication regimen for the patient
Nurses have to follow the “Five Rights” of Medication Administration
1.
Right drug
2.
Right dose
3.
Right time
4.
Right route
5.
Right patient
Drug Sources
1. Plant Sources: Obtained from plant parts or products. Seeds, stem,
roots, leaves, resin, and other parts yield these drugs.
Examples include digoxin from digitalis and morphine from opium.
2. Animal Sources: Glandular products from animals are used, such as
insulin and thyroid.
3. From micro-organisms (fungi, bacteria) Penicillin was discovered by
Alexander Fleming in 1928 as a product of penicillium notatum (a mold
growing in his lab)
4. Mineral Sources: Some drugs are prepared from minerals, for example,
lithium carbonate (an antipsychotic), MgSO4 (a laxative)
5. Synthetic Sources: Laboratories duplicate natural processes, and may
modify the products. Frequently this can eliminate side effects and
increase the potency of the drug.
Examples include sulfonamides, and aspirin.
6. Recombinant proteins: Proteins that are synthesized by expression of
cloned genes in recombinant cells, such as interferons, antibodies
Drug Nomenclature
 Chemical name  represents the exact description of the drug’s chemical
composition
 Generic name (non-proprietary) 
- simpler than the chemical name and
- derived from the chemical name itself
- easier to remember
 Example 1: the chemical name 2-methyl-5-nitroimidazole-l-ethanol is
metronidazole. The word methylnitro is condensed to metro and ni-dazole is due
to its imidazole ring
 Example 2: Metoclopramide is the condensed form of the word
methoxychloroprocainamide: where Me is retained and th is written as t; chloro
is written as clo: and procainamide is written as pramide
 Brand or trade name (proprietary)  is developed by the company requesting
approval for the drug and identifies it as the exclusive property of that company.
 Example 1: Metrogyl® is the trade name for metronidazole.
 Example 2: Reglan® is the trade name for Metoclopramide.
 Example 3: Amoxil® is the trade name for amoxycillin.
 Example 4: Celebrex® is the trade name for Celecoxib.
Overview
A. Introduction
-Definitions
-Drug Sources
-Drug Nomenclature
B. Basic concepts in Pharmacology
-Drug-Body Interactions
-Drug Receptors
- Drug Receptor Interactions
Drug-Body Interactions
Pharmacokinetics
 Pharmacokinetics (in Greek: "pharmacon" meaning drug, and "kinetikos"
meaning putting in motion)
 The study of the movement of drugs in the body, including the processes of
absorption, distribution, metabolism and excretion (ADME)
 The drug should be in an adequate concentration at the site of action to
produce its effects. This depends on ADME.
Pharmacodynamics
 The study of the action or effects of drugs on living organisms
Pharmacokinetics
What the body does to the drug
vs
Pharmacodynamics
What the drug does to the body
Drug Receptors
 Receptor/Binding site
“A specific protein in either the plasma
membrane or interior of a target cell with
which a ligand/drug combines”
 It must be selective in choosing ligands/drugs
to bind  To avoid constant activation of the
receptor by promiscuous binding of many
different ligands (drugs)
 It must change its function upon binding in
such a way that the function of the biologic
system (cell, tissue, etc) is altered  This is
necessary for the ligand (drug) to cause a
pharmacologic effect
Drug Receptors
 Receptor/Binding site
“A specific protein in either the plasma
membrane or interior of a target cell with
which a ligand/drug combines”
 It must be selective in choosing ligands/drugs
to bind  To avoid constant activation of the
receptor by promiscuous binding of many
different ligands (drugs)
 It must change its function upon binding in
such a way that the function of the biologic
system (cell, tissue, etc) is altered  This is
necessary for the ligand (drug) to cause a
pharmacologic effect
Drug Receptors
 Receptor/Binding site
“A specific protein in either the plasma
membrane or interior of a target cell with
which a ligand/drug combines”
 It must be selective in choosing ligands/drugs
to bind  To avoid constant activation of the
receptor by promiscuous binding of many
different ligands (drugs)
 It must change its function upon binding in
such a way that the function of the biologic
system (cell, tissue, etc) is altered  This is
necessary for the ligand (drug) to cause a
pharmacologic effect
Drug Receptor Interactions
The Lock and Key Model of Signal-Receptor
Interaction
 Ligands such as hormones or neurotransmitters (the"key")
affect target cells by binding to specific receptors (the
"lock”), which are often located in the cell membrane
 This binding "unlocks" the cell's response, so that the
hormone or neurotransmitter can exert its effects
 Agonist
“A chemical messenger that binds to a receptor and triggers the cell’s
response; often refers to a drug that mimics a normal messenger’s action”.
 For example, pilocarpine is a muscarinic receptor agonist because it can bind to and
activate muscarinic receptors
 Antagonist
"A molecule that competes for a receptor with a chemical messenger normally
present in the body. The antagonist binds to the receptor but does not trigger
the cell’s response”
 For Example, atropine is a muscarinic receptor antagonist because it can bind to
muscarinic receptors but it does not trigger the cell’s response. In this way, it prevents
binding of acetylcholine (ACh) and similar agonist drugs to the ACh receptor
Drug Receptor Interactions
Lock and key mechanism
Agonist
Receptor
Agonist-Receptor
Interaction
Drug Receptor Interactions
Competitive
Inhibition
Antagonist
Receptor
DENIED!
Antagonist-Receptor
Complex