presentation1 a pharmacology

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PharmacologyPharmacology

Rosalie C. Villora, MSN, RNRosalie C. Villora, MSN, RN

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ObjectivesObjectives Identify principles of pharmacology that relate to nursing Identify principles of pharmacology that relate to nursing

care.care. Describe the 5 steps of the nursing process.Describe the 5 steps of the nursing process. Explain how nursing process is used in the administration of Explain how nursing process is used in the administration of

medicationsmedications Explain absorption, excretion, desired effect.Explain absorption, excretion, desired effect. Identify elements in a patient drug historyIdentify elements in a patient drug history Identify common elements in a variety of hospital Identify common elements in a variety of hospital

medication recordsmedication records Discuss charting dos and don’tsDiscuss charting dos and don’ts Discuss confidentiality issues as they apply to medication Discuss confidentiality issues as they apply to medication

administrationadministration

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TerminologyTerminology Drug - any chemical that affects the physiologic processes of

a living organism

Pharmacology - the study or science of drugs

Chemical name - describes the drug’s chemical composition and molecular structure

Generic name (nonproprietary name) - name given by the United States Adopted Name Council

Trade name (proprietary name) - each drug has a registered trademark; use of the name restricted by the drug’s patent owner (usually the manufacturer)

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Pharmacologic PrinciplesPharmacologic Principles Pharmaceutics - the study of how various drug forms the study of how various drug forms

influence pharmacokinetic and pharmacodynamic activitiesinfluence pharmacokinetic and pharmacodynamic activities

Pharmacokinetics - the study of what the body does to the - the study of what the body does to the drugdrug AbsorptionAbsorption DistributionDistribution MetabolismMetabolism ExcretionExcretion

Pharmacodynamics - the study of what the drug does to the - the study of what the drug does to the body, i.e. the mechanism of drug actions in living tissuesbody, i.e. the mechanism of drug actions in living tissues

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Pharmacologic Principles cont’dPharmacologic Principles cont’d Pharmacotherapeutics - The use of drugs and the clinical - The use of drugs and the clinical

indications for drugs to prevent and treat diseasesindications for drugs to prevent and treat diseases Empirical therapeutics – effective, but mechanism of action Empirical therapeutics – effective, but mechanism of action

is unknownis unknown Rational therapeutics – specific evidence has been obtained Rational therapeutics – specific evidence has been obtained

for the mechanisms of drug actionfor the mechanisms of drug action

Pharmacognosy - The study of natural (plant and animal) - The study of natural (plant and animal) drug sourcesdrug sources

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PharmaceuticsPharmaceutics

Dosage form design affects dissolutionDosage form design affects dissolution

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Pharmacokinetics: AbsorptionPharmacokinetics: Absorption The rate at which a drug leaves

its site of administration, & the extent to which absorption occurs Bioavailability – a measure

of the extent of drug absorption in the body (0% to 100%)

Bioequivalent – two drugs have the same bioavailability and same concentration of active ingredients

Factors That Affect Absorption

Food or fluids administered Food or fluids administered with the drugwith the drug

Dosage formulationDosage formulation Status of the absorptive Status of the absorptive

surfacesurface Rate of blood flow to the Rate of blood flow to the

small intestinesmall intestine Acidity of the stomachAcidity of the stomach Status of GI motilityStatus of GI motility

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RoutesRoutes

Enteral (GI tract) Oral Sublingual Buccal – oral mucosa

between the cheek and gum

Parenteral Topical

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First-Pass EffectFirst-Pass Effect

The metabolism of a drug and its passage The metabolism of a drug and its passage from the liver into the circulationfrom the liver into the circulation

– – A drug given via the oral route may be extensively A drug given via the oral route may be extensively metabolized by the liver before reaching the systemic metabolized by the liver before reaching the systemic circulation (high first-pass effect)circulation (high first-pass effect)

