Introduction to Drug Therapy

7/31/2019 Introduction to Drug Therapy

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Nursing 3703Nursing 3703

Pharmacology in NursingPharmacology in Nursing

Introduction to Drug TherapyIntroduction to Drug Therapy

Linda SelfLinda Self


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Grouping of DrugsGrouping of Drugs

Names may reflect the conditions for whichNames may reflect the conditions for which

they are used (e.g. antidepressants)they are used (e.g. antidepressants)

May reflect their chemical characteristicsMay reflect their chemical characteristics(benzodiazepines)(benzodiazepines)

May reflect the effects on body systemsMay reflect the effects on body systems

(central nervous system depressants)(central nervous system depressants)


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Prototype DrugsPrototype Drugs

Individual drugs that represent groups ofIndividual drugs that represent groups of

drugs are calleddrugs are called PrototypesPrototypes

May be the first drugs of this group to beMay be the first drugs of this group to bedeveloped (e.g., penicillin for antibiotics,developed (e.g., penicillin for antibiotics,

morphine for opioid analgesics)morphine for opioid analgesics)


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Drug NamesDrug Names

Generic Name is related to the chemicalGeneric Name is related to the chemical

name and is independent of thename and is independent of the

manufacturer (e.g., sertraline)manufacturer (e.g., sertraline)

Trade name is designated and patented byTrade name is designated and patented by

the manufacturer (e.g., Zoloft)the manufacturer (e.g., Zoloft)


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American Drug Laws andAmerican Drug Laws and

AmendmentsAmendments

1938 Food, Drug and Cosmetic Act required1938 Food, Drug and Cosmetic Act required

proof of safety, authorized factoryproof of safety, authorized factory

inspections, established penalties forinspections, established penalties for

fraudulent claimsfraudulent claims

1952 Durham-Humphrey Amendment1952 Durham-Humphrey Amendment

designated drugs that must be prescribeddesignated drugs that must be prescribed

by a physician and dispensed by aby a physician and dispensed by a

pharmacist (e.g., controlled substances,pharmacist (e.g., controlled substances,

etc.)etc.)


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American Drug Laws cont.American Drug Laws cont.

1970 Comprehensive Drug Abuse1970 Comprehensive Drug Abuse

Prevention and Control Act; Title II,Prevention and Control Act; Title II,

Controlled Substances ActControlled Substances Act

Categorized according to potential for abuseCategorized according to potential for abuse

Regulated distribution of narcotics and otherRegulated distribution of narcotics and other

drugs of abusedrugs of abuse DEA charged w/enforcing the ControlledDEA charged w/enforcing the Controlled

Substances ActSubstances Act


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Categories of Controlled SubstancesCategories of Controlled Substances

Schedule Inot approved for medical useSchedule Inot approved for medical use

and have high abuse potentials; LSD,and have high abuse potentials; LSD,

heroin, peyote, ecstasy (3,4 methyenedioxy-heroin, peyote, ecstasy (3,4 methyenedioxy-

methamphetamine)methamphetamine)

Schedule IIused medically. High abuseSchedule IIused medically. High abuse

potential (methadone, meperidine, cocaine,potential (methadone, meperidine, cocaine,

pentobarbital, Tylox)pentobarbital, Tylox)


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Categories of Controlled SubstancesCategories of Controlled Substances

continuedcontinued

Schedule III-less potential for abuse than ISchedule III-less potential for abuse than Iand II but may lead to psychological orand II but may lead to psychological orphysical dependence (Vicodin, Tylenol withphysical dependence (Vicodin, Tylenol with

codeine)codeine) Schedule IV-drugs have some potential forSchedule IV-drugs have some potential for

abuse (Valium, Dalmane, Klonopin)abuse (Valium, Dalmane, Klonopin)

Schedule V-contain moderate amounts ofSchedule V-contain moderate amounts ofcontrolled substances. An example iscontrolled substances. An example isLomotil (atropine and diphenoxylate)Lomotil (atropine and diphenoxylate)


