unit 1 introduction to pharmacology. pharmacology study of drugs and their action on the living body

UNIT 1 INTRODUCTION TO PHARMACOLOGY

Study of drugs and their action on the

living body

Medicinal agent that modifies body function

Used:To prevent ds. or pregnancyTo aid in dx or txTo restore or maintain functions

DRUG SOURCESAnimalsPlantsVitaminsMineralsSynthetics

SourcesAnimals

InsulinAdrenalinCortisoneThyroidHormones

SourcesPlants

Foxglove PoppyKelp MoldRoots BarkSeeds

SyntheticsLess expensive, more pure

NURSE’S ROLEKnowledge of:

Drug Action What is the expected responseTherapeutic Effect

Will this med achieve it’s goalPossible Adverse EffectsPatient Teaching

With every medThere is no excuse for administering a drug

without full knowledge

ASSESSMENT

ASSESSMENTOBJECTIVE

Physical assessment including: V.S. Weight Skin color

Diagnostic tests Drug levels in body (Dilantin, Dig) PT/INR LABS (BS/K)

SUBJECTIVE Allergy history (What kind of reaction) Complaints (?Pain)

PLANNING

PLANNINGSorting and analyzing the data to develop the plan of care and goalsWhat are you going to do based on your findings?

Planning pt / family teachingWhat needs to be taught?, When? Do you need handouts?

IMPLEMENTATION

IMPLEMENTATIONThis is the third step in the nursing process and is when we actually take actions that we planned.

This is execution of nursing actions

IMPLEMENTATIONPreparing and administering drugs

Always follow the six rightsAssessment of V.S. prior to administration

Actually check the VS, BSPatient teachingActually doing the teaching

EVALUATION

EVALUATIONHow the pt is responding to the intervention

Was goal met?

Reassessment of V.S., Pain level, etc.

Did BP respond?Did pain decrease?

PATIENT TEACHINGMost dramatic change in recent years

Patient has a right to know what med was given, they have right to refuse, and they have the right to generics

One of our most important rolesProvide written material, reinforce key points, document

DRUG LEGISLATION1906 Federal, Food, Drug and

Cosmetic Act

Began federal regulation Established safety guidelines;

required labeling, prohibited false claims and regulated advertising

National standards for drugs – USP (United States Pharmacopeia)Purity / Safety Concerns

1914 Harrison Narcotic ActFirst narcotic control

1938 – added FDA to enforce laws

1945, 1952, 1962 Amendments to Federal Food, Drug and Cosmetic Act

FDAFDA - Food and Drug Administration

part of Dept. Health and Human services

Federal agency to enforce federal drug laws including:Purity, labeling, testing, dispensing, safety,

advertisementFDA determines safety of drugs before

marketing, monitors development of new drugs

1970 CONTROLLED SUBSTANCE ACTStrict controls on manufacture and distribution of habit-forming drugs

Established 5 schedules of habit-forming drugs

Required gov’t programs to promote prevention & tx of drug dependence

Schedule 1 not accepted in US

Schedule I DrugsSchedule I Drugs

Schedule I drugs have a high tendency for abuse and have no accepted medical use. This schedule includes drugs such as Marijuana, Heroin, Ecstasy, LSD, and GHB. Recent activists have tried to change the schedule for Marijuana citing the possible medical benefits of the drug. Pharmacies do not sell Schedule I drugs, and they are not available with a prescription by physician.

Schedule II DrugsSchedule II Drugs

Schedule II drugs have a high tendency for abuse, may have an accepted medical use, and can produce dependency or addiction with chronic use. This schedule includes examples such as Cocaine, Opium, Morphine, Fentanyl, Amphetamines, and Methamphetamines. Schedule II drugs may be available with a prescription by a physician, but not all pharmacies may carry them. These drugs require more stringent records and storage procedures than drugs in Schedules III and IV.

Schedule III DrugsSchedule III Drugs

Schedule III drugs have less potential for abuse or addiction than drugs in the first two schedules and have a currently accepted medical use. Examples of Schedule III drugs include Anabolic steroids, Codeine, Ketamine, Hydrocodone with Aspirin, and Hydrocodone with Acetaminophen. Schedule III drugs may be available with a prescription, but not all pharmacies may carry them.

Schedule IV DrugsSchedule IV Drugs

Schedule IV drugs have a low potential for abuse, have a currently accepted medical use, has a low chance for addiction or limited addictive properties. Examples of Schedule IV drugs include Valium, Xanax, Phenobarbital, and Rohypnol (commonly known as the "date rape" drug). These drugs may be available with a prescription, but not all pharmacies may carry them.

Schedule V DrugsSchedule V Drugs

Schedule V drugs have a lower chance of abuse than Schedule IV drugs, have a currently accepted medical use in the US, and lesser chance or side effects of dependence compared to Schedule IV drugs.  This schedule includes such drugs as cough suppressants with Codeine. Schedule V drugs are regulated but generally do not require a prescription.

Illegal to possess controlled substances without rx

Formed Drug Enforcement Agency (DEA) to enforce

DRUG NAMESGeneric Name

May be used by other manufacturers, less costly, not capitalized

Trade / Brand NameUsually shortEasy to spellCapitalizedName given by manufacturer followed with

“R”Copyright name (Tylenol, Advil, Demerol)

DRUG REFERENCESUSP / NF (FDA)United States Pharmacopeia – standard for drugs

updated every 5 years with formulas & standards for preparation & dispensation of drugs

National Formulary – drugs of established usefulness

U.S. DISPENSATORY Publication of description and composition of medicines

PDR – published annually Physicians Desk Reference – divided into color coded

sections

DRUG REFERENCES

NURSING DRUG HANDBOOKSHandbooks: Davis Drug Guide, Saunders

etc.

FACTS AND COMPARISONS listed by body system

ALSO – each HCF has it’s own ‘hospital’ formulary – cannot carry every drug; may see substitutions

PHARMACOKINETICSUse of drug by body Process that affect drug from time it enters the body to time it leaves

Divided into 4 phasesAbsorptionDistributionBiotransformationExcretion

ABSORPTIONPassage of drug from site of entry to bloodstream

What is the most common site of entry?

What factors affect absorption?

Absorption FactorsRoute of administration & conditions at

absorptive site Drug form – enteric coated; sustained

release; liquid Gastric emptying & gastric motility Timing – presence of food, other drugs – esp.

antacids

DISTRIBUTIONProgress or transportation from bloodstream to particular

site of action (receptor sites)Receptor sites or target tissue where drug chemically

bonds to cells

What factors affect distribution?Circulation, cardiac output, blood supply to site of drug

actionBinding of drugs to Plasma Protein Albumin & Tissue

bindingLevel of plasma proteins (albumin)For PO drugs, amt of drug metabolized by liver before

reaching systemic circulationBlood – Brain Barrier prevents many drugs from entering

CNS

BIOTRANSFORMATIONMetabolismDegradation or breakdown of drug for excretion

Process by which drug is detoxified or inactivated

What factors affect biotransformation?

BiotransformationFactors: Condition of liver – most drugs

detoxified by liver – need to check LFT’s“First Pass” thru liver is why oral drugs are

given in higher dosesChemicals or drugs that stimulate production

of transforming enzymes = decreased drug effect

Chemicals or drugs that decrease production of transforming enzymes = increased drug effect, cumulative effect, increased adverse reactions

EXCRETIONElimination of the drug from the body

What factors affect excretion? Kidney – condition of kidney as this is the main excretory organ

Other excretory – respiration, perspiration, defecation

BLOOD LEVELSAmount of drug in circulating fluid is often measured

Drug half life – amount of time for serum concentration to decrease by 50%

Commonly done with Antibiotics, Lanoxin, AED’s

Medication Actions and Interactions

LOCAL – affects only area drug is placed, not absorbed into blood stream

SYSTEMIC – absorbed into bloodstream

TERMSTherapeutic EffectAgonistAntagonistAdditiveSynergistic / Potentiating

Therapeutic: desired or intended effectAgonist: drug that produces a response, stimulates

a responseAntagonist: drug that blocks the action of another

drug, opposing effect sometimes desired – Narcansometimes undesired – Antibiotics & BCP’s

Additive: 2 drugs with similar actions sum of their effects

1+1=2 (alcohol + sedatives)Synergistic: 2 drugs with different actions

produce greater effects 1+1=3 (Codeine + ASA)

IncompatibilityIdiosyncraticAnaphylactic (Allergic)CumulativeAdverse Effect / Side Effect

Incompatibility: drugs that do not combine chemically with other drugs, don’t mix, compatibility charts on nursing units

Idiosyncratic: unusual or unexpected + highly individualized

Anaphylactic: Hypersensitivity; antigen/antibody reaction – can be severe, life threatening Be careful to check allergies

Cumulative: drugs that build up in the body, may be d/t increased dose, poor circulation, metabolism or excretion

Adverse Effect: undesired action – usually classified by body system

are considered adverse but can be helpful in some situations i.e. Pt has angina& HTN, Nitrates vasodilate + also lowers B

P

DRUG FORMSLiquids

Oral, parenteral, topical, instillation

SolidsTablets, caplets, capsules, powder, zydis

Liquids:Parenteral: other than GI ( IM, SC, ID, IV,

inhalation)Instillation: eyedrops, eardrops, other

examples

Solids:Powder: often mixed with liquids (diluent)Zydis: on tongue + dissolves

SemisolidsSuppositoriesOintments, Pastes

InhalersMetered dose decreases systemic effects

Transdermals

DRUG DOSAGEFactors to be considered:AgeWeightPhysical HealthPsychological Status

More FactorsEnvironmental Temp.GenderAmount of food in stomach

Dosage forms

DOSAGE CONSIDERATIONSTherapeutic doseMinimal doseLoading doseMaximal doseToxic doseLethal dose

MEDICATION ORDERSWho can write a prescription?

Written ordersVerbal ordersStanding ordersStat orders

PARTS OF A PRESCRIPTIONPt NameDate, TimeName of DrugDose of DrugTime / FrequencyMethod / RouteHC Provider SignatureDOBSpecial Instructions