– – The same drug—given IV—bypasses the liver, The same drug—given IV—bypasses the liver, preventing the first-pass effect from taking place, and preventing the first-pass effect from taking place, and more drug reaches the circulationmore drug reaches the circulation

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Drugs to be taken on empty Drugs to be taken on empty stomachstomach alendronate sodiumalendronate sodium risedronate sodiumrisedronate sodium

Drugs to be taken with foodDrugs to be taken with food CarbamazepineCarbamazepine IronIron HydralazineHydralazine LithiumLithium PropanololPropanolol SpironolactoneSpironolactone TheophyllineTheophylline

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Parenteral RouteParenteral Route

Intravenous (fastest Intravenous (fastest delivery into the blood delivery into the blood circulation)circulation)

IntramuscularIntramuscular SubcutaneousSubcutaneous IntradermalIntradermal IntrathecalIntrathecal IntraarticularIntraarticular

Topical RouteTopical Route

Skin - transdermal Skin - transdermal patchespatches

EyesEyes EarsEars NoseNose Lungs (inhalation)Lungs (inhalation) RectumRectum VaginaVagina

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Distribution

Protein-bindingProtein-binding

Water soluble vs. fat solubleWater soluble vs. fat soluble

Blood-brain barrierBlood-brain barrier

Areas of rapid distribution: Areas of rapid distribution: heart, liver, kidneys, brainheart, liver, kidneys, brain

Areas of slow distribution: Areas of slow distribution: muscle, skin, fatmuscle, skin, fat

Metabolism (Biotransformation)

Liver (main organ)Liver (main organ) Skeletal muscleSkeletal muscle KidneysKidneys LungsLungs PlasmaPlasma Intestinal mucosaIntestinal mucosa

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Factors that metabolism

Fast acetylator Barbiturate therapy Rifampin therapy

Factors that metabolism

Cardiovascular Cardiovascular dysfunctiondysfunction

Renal insufficiencyRenal insufficiency StarvationStarvation Obstructive jaundiceObstructive jaundice Slow acetylatorSlow acetylator Erythromycin or Erythromycin or

ketoconazole drug therapyketoconazole drug therapy

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Delayed drug metabolism results in:

Accumulation of drugsAccumulation of drugs

Prolonged action of the Prolonged action of the drugsdrugs

Stimulating drug metabolism causes:

Diminished pharmacologic Diminished pharmacologic effectseffects

Cytochrome P-450 enzymes Cytochrome P-450 enzymes

Also known as microsomal Also known as microsomal enzymesenzymes

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ExcretionExcretion

The elimination of drugs from the bodyThe elimination of drugs from the body Kidneys (main organ)Kidneys (main organ) LiverLiver BowelBowel

Biliary excretionBiliary excretion Enterohepatic recirculationEnterohepatic recirculation

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Half-lifeHalf-life

The time it takes for one half of the original The time it takes for one half of the original amount of a drug in the body to be removedamount of a drug in the body to be removed

A measure of the rate at which drugs are A measure of the rate at which drugs are removed from the bodyremoved from the body

Most drugs are considered to be effectively Most drugs are considered to be effectively removed after about five half-livesremoved after about five half-lives

Steady stateSteady state

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The Movement of DrugsThe Movement of DrugsThrough the BodyThrough the Body

Drug actionsDrug actions The cellular processes involved in the drug The cellular processes involved in the drug

and cell interactionand cell interaction

Drug effectDrug effect The physiologic reaction of the body to the The physiologic reaction of the body to the

drugdrug

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Onset, Peak, and DurationOnset, Peak, and DurationOnset The time it takes for the drug to elicit a therapeutic response

Peak The time it takes for a drug to reach its maximum therapeutic

response Highest blood level

Trough Level Lowest blood level

Duration The time a drug concentration is sufficient to elicit a

therapeutic response

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Pharmacodynamics: Pharmacodynamics: Mechanisms of ActionMechanisms of Action