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Pregnancy CategoriesPregnancy Categories

Cat. A-studies in pregnant women failed toCat. A-studies in pregnant women failed to

show risk to the fetusshow risk to the fetus

Cat. B- animal studies have failed to show aCat. B- animal studies have failed to show arisk to the fetus but there are no adequaterisk to the fetus but there are no adequate

studies in womenstudies in women

Cat. C-animal studies have shown anCat. C-animal studies have shown anadverse effect on the fetus, no adequateadverse effect on the fetus, no adequate

human studies, benefits may outweigh riskshuman studies, benefits may outweigh risks


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Pregnancy Categories cont.Pregnancy Categories cont.

Cat. D-positive evidence of human fetal riskCat. D-positive evidence of human fetal risk

Cat. X-animal or human studies have shownCat. X-animal or human studies have shown

fetal abnormalities or toxicityfetal abnormalities or toxicity


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PharmacokineticsPharmacokinetics

Involves drug movement through the bodyInvolves drug movement through the body

to reach sites of action, metabolism, andto reach sites of action, metabolism, and

excretionexcretion

Specific processes are absorption,Specific processes are absorption,

distribution, metabolism and excretiondistribution, metabolism and excretion


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Pharmacokinetics-Drug TransportPharmacokinetics-Drug Transport

PathwaysPathways

Three main pathways of drug movementThree main pathways of drug movementacross cell membrancesacross cell membrances

1.1. Most common isMost common is direct penetrationdirect penetration by lipidby lipidsoluble drugssoluble drugs

2.2. 22ndnd pathway involves passage throughpathway involves passage throughprotein channelsprotein channels. Gates open and close. Gates open and close

either by voltage gating or by assist ofeither by voltage gating or by assist ofchemical substances (Na+ and K+ ionschemical substances (Na+ and K+ ionsaffecting some cardiac drugs)affecting some cardiac drugs)


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Drug Transport Pathways cont.Drug Transport Pathways cont.

3. 33. 3rdrd is byis by carrier proteinscarrier proteins that transportthat transport

molecules from one side of the cellmolecules from one side of the cell

membrane to the other. An example wouldmembrane to the other. An example would

be oral drugs that carry hormones to theirbe oral drugs that carry hormones to their

sites of actionsites of action

(see text for details)(see text for details)


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PharmacokineticsPharmacokinetics

Absorption-process that occurs from theAbsorption-process that occurs from thetime a drug enters the body to the time ittime a drug enters the body to the time itenters the bloodstream to be circulatedenters the bloodstream to be circulated

Factors affecting absorption include: dosageFactors affecting absorption include: dosageform, route of administration, blood flow toform, route of administration, blood flow tothe site of administration, gastrointestinalthe site of administration, gastrointestinal

function, presence of food or other drugsfunction, presence of food or other drugs For many medications, food in the stomachFor many medications, food in the stomach

slows absorptionslows absorption


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BioavailabilityBioavailability

Is the portion of a dose that reaches theIs the portion of a dose that reaches the

systemic circulation and is available to actsystemic circulation and is available to act

on body cellson body cells

IV administration is 100% bioavailableIV administration is 100% bioavailable

Subcutaneous administrations has moreSubcutaneous administrations has more

rapid absorption than does the oral routerapid absorption than does the oral route Mucous membranes allow for rapid andMucous membranes allow for rapid and

direct absorption into the bloodstreamdirect absorption into the bloodstream


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DistributionDistribution

Involves the transport of drug moleculesInvolves the transport of drug molecules

within the bodywithin the body

After the drug is absorbed into theAfter the drug is absorbed into thebloodstream, it is carried by the blood orbloodstream, it is carried by the blood or

tissue fluids to its sites of pharmacologictissue fluids to its sites of pharmacologic

action, metabolism and excretionaction, metabolism and excretion

Protein binding is an important factor in drugProtein binding is an important factor in drug

distributiondistribution


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Distribution cont.Distribution cont.

Drug distribution into the CNS is limited becauseDrug distribution into the CNS is limited because

of the blood-brain barrierof the blood-brain barrier

Blood-brain barrier is composed of capillaries withBlood-brain barrier is composed of capillaries with

tight walls which limits movement of drugtight walls which limits movement of drugmolecules into brain tissuemolecules into brain tissue

Only drugs that are lipid soluble or have aOnly drugs that are lipid soluble or have a

transport system can cross the blood-brain barriertransport system can cross the blood-brain barrierand reach therapeutic concentrations in brainand reach therapeutic concentrations in brain

tissuetissue


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Distribution cont.Distribution cont.

Drug distribution during pregancy andDrug distribution during pregancy and

lactation is unique as most drugs cross thelactation is unique as most drugs cross the

placenta or in the case of lactation, passplacenta or in the case of lactation, pass

into breastmilkinto breastmilk


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Protein bindingProtein binding

Most drugs form a compound with plasmaMost drugs form a compound with plasma

proteins, mainly albumin, which act as carriersproteins, mainly albumin, which act as carriers

Only the free or unbound portion of a drug acts onOnly the free or unbound portion of a drug acts on

body cellsbody cells

As unbound drug acts on cells, the decrease inAs unbound drug acts on cells, the decrease in

plasma drug level causes some of the bound drugplasma drug level causes some of the bound drug

to be releasedto be released Protein binding allows a part of a drug dose to beProtein binding allows a part of a drug dose to be

stored and released as neededstored and released as needed


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MetabolismMetabolism

Method by which drugs are inactivated orMethod by which drugs are inactivated or

biotransformed by the bodybiotransformed by the body

Some drugs yield metabolites that are alsoSome drugs yield metabolites that are alsoactive and exert effects on the body untilactive and exert effects on the body until

they are excreted (normeperidine)they are excreted (normeperidine)

Most drugs are lipid soluble which aids theirMost drugs are lipid soluble which aids theirpassage across the cell membranepassage across the cell membrane


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Metabolism cont.Metabolism cont.

Excretion usually is by kidneys. Need to beExcretion usually is by kidneys. Need to be

water soluble for this to occur. Thus, onewater soluble for this to occur. Thus, one

function of metabolism is to convert fatfunction of metabolism is to convert fat

soluble medications to water soluble ones.soluble medications to water soluble ones.

Hepatic drug metabolism or clearance is aHepatic drug metabolism or clearance is a

major mechanism for terminating drugmajor mechanism for terminating drug

action and eliminating drug molecules fromaction and eliminating drug molecules from

the bodythe body


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Metabolism cont.Metabolism cont.

Most drugs are metabolized by theMost drugs are metabolized by the

cytochrome P450 enzymes in the livercytochrome P450 enzymes in the liver

Liver contains complex system of enzymes,Liver contains complex system of enzymes,three of which are key in the metabolism ofthree of which are key in the metabolism of

medications/drugsmedications/drugs


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Cytochrome p450Cytochrome p450

CYP enzymes catalyze the chemical reactionsCYP enzymes catalyze the chemical reactions

which ultimately metabolize the medicationswhich ultimately metabolize the medications

With chronic administration (greater than 1-3With chronic administration (greater than 1-3

weeks), some drugs stimulate hepatocytes toweeks), some drugs stimulate hepatocytes toproduce larger amounts of drug metabolizingproduce larger amounts of drug metabolizing

enzymes (inducers). Enzyme induction acceleratesenzymes (inducers). Enzyme induction accelerates

drug metabolism. Result is that larger doses of thedrug metabolism. Result is that larger doses of the

drug may be need for therapeutic effects.drug may be need for therapeutic effects.


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Cytochrome p450Cytochrome p450

Enzyme inhibition may occur with concurrentEnzyme inhibition may occur with concurrent

administration of two or more drugs that competeadministration of two or more drugs that compete

for the same metabolizing enzymes (e.g., Dilantin,for the same metabolizing enzymes (e.g., Dilantin,

EES, Tagamet)EES, Tagamet) Oral meds are generally absorbed by the GI tractOral meds are generally absorbed by the GI tract

and carried to the liver. Drug may undergoand carried to the liver. Drug may undergo

extensive metabolism leaving little for systemicextensive metabolism leaving little for systemic

use. This is called theuse. This is called the first pass effect.first pass effect.


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ExcretionExcretion

Refers to the elimination of a drug from theRefers to the elimination of a drug from the

bodybody

Most are excreted by the kidneys althoughMost are excreted by the kidneys althoughsome are excreted in the bile then the fecessome are excreted in the bile then the feces


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Serum Drug LevelsSerum Drug Levels

Lab measurement of the amount of a drugLab measurement of the amount of a drugin the blood at a particular timein the blood at a particular time

Minimum effective concentration (MEC)-Minimum effective concentration (MEC)-

must be present before a drug exerts itsmust be present before a drug exerts itspharmacologic action on body cellspharmacologic action on body cells

Duration of action-Duration of action-time during which serumtime during which serum

drug levels are at or above the MEC (maydrug levels are at or above the MEC (maymeasure serum drug levels when the drugsmeasure serum drug levels when the drugshave a low therapeutic index)have a low therapeutic index)


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Pharmacodynamics--ReceptorsPharmacodynamics--Receptors

Involves drug actions on target cells and theInvolves drug actions on target cells and the

resulting alterations in cellular biochemicalresulting alterations in cellular biochemical

reactionsreactions

Most drugs chemically bind with receptors atMost drugs chemically bind with receptors at

the cellular levelthe cellular level

Drug-receptor complex initiatesDrug-receptor complex initiates

physiochemical reactions that stimulate orphysiochemical reactions that stimulate or

inhibit cellular functionsinhibit cellular functions


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Pharmacodynamics-receptorsPharmacodynamics-receptors

Receptors vary in type, location, numberReceptors vary in type, location, number

and functional capacityand functional capacity

When drug molecules chemically bind withWhen drug molecules chemically bind withcell receptors, pharmacologic effects resultcell receptors, pharmacologic effects result

from agonism or antagonismfrom agonism or antagonism


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Pharmacodynamics-receptorsPharmacodynamics-receptors

Agonists-Agonists-are drugs that produce effects similar toare drugs that produce effects similar to

those produced by naturally occurring hormones,those produced by naturally occurring hormones,

neurotransmitters and others. Agonists mayneurotransmitters and others. Agonists may

accelerate or slow normal cellular processesaccelerate or slow normal cellular processesdepending on the type of receptor activated.depending on the type of receptor activated.

AntagonistsAntagonistsdrugsdrugsthat inhibit cell function bythat inhibit cell function by

occupying receptor sites.occupying receptor sites.

Not all drugs act on receptors. Examples include:Not all drugs act on receptors. Examples include:

antacids, osmotic diuretics, chelators.antacids, osmotic diuretics, chelators.


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Variables that affect drug actionsVariables that affect drug actions

DosageDosage

RouteRoute

Drug-diet interactions. Food may slowDrug-diet interactions. Food may slowabsorption or foods may actually interactabsorption or foods may actually interact

with certain medications (tyramine and MAOwith certain medications (tyramine and MAO

inhibitors; tetracycline and milk products;inhibitors; tetracycline and milk products;

ingestion when taking certainingestion when taking certain

antihypertensive medications)antihypertensive medications)


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Variables affecting drug actionsVariables affecting drug actions

Drug-drug interations-additive effects suchDrug-drug interations-additive effects such

as seen with sedatives and ethanol.as seen with sedatives and ethanol.

Synergism as seen with acetaminophen andSynergism as seen with acetaminophen and

codeine.codeine.

Antidotedrug can be given to antagonizeAntidotedrug can be given to antagonize

the toxic effects of another drugthe toxic effects of another drug


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AgeAge

PregnancyPregnancy

Body weightBody weight Gender-hormonal effectsGender-hormonal effects

Pathologic conditionsPathologic conditions

Placebo responsePlacebo response


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Genetics-hepatic drug metabolizingGenetics-hepatic drug metabolizing

enzymes===acetyltransferase. Rapid acetylatorsenzymes===acetyltransferase. Rapid acetylators

may need larger than usual dosages andmay need larger than usual dosages and

conversely, smaller doses if slow acetylatorsconversely, smaller doses if slow acetylators Glucose-6-phosphate deficiencydevelopGlucose-6-phosphate deficiencydevelop

hemolytic anemia if take antimalarials orhemolytic anemia if take antimalarials or

sulfonamidessulfonamides

EthnicityACE inhibitors in African AmericansEthnicityACE inhibitors in African Americans

Tolerance and cross toleranceTolerance and cross tolerance


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Adverse effects of drugsAdverse effects of drugs

CNSCNS

GIGI

Hematologic-anticonvulsantsHematologic-anticonvulsants

Hepatic-acetaminophen, INHHepatic-acetaminophen, INH

Nephrotoxicity-aminoglycosides, NSAIDSNephrotoxicity-aminoglycosides, NSAIDS

HypersensitivityHypersensitivity

Drug fever-fever associated w/administration ofDrug fever-fever associated w/administration of

some antimicrobials, atropine or TCAssome antimicrobials, atropine or TCAs


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Adverse Drug EffectsAdverse Drug Effects

Drug dependencyDrug dependency

IdiosyncrasyIdiosyncrasy

CarcinogenicityCarcinogenicity teratogenicityteratogenicity


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ToxicologyDrug OverdosageToxicologyDrug Overdosage

General managementGeneral management

1.1. CPRCPR

2.2. ETTETT

3.3. IVIV4.4. Check blood sugar, drug screen, liver and kidneyCheck blood sugar, drug screen, liver and kidney

functionfunction

5.5. CharcoalCharcoal

6.6. Narcan or possibly antidotesNarcan or possibly antidotes7.7. May alkalinize the urine to prevent kidneyMay alkalinize the urine to prevent kidney

damagedamage


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Antidotes for Selected TherapeuticAntidotes for Selected Therapeutic

DrugsDrugs

Acetaminophen-mucomystAcetaminophen-mucomyst

Digoxin-digibindDigoxin-digibind

Beta blockers-Glucagon (increasesBeta blockers-Glucagon (increasesmyocardial contractility)myocardial contractility)

Phenothiazines-benadryl (EPS)Phenothiazines-benadryl (EPS)

Coumadin-vitamin KCoumadin-vitamin K

Heparin-protamine sulfateHeparin-protamine sulfate


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Antidotes cont.Antidotes cont.

BenzodiazepinesflumazenilBenzodiazepinesflumazenil

Cholinergics-atropineCholinergics-atropine

Calcium channel blockerscalciumCalcium channel blockerscalciumgluconategluconate


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General Principles of accurate drugGeneral Principles of accurate drug

administrationadministration

Six RightsSix Rights

1.1. Right patientRight patient

2.2. Right drugRight drug3.3. Right doseRight dose

4.4. Right routeRight route

5.5. Right timeRight time

6.6. Right documentationRight documentation


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General Principles cont.General Principles cont.

Follow the rights consistentlyFollow the rights consistently

Learn essential information about each drugLearn essential information about each drug

Interpret prescribers orders correctlyInterpret prescribers orders correctly Read labels for right medication andRead labels for right medication and

concentrationconcentration


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Drug AdministrationDrug Administration

Minimize the use of abbreviationsMinimize the use of abbreviations

Calculate dosages correctlyCalculate dosages correctly

Measure doses accuratelyMeasure doses accurately Use appropriate anatomic landmarks toUse appropriate anatomic landmarks to

identify sites of IM injections-followidentify sites of IM injections-follow

manufacturers recommendationsmanufacturers recommendations Verify client identityVerify client identity


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Legal ResponsibilitiesLegal Responsibilities

Nurse is legally responsible for safe and accurateNurse is legally responsible for safe and accurateadministration of medicationsadministration of medications

Nurse is expected to have sufficient drugNurse is expected to have sufficient drugknowledge to recognize and question erroneousknowledge to recognize and question erroneousordersorders

Unit dose wrappings of oral drugs should be left inUnit dose wrappings of oral drugs should be left inplace until the nurse is in the presence of the clientplace until the nurse is in the presence of the clientand ready to administer the medicationand ready to administer the medication


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Medication OrdersMedication Orders

Include the full name of the patientInclude the full name of the patient

Generic or trade name of the drugGeneric or trade name of the drug

The dose, the route and frequency ofThe dose, the route and frequency ofadministrationadministration

Date, time and signature of the prescriberDate, time and signature of the prescriber


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Common abbreviationsCommon abbreviations

POPO

IMIM

IVIV SLSL

Sub qSub q


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Drug DosagesDrug Dosages

cccc

gg

GrGr

gttgtt

mLmL

ozoz

TspTsp

tbsptbsp


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Routes of AdministrationRoutes of Administration

OralOral

Via GI tubeVia GI tube

Parenteral-IM, IV and sub qParenteral-IM, IV and sub q TopicalTopical

Rectal, ophthalmicRectal, ophthalmic

OticOtic vaginalvaginal


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Sites for injectionsSites for injections

Sub q-abdomen, thighs, back and upperSub q-abdomen, thighs, back and upper

armsarms

IM-deltoid, dorsogluteal, ventrogluteal andIM-deltoid, dorsogluteal, ventrogluteal and

vastus lateralis musclesvastus lateralis muscles

IV-antecubital, hands, arms, external jugularIV-antecubital, hands, arms, external jugular

Others: intradermal, intra-articular, intra-Others: intradermal, intra-articular, intra-arterial and intrathecalarterial and intrathecal


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EquivalentsEquivalents

MetricMetric

ApothecaryApothecary

HouseholdHousehold (see p. 37)(see p. 37)


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Drug administration cardinal rulesDrug administration cardinal rules

Wash hands before giving medsWash hands before giving meds

Read MAR carefully. If ever in doubt, checkRead MAR carefully. If ever in doubt, check

the original orderthe original order

NeverNevergive medications you are uncertain ofgive medications you are uncertain of

unless you have looked them up or haveunless you have looked them up or have

consulted with pharmacyconsulted with pharmacy


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Drug Administration Cardinal RulesDrug Administration Cardinal Rules

NeverNevergive more than 3cc per IM injectiongive more than 3cc per IM injection

Wear gloves with all injectionsWear gloves with all injections

For sub q injections, use 25G, 5/8 needlesFor sub q injections, use 25G, 5/8 needles Do not give oral meds if patient is vomiting,Do not give oral meds if patient is vomiting,

sedated, NPO or is unconscioussedated, NPO or is unconscious

Follow narcotic protocol for signing out ofFollow narcotic protocol for signing out ofnarcoticsnarcotics


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Nursing Process in Drug TherapyNursing Process in Drug Therapy

Is a systematic way of gathering and usingIs a systematic way of gathering and using

information to plan and provideinformation to plan and provide

individualized client care and to evaluate theindividualized client care and to evaluate the

outcomes of careoutcomes of care

Five steps of the nursing process are:Five steps of the nursing process are:

assessment, nursing diagnosis, planning,assessment, nursing diagnosis, planning,

interventions and evaluationinterventions and evaluation


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General Principles of Drug TherapyGeneral Principles of Drug Therapy

Expected benefits should outweigh potentialExpected benefits should outweigh potential

adverse effectsadverse effects

Drug therapy should be individualizedDrug therapy should be individualized

Drug effects on quality of life should beDrug effects on quality of life should be

considered in designing a drug therapyconsidered in designing a drug therapy

regimentregiment


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Drug selection and dosageDrug selection and dosage

Use as few drugs as possibleUse as few drugs as possible

Fixed dose combinations increaseFixed dose combinations increasecompliancecompliance

Lowest dose with therapeutic effectLowest dose with therapeutic effect

Follow guidelines but dosages must beFollow guidelines but dosages must beindividualizedindividualized

Drugs with long half-lives may requireDrugs with long half-lives may requireloading doses then titrated lowerloading doses then titrated lowermaintenance dosesmaintenance doses

D Th i i l l tiD Th i i l l ti


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Drug Therapy in special populations-Drug Therapy in special populations-

pediatricspediatrics

Pediatrics-all aspects must be guided by thePediatrics-all aspects must be guided by the

childs age, weight and level of growth andchilds age, weight and level of growth and

developmentdevelopment

Safe therapeutic ranges are less well-Safe therapeutic ranges are less well-

defineddefined

Choice of drug is restricted because manyChoice of drug is restricted because many

drugs used in adults have not beendrugs used in adults have not been

sufficiently investigatedsufficiently investigated

P di t i h i l i h t i tiP di t i h i l i h t i ti


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Pediatric physiologic characteristicsPediatric physiologic characteristics

affecting pharmacokineticsaffecting pharmacokinetics

Thin, permeable skin increased absorptionThin, permeable skin increased absorption

of topicalsof topicals

Immature blood-brain barrierincreasedImmature blood-brain barrierincreased

distribution into the CNS until age 2distribution into the CNS until age 2

Altered protein binding until age 1Altered protein binding until age 1

Decreased activity of metabolizing enzymesDecreased activity of metabolizing enzymesin infants, increased in childrenin infants, increased in children


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Pediatric physiologic effectsPediatric physiologic effects

Increased percentage of body waterIncreased percentage of body water

Decreased GFR until one year of ageDecreased GFR until one year of age


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PediatricsPediatrics

Oral route for meds is preferableOral route for meds is preferable

For injections, may wish to use EMLAFor injections, may wish to use EMLA

(eutectic mixture of lidocaine and prilocaine,(eutectic mixture of lidocaine and prilocaine,

local anesthetics)local anesthetics)

Site selection for injectionsinfants, useSite selection for injectionsinfants, use

thigh muscles; older than 18 months of age,thigh muscles; older than 18 months of age,

use deltoid; older than 3, use ventroglutealuse deltoid; older than 3, use ventrogluteal

musclemuscle

Drug Therapy in Older AdultsDrug Therapy in Older Adults


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Drug Therapy in Older Adultsg py

Physiologic characteristics andPhysiologic characteristics and

pharmacokinetic impactpharmacokinetic impact Decreased GI motilityslower absorptionDecreased GI motilityslower absorption

Decreased cardiac outputslowerDecreased cardiac outputslower

absorption from site of administration,absorption from site of administration,decreased distribution to sites of action indecreased distribution to sites of action in

tissuestissues

Decreased blood flow to liver and kidneys-Decreased blood flow to liver and kidneys-delayed metabolism and excretiondelayed metabolism and excretion


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Decreased total body water and lean bodyDecreased total body water and lean body

mass-fat soluble meds stay with patientmass-fat soluble meds stay with patient

longer, water soluble drugs are distributed inlonger, water soluble drugs are distributed in

smaller area, greater risk for toxicitysmaller area, greater risk for toxicity

Decreased blood flow to liver-slowedDecreased blood flow to liver-slowed

metabolism and detox of drugsmetabolism and detox of drugs


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Decreased albumin-decreased availability ofDecreased albumin-decreased availability of

protein for binding and transporting. Willprotein for binding and transporting. Will

also have higher concentration of free activealso have higher concentration of free active

drug.drug.

Decreased blood flow to kidneysimpairedDecreased blood flow to kidneysimpaired

drug excretion, potential toxicitydrug excretion, potential toxicity

Old Ad ltOlder Ad lts


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Older AdultsOlder Adults

Renal ImpairmentRenal Impairment

Know baseline renal functionKnow baseline renal function

Tailor dosagesTailor dosages

Avoid nephrotoxic medicationsAvoid nephrotoxic medications Be aware of need for additional dosing ifBe aware of need for additional dosing if

patient is receiving renal replacementpatient is receiving renal replacement

therapytherapy

Old Ad ltOlder Adults


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Hepatic ImpairmentHepatic Impairment

Those with cirrhosis, hepatitis, receivingThose with cirrhosis, hepatitis, receiving

hepatotoxic drugs, have heart failure, arehepatotoxic drugs, have heart failure, are

undergoing major surgery or have had trauma areundergoing major surgery or have had trauma are

at higher risk for toxicities r/t medicationsat higher risk for toxicities r/t medications Know drug effects on hepatic functionKnow drug effects on hepatic function

Reduce dosages on medications that areReduce dosages on medications that are

extensively metabolized by the liver such as:extensively metabolized by the liver such as:

cimetidine, phenytoin, ranitidine, theophyllinecimetidine, phenytoin, ranitidine, theophylline

Old Ad ltOlder Adults


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Critical IllnessesCritical Illnesses

Be aware that all medications may haveBe aware that all medications may have

variable effects in this scenariovariable effects in this scenario

Know the actions, usual dosages and sideKnow the actions, usual dosages and side

effects of medicationseffects of medications

Closely monitor renal and liver function testsClosely monitor renal and liver function tests

Monitor serum protein and albumin levelsMonitor serum protein and albumin levels

Older Ad ltsOlder Adults


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Critical IllnessCritical Illness

Most drugs will be given IV-for this reason,Most drugs will be given IV-for this reason,

medications may have faster onsetmedications may have faster onset

Many factors may interfere with drug effectsMany factors may interfere with drug effects

if given orallyif given orally

Considerations when giving medications viaConsiderations when giving medications via

feeding tubefeeding tube

Appropriate scheduling very importantAppropriate scheduling very important


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Drug Therapy in Home CareDrug Therapy in Home Care

On patients turfOn patients turf

Schedule visit at convenient time for patientSchedule visit at convenient time for patient

and caregiverand caregiver

Assess patients ability to perform self-careAssess patients ability to perform self-care

Assess patients understanding and attitudeAssess patients understanding and attitude

regarding medication regimenregarding medication regimen Inquire if patient is taking any herbalInquire if patient is taking any herbal

preparationspreparations


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Drug Therapy in Home CareDrug Therapy in Home Care

Inquire if patient is taking any OTC medsInquire if patient is taking any OTC meds

Assess environment for safetyAssess environment for safety

Educate patient and caregiver indication,Educate patient and caregiver indication,proper administration and side effects ofproper administration and side effects of

administered medicationsadministered medications

Between visits, maintain contact with patientBetween visits, maintain contact with patientto monitor progress and serve as a resourceto monitor progress and serve as a resource


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Herbal and Dietary SupplementsHerbal and Dietary Supplements

Black cohosh-used to relieve menopausalBlack cohosh-used to relieve menopausal

s/ss/s

Capsaicin-post-herpetic neuralgiaCapsaicin-post-herpetic neuralgia

Echinacea-anti-infective, for common coldEchinacea-anti-infective, for common cold

Gingernausea. Not for morning sickness.Gingernausea. Not for morning sickness.

Garlic-cholesterol loweringGarlic-cholesterol lowering


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Herbal and Dietary supplementsHerbal and Dietary supplements

Feverfew-for migraines, menstrualFeverfew-for migraines, menstrual

complaints. Can cause withdrawal s/s.complaints. Can cause withdrawal s/s.

Ginseng-increase stamina, endurance andGinseng-increase stamina, endurance and

mental acuity. Can affect bleeding time, BP,mental acuity. Can affect bleeding time, BP,

increase hypoglycemia. No longer than 3increase hypoglycemia. No longer than 3

weeks use with Siberian ginseng.weeks use with Siberian ginseng.


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Introduction to Drug Therapy