DOR 101 Pharmacology 1st and 2nd

8/2/2019 DOR 101 Pharmacology 1st and 2nd

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Pharmacology 101

Abdelkader Ashour, Ph.D.

1st & 2nd Lectures


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B. Basic concepts in Pharmacology-Drug-Body Interactions-Drug Receptors

-Drug Receptor Interactions

Overview

A. Introduction

-Definitions

-Drug Sources

-Drug Nomenclature


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Pharmacology,link to other biomedical principles


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Receptor

A specific protein in either the plasma membrane or interior of a target cell

with which a chemical messenger/drug combines

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 tomonitor patients who receive these medications

Drug

Any substance that brings about a change in biologic function through itschemical actions

Dose

The amount of a drug to be administered at one time

Mechanism of Action

The ways by which drugs can produce therapeutic effects


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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

Effects (therapeutic effect)

The desired results of

administration of a medication

Side Effects (adverse effects)

Effects that are harmful and

undesired, and that occur inaddition to the desired therapeuticeffects


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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


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The Role of Nurses in Relation toPharmacology

Nurses share information with other health care professionals to provide themost effective medication regimen for the patient

Nurses play an active role in drug administration

Nurses contribute to the planning and modification of drug therapy from theirassessment of patient factors and evaluation of progress or problemsoccurring during drug therapy

In addition to: the role in patient education and compliance

Nurses have to follow theFive Rights of Medication Administration

1. Right drug2. Right dose

3. Right time

4. Right route

5. Right patient


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Drug Sources1. 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.

4. Mineral Sources: Some drugs are prepared from minerals, for example,lithium carbonate (an antipsychotic), MgSO4 (a laxative)

2. Animal Sources: Glandular products from animals are used, such asinsulin and thyroid.

5. Synthetic Sources:Laboratories duplicate natural processes, and maymodify the products. Frequently this can eliminate side effects andincrease 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

3. From micro-organisms (fungi, bacteria)Penicillin was discovered by

Alexander Fleming in 1928 as a product of penicillium notatum (a moldgrowing in his lab)


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Brand or trade name (proprietary)is developed by the company requestingapproval 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.

Drug Nomenclature

Example 1:the chemical name 2-methyl-5-nitroimidazole-l-ethanol ismetronidazole. The word methylnitro is condensed to metro and ni-dazole is dueto its imidazole ring

Example 2:Metoclopramide is the condensed form of the wordmethoxychloroprocainamide: where Me is retained and th is written as t; chlorois written as clo: and procainamide is written as pramide

Chemical namerepresents the exact description of the drugs chemicalcomposition

Generic name (non-proprietary)-simpler than the chemical name and- derived from the chemical name itself- easier to remember


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B. Basic concepts in Pharmacology-Drug-Body Interactions-Drug Receptors

- Drug Receptor Interactions

Overview

A. Introduction

-Definitions

-Drug Sources

-Drug Nomenclature


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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 ofabsorption, 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.

Pharmacokinetics

Pharmacodynamics The study of the action or effects of drugs on living organisms

Pharmacokinetics vs Pharmacodynamics

What the drug does to the bodyWhat the body does to the drug

Drug-Body Interactions


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Receptor/Binding site

A specific protein in either the plasmamembrane or interior of a target cell withwhich a ligand/drug combines

It must be selective in choosing ligands/drugsto bind To avoid constant activation of thereceptor by promiscuous binding of manydifferent ligands (drugs)

It must change its function upon binding insuch a way that the function of the biologicsystem (cell, tissue, etc) is altered This isnecessary for the ligand (drug) to cause a

pharmacologic effect

Drug Receptors


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Drug Receptors


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Drug Receptors


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The Lock and Key Model of Signal-ReceptorInteraction

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 thehormone or neurotransmitter can exert its effects

Drug Receptor Interactions

AgonistA chemical messenger that binds to a receptor and triggers the cells

response; often refers to a drug that mimics a normal messengers 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 triggerthe cells response For Example, atropine is a muscarinic receptor antagonist because it can bind to

muscarinic receptors but it does not trigger the cells response. In this way, it preventsbinding of acetylcholine (ACh) and similar agonist drugs to the ACh receptor


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Agonist Receptor

Agonist-Receptor

Interaction

Lock and key mechanism


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Antagonist Receptor

Antagonist-Receptor

ComplexDENIED!

CompetitiveInhibition


DOR 101 Pharmacology 1st and 2nd

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