Receptor interactionsReceptor interactions Enzyme interactionsEnzyme interactions Nonspecific interactionsNonspecific interactions

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Pharmacotherapeutics: Pharmacotherapeutics: Types of TherapiesTypes of Therapies

Acute therapyAcute therapy Maintenance therapyMaintenance therapy Supplemental/replacement therapySupplemental/replacement therapy Palliative therapyPalliative therapy Supportive therapySupportive therapy Prophylactic therapyProphylactic therapy Empiric therapyEmpiric therapy

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ContraindicationContraindication- a- any characteristic of the patient, ny characteristic of the patient, especially a disease state, that makes the use of a given especially a disease state, that makes the use of a given medication dangerous for the patientmedication dangerous for the patient

Intended therapeutic actionIntended therapeutic action (beneficial) (beneficial)

Unintended but potential adverse effects (predictable, adverse Unintended but potential adverse effects (predictable, adverse reactions)reactions)

Therapeutic indexTherapeutic index - t - the ratio between a drug’s therapeutic he ratio between a drug’s therapeutic benefits and its toxic effectsbenefits and its toxic effects

ToleranceTolerance - - a decreasing response to repeated drug dosesa decreasing response to repeated drug doses

DependenceDependence - a physiologic or psychological need for a drug - a physiologic or psychological need for a drug

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Drug interactions: the alteration of action of a drug by other prescribed drugs, over-the-counter medications, & herbal therapies

Drug interactionsDrug interactions Additive effectAdditive effect Synergistic effectSynergistic effect Antagonistic effectAntagonistic effect IncompatibilityIncompatibility

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Adverse Drug EventsAdverse Drug Events

Medication errorsMedication errors Adverse drug reactions:Adverse drug reactions:

Pharmacologic Pharmacologic reactions, including reactions, including adverse effectsadverse effects

Hypersensitivity Hypersensitivity (allergic) reaction(allergic) reaction

Idiosyncratic reactionIdiosyncratic reaction Drug interactionDrug interaction

Adverse effectsAdverse effects Predictable, well-known Predictable, well-known

reactions that result in reactions that result in little or no change in little or no change in patient managementpatient management

Predictable frequencyPredictable frequency Occurrences are related Occurrences are related

to the size of the doseto the size of the dose Usually resolve when Usually resolve when

the drug is discontinuedthe drug is discontinued

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Other Drug-Related EffectsOther Drug-Related Effects

Teratogenic – results in structural defects in the fetusTeratogenic – results in structural defects in the fetus

Mutagenic – permanent changes in the genetic Mutagenic – permanent changes in the genetic composition and chromosome structure of living composition and chromosome structure of living organismorganism

Carcinogenic – cancer-causing effects of drugsCarcinogenic – cancer-causing effects of drugs

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Pharmacognosy

Four main sources for drugs

PlantsPlants AnimalsAnimals MineralsMinerals Laboratory synthesisLaboratory synthesis

Toxicology

The study of poisons The study of poisons and unwanted and unwanted responses to drugs responses to drugs and other chemicalsand other chemicals

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Life Span ConsiderationLife Span Consideration

PregnancyPregnancy Breast-feedingBreast-feeding Neonatal and PediatricNeonatal and Pediatric ElderlyElderly

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Neonatal and Pediatric Considerations: Pharmacokinetics

Absorption Gastric pH less Gastric pH less

acidicacidic Gastric emptying is Gastric emptying is

slowedslowed Intramuscular Intramuscular

absorption faster and absorption faster and irregularirregular

Distribution The younger the person,

the greater the % of total body water

Greater TBW means fat content is lower

Decreased level of protein binding

Immature blood-brain barrier—more drugs enter the brain

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Neonatal and Pediatric Considerations: Pharmacokinetics

Metabolism

Liver immature, does not produce enough microsomal enzymes

Older children may have increased metabolism, requiring higher doses than infants

Excretion

Kidney immaturity affects glomerular filtration rate and tubular secretion

Decreased perfusion rate of the kidneys may reduce excretion of drugs

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The ElderlyThe Elderly

Elderly: older than age 65 Healthy People 2010:

older than age 55 Use of OTC medications Increased incidence of

chronic illnesses Polypharmacy - “prescribing

cascade”

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The Elderly: The Elderly: PharmacokineticsPharmacokinetics

Absorption Gastric pH less acidic Slowed gastric emptying Movement through GI

tract slower Reduced blood flow to

the GI tract Reduced absorptive

surface area due to flattened intestinal villi

Distribution TBW percentages lower Fat content increased Decreased production of

proteins by the liver, resulting in decreased protein binding of drugs (and increased circulation of free drugs)

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The Elderly: The Elderly: PharmacokineticsPharmacokinetics

MetabolismMetabolism Aging liver produces Aging liver produces

fewer microsomal fewer microsomal enzymes, affecting enzymes, affecting drug metabolismdrug metabolism

Reduced blood flow Reduced blood flow to the liverto the liver

ExcretionExcretion Decreased Decreased

glomerular filtration glomerular filtration raterate

Decreased number Decreased number of intact nephronsof intact nephrons

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Pharmacology Pharmacology &&

The Nursing ProcessThe Nursing Process

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The Nursing ProcessThe Nursing Process

A research-based organizational framework A research-based organizational framework for professional nursing practicefor professional nursing practice

Central to all nursing careCentral to all nursing care Encompasses all steps taken by the nurse in Encompasses all steps taken by the nurse in

caring for a patientcaring for a patient Flexibility is importantFlexibility is important Critical thinkingCritical thinking Ongoing and constantly evolving processOngoing and constantly evolving process

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The Nursing Process (cont’d)The Nursing Process (cont’d)

AssessmentAssessment Nursing diagnosisNursing diagnosis Planning Planning GoalsGoals Outcome criteriaOutcome criteria ImplementationImplementation EvaluationEvaluation

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AssessmentAssessment Data collection Data collection

Subjective, objectiveSubjective, objective Medication historyMedication history

PrescriptionsPrescriptions OTCsOTCs HerbalsHerbals Responses to medications (therapeutic and adverse Responses to medications (therapeutic and adverse

responses)responses)

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Nursing diagnosisNursing diagnosis Decision about the need/problem (actual or at Decision about the need/problem (actual or at

risk for) of the patientrisk for) of the patient Critical thinking, creativity, and accurate data Critical thinking, creativity, and accurate data

collectioncollection NANDA formatNANDA format

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Nursing diagnosisNursing diagnosis

Three stepsThree steps Human response to Human response to

illness (actual or illness (actual or risk)risk)

““related to”related to” ““as evidenced by”as evidenced by”

PlanningPlanning Identification of Identification of

goals and outcome goals and outcome criteriacriteria

Time frameTime frame PrioritizationPrioritization

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GoalsGoals

S- specificS- specific M- measurableM- measurable A- attainableA- attainable R- realisticR- realistic T- time frame T- time frame

specifiedspecified

Outcome CriteriaOutcome Criteria

Specific standard (s) Specific standard (s) of measureof measure

Patient orientedPatient oriented

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ImplementationImplementation Initiation and completion of the Initiation and completion of the

nursing care plan as defined by the nursing care plan as defined by the nursing diagnoses and outcome criterianursing diagnoses and outcome criteria

Follow the “Six Rights” of medication Follow the “Six Rights” of medication administrationadministration

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The Six Rights of The Six Rights of Medication AdministrationMedication Administration

Right drugRight drug Right doseRight dose Right timeRight time Right routeRight route Right patientRight patient Right documentationRight documentation

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Another “Right”—Constant System Another “Right”—Constant System AnalysisAnalysis

A “double-check”A “double-check” The entire “system” of medication The entire “system” of medication

administrationadministration Ordering, dispensing, preparing, Ordering, dispensing, preparing,

administering, documentingadministering, documenