PNUR 1104 Lecture 1 Overview_sound-1

7/30/2019 PNUR 1104 Lecture 1 Overview_sound-1

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PNUR 1104Pharmacology for HealthProfessionals

Overview of Pharmacology


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Overview of Pharmacology

PNUR 1104 Online

Pharmacology for Health

Professionals


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Objectives

Define selected key pharmacologicalterms

Identify common sources of drugs

Discuss how drugs are classified

Differentiate between chemical,generic, and trade names of drugs

Identify sources of drug information


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Objectives

Summarize the standards and lawswhich govern drug use.

Discuss the categories of controlledsubstances.

Discuss the role of the Food and DrugAdministration.


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Definition of Terms

Pharmacology

Drug

Drug therapy

Medication

Local effects

Systemic effects

Prototype

Drug classification

Therapeuticclassification

Pharmacologic orchemicalclassification

Chemical name

Generic name


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Definition of Terms

Trade or brand name

Bioequivalent

Prescription drugs Non-prescription or over-the-counter

(OTC) drugs

Controlled substances


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Sources of Drugs

Historically derived from plants

Synthetic drugs manufactured in labs

Semisynthetic drugs are naturallyoccurring substances that have beenchemically altered.

Biotechnology ( recombinantdeoxyribonucleic acid technology)


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Drug Classification

Similar drugs are grouped togetherfor purpose of study & for ease ofprescribing.

Drugs are classified according to theireffects on particular body systems,their therapeutic uses & their

chemical characteristics.


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Drug Classification

Pharmacologic classification

Therapeutic classification

Chemical classification Other classifications: Body system,

General use, Family, Primary action,and indication.


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Drug Classification

Example: Morphine is a CNS

depressant, narcotic analgesic &opiate as well as the prototype ofnarcotic analgesics.


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Uses of Drugs

Therapeutic uses

Palliative uses

Prophylactic uses Diagnostic uses

Replacement uses


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Drug Nomenclature

Chemical name

Generic or nonproprietary name

Trade (Brand) or proprietary name


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Sources of Drug Information

Pharmacologytextbooks

Drug reference

books: Physiciansdesk reference(PDR), Nursingdrug reference

books

Journal articles &newsletters

Internet sites

Poison ControlCenters

Clinicians andPharmacists


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Laws and Standards

State laws regulate some aspects ofdrug use, sale and distribution, butfederal laws regulate most majoraspects. Food and Drug Administration (FDA)

Public Health Service

Federal Trade Commission


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Laws and Standards

Pure Food & DrugAct of 1906

Sherley

Amendment of1912

Harrison NarcoticAct of 1914

Food, Drug &Cosmetic Act of1938

Amendment of1945

Durham-HumphreyAmendment of

1952


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Laws and Standards

Kefauver-HarrisAmendment of1962

ComprehensiveDrug AbusePrevention &Control Act of1970 (ControlledSubstance Act)

Drug RegulationReform Act of1978

Orphan Drug Actof 1983

FDA ModernizationAct of 1997

Drug Price &Patent TermRestoration


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Categories of ControlledSubstances

Schedule I: not approved for medical use,have high abuse potential

Schedule II: used medically & have high

abuse potential Schedule III: less potential for abuse

Schedule IV: some potential for abuse

Schedule V: contain moderate amounts ofcontrolled substances


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FDA Pregnancy Categories

Category A: Remote risk of fetalharm

Category B: Slightly More risk than A

Category C: Greater risk than B

Category D: Proven risk of fetal

harm Category X: Proven risk of fetal

harm


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Drug Approval Process

FDA is responsible for approving allnew drugs and certain other aspectsof drug use - reviews all researchstudies related to drugs. Does not dotesting itself.

Newly developed drugs have to be

extensively tested.


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Testing Process

Begins with animal studies -reviewed by the FDA for approval togo to next step.

Next is clinical trials in humans:

Phase I, Phase II, Phase III, Phase IV(FDA evaluates data)

Double-blind, placebo controlled,crossover studies, control studies andsubject matching


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Cellular physiology

Because all body functions, diseaseprocesses, and most drug interactionstake place at the cellular level, wemust understand cellular physiology.


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Cellular physiology

Each body cell has the capacity tofunction and respond to injury.

Although cells differ in various tissuesaccording to location & function, theyhave common characteristics: Exchange materials with their environment

Communicate with each other


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Characteristics of InflammatoryResponse

The characteristics of theinflammatory response can be localor systemic reactions. Thesereactions may vary according to thecause and/or extent of the injury.


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LOCAL REACTION:

Erythema or redness

Heat

Edema or swelling

Pain

Purulent discharge


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SYSTEMIC REACTION:

Leukocytosis ( increased WBCs)

Increased erythrocyte sedimentation rate(ESR)

Fever

Headache

Loss of appetite Lethargy

Weakness


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Questions?


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Basic Concepts andProcesses


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Objectives

Identify factors that decreaseabsorption of an oral drug.

Identify mechanisms of drugmovement in the body.

Discuss absorption, distribution,metabolism, and excretion of drugs in

the body.


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Objectives

Discuss the main elements of thereceptor theory of drug action.

Discuss variables that effect drugactions in the body.

Identify adverse effects of drugs onthe body.


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Definition of Terms

Pharmacotherapeutics

Pharmacokinetics

Passive diffusion

Facilitated diffusion

Active transport

Absorption

Distribution

Metabolism

Excretion

Serum half-life

Pharmacodynamics

Dose

Dosage

Toxic dose


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Definition of Terms

Lethal dose

Route ofadministration

Drug-dietinteraction

drug-druginteraction

Additive effects

Synergism

Interference

Displacement

Agonist

Antagonist

Pharmacogenetics

Pharmaco-anthropology


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Definition of Terms

Adverse effects orside effects

Therapeutic effects

Toxic effects

Hepatotoxicity

Nephrotoxicity

Ototoxicity

Hypersensitivity orallergic reaction

Drug fever

Idiosyncrasy

Anaphylactic

reaction Drug dependence


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Definition of Terms

Carcinogenicity

Teratogenicity

Tolerance

Cross tolerance

Metabolite

Drug action

Onset of action

Peak of action

Duration of action

Therapeutic blood

level

Peak blood level

Toxic blood level

Indication(s) Contraindications


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Definition of Terms

Precautions

Incompatibility

Loading dose

Maintenance dose

Cumulative effects


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Mechanisms of Drug Movement

To act on body cells, drugs given forsystemic effects must reach adequateconcentrations in blood & other tissue fluids

surrounding the cells. Thus, they mustenter the body & be circulated in thebloodstream. After they act on cells, theymust be eliminated from the body, as are

other chemical bodies.


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Passive diffusion: higher to lower

Facilitated diffusion: drug moleculescombine with a carrier substance

Active transport: lower to higher


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Drug movement & therefore drugaction are affected by a drugs abilityto cross cell membranes. Cell

membranes are complex structurescomposed of lipid & protein:

Lipid soluble drugs

Water soluble drugs


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Pharmacokinetics

Absorption:

Dosage form

Route of

administration GI function

Increased gastricemptying

Food in thestomach

SQ or IM injections

IV therapy

Skin absorption

Mucous membrane

Lungs


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Pharmacokinetics

Distribution: involves thetransport of drug molecules withinthe body. Carried to sites of action, metabolism &

excretion Depends largely on adequacy of circulation

Protein binding

Only free or unbound portion of drug acts onbody cells

Drug distribution in CNS is unique

Drug distribution during pregnancy &lactation is unique


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Pharmacokinetics

Metabolism: method by which drugsare inactivated or biotransformed bythe body. Changed into one or more inactive metabolites

& excreted

Kidney can only excrete water solublesubstances

Most drugs are metabolized by enzymes in theliver


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Pharmacokinetics

Metabolism:

Enzyme induction

Enzyme inhibition

Rate of metabolism

Oral drugs absorbed in the GI tract thatare extensively metabolized in the liver

reduce systemic circulation


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Pharmacokinetics

Excretion: refers to elimination of adrug from the body.

Requires adequate functioning of the

circulatory system & organs of excretion

Most drugs are excreted by the kidneys Bile

Feces

Lungs

Skin


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Pharmacokinetics

Serum half-life: also called elimination half-time, isthe time required for the serum concentration of adrug to decrease by 50%.

Determined primarily by drugs rates ofmetabolism & excretion

Short half life require more frequentadministration

4-5 half lives are required to achieve steady-state concentrations

Eliminated gradually over several half-lives


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Pharmacodynamics

Receptor theory of drug action

Specific receptors: enzymes, proteins,nucleic acids

Changes in cellular metabolism

Changes permeability of cell membrane

Modifies physiologic process of cell

Receptors vary in type, location &number


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Pharmacodynamics

When drug molecules chemically bindwith cell receptors, pharmacologiceffects are agonism or antagonism:

Agonists

Antagonists


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Pharmacodynamics

Nonreceptor drug actions: relativelyfew drugs act by other mechanisms.

Antacids

Osmotic diuretics

Structurally similar to nutrients

Metal chelating agents


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Variables That Affect DrugActions

Drug related variables:

Dosage

Route of administration

Drug-diet interaction

Drug-drug interactions


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Drug-Drug Interactions

Additive effects

Synergism orpotentiation

Interference Displacement

Specific antidote

Decreasedintestinal

absorption due tobinding

activation ofenzymes

Increasedexcretion


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Client Related Variables

Age

Body weight

Genetic &ethniccharacteristics

Gender

Pathologicconditions

Psychologicalconsiderations


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AGE

Children

Pregnancy

Newborns

Older infants

1 -12 year olds

After age 12

Older adults (65 & over)


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Body Weight

Larger than average person requiresmore than average person.

Nurse may have to calculate by mgper kg of weight.

Fat cells may store drug and releaselater.


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Gender

Altered responses to drugs have beendemonstrated possibly due tohormonal influence.


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Pathologic Conditions

Disorders may cause an alteration inthe pharmacokinetic process:

Hypotension, shock, low plasma

Vomiting, diarrhea, malabsorption

Liver or kidney disease

Malnutrition


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Psychological Considerations

Placebo response

Attitude and expectations

Compliance


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Adverse Effects of Drugs

All drugs can produce adverse effects

May be common, rare, mild or severe

May occur with usual therapeuticdoses of drugs and are often calledside effects.


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Adverse Effects of Drugs

CNS effects

GI effects

Hematologic effects

Hepatotoxicity

Nephrotoxicity

HypersensitivityDrug fever

Idiosyncrasy

Drug dependence Carcinogenicity

Teratogenicity


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Tolerance and Cross-Tolerance

Drug tolerance

Cross-tolerance

Tachyphylaxis


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Questions?


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Nursing Process in DrugTherapy


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Objectives

Discuss general principles of drugtherapy.

Identify information to be included ina medication history.

Identify the Food and DrugAdministration Pregnancy Categories

for drugs.


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Introduction

Drug therapy is one of the manynursing responsibilities in client care.To fulfill this responsibility the nurse

must be: Be knowledgeable about pharmacology

Monitor responses to drug therapy

Teach clients and families about drugs


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Using Prototypes Approach toStudy Pharmacology

Concentrate on therapeuticclassifications, groups of drugs &prototypes of those groups.

Know major characteristics for agroup.

Set guidelines for effective study

L l R ibiliti f th


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Legal Responsibilities of theNurse

Nurses are legally empowered to givemedications ordered by licensedphysicians and dentists (in all states

but GA, NPs).

When giving medications, the nurse islegally responsible for safe and

accurate administration (5 Rights).

Legal Responsibilities of the


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The nurse is expected to have sufficient drugknowledge to recognize & question erroneous orders.

The nurse is responsible for storing narcotics & othercontrolled substances in locked containers, administeronly to people for whom they are prescribed,recording each dose given on the appropriate form &on MAR, counting the amount of each drug at the endof shift and reporting any discrepancies.

Legal Responsibilities of the


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The nurse is expected to observeclients for therapeutic & adverseeffects, as well as, teach clients safe

and effective self-administration ofdrugs when indicated.

Medication errors can be eliminated

by following safe practices &guidelines.


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Applying the Nursing Process

The nursing process is a systematic way ofgathering information and using thatinformation to plan, provide, and toevaluate client care and outcomesrequired for drug therapy.

AssessmentNursing diagnosisPlanning/goals

Nursing interventionsEvaluation

General Principles of Drug


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General Principles of DrugTherapy

The goal of drug therapy

Benefits should outweigh the adverseeffects

Drug therapy should be individualized

Drug costs and effects on quality oflife should be considered

General Drug Selection &


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General Drug Selection &Dosage Considerations

Use as few drugs in as few doses aspossible

Individual drugs allow greater flexibility &

individualization of dosage than fixed The least amount of the least potent drug

that will yield therapeutic benefit should begiven to decrease adverse effects.

General Drug Selection &


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General Drug Selection &Dosage Considerations

Recommended dosages are listed inamounts likely to be effective for mostpeople, but are only guidelines to beinterpreted according to client

characteristics. Treatment with a particular drug can bestarted rapidly or slowly.

Different salts of the same drug rarelydiffer pharmacologically.


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Drug Therapy in Children

Special considerations Pharmacokinetics less predictable Fewer studies/ less research Neonates immature kidney/liver function Most meds given to adults are given to

children as well Use general principles, techniques of drug

administration as with adults but with

additional guidelines

Additional Guidelines for Drug Administration to


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Additional Guidelines for Drug Administration toChildren

Drug therapy is guided by childs age,weight, and level of growth anddevelopment.

Choices of drug is often restricted.

Safe therapeutic dosage ranges are lesswell defined for children.

Use the oral route of administration whenpossible.

Use thigh muscle for IM injections. Child-proof containers.


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Drug Therapy for Older Adults

Adverse effects are especially likely tooccur due to physiological changesassociated with aging, pathologic changesdue to disease processes, multiple drug

therapy for acute and chronic disorders,impaired memory & cognition & difficultyin complying with medication orders.

The overall goal may be care instead ofcure with efforts to prevent or controlsymptoms & maintain ability of ADLfunction .


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Additional Guidelines for Drug Therapy in theOlder Adult

Physiologic age (organ function) is moreimportant than chronological age.

S&S attributed to age may be caused bydrug therapy.

Medications should be taken only whennecessary.

Review current meds before prescribingnew medications.


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Additional Guidelines for Drug Therapyin the Older Adult

Give smallest number of effective drugs.

Give for shortest effective time needed andreassess periodically.

Smallest number of doses necessaryprescribed to least disrupt routine.

Start slow, go slow.

Use non-drug measures as much as

possible.


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Additional Guidelines for Drug Therapyin the Older Adult

Long term drug therapy - home safety/effectiveness guidelines: Label containers/Magnifying glass Use easy open containers

Special devices & methods Enlist help of family members Observe for changes in S&S related to

adverse drug reactions as opposed to

aging process


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Questions?

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PNUR 1104 Lecture 1 Overview_sound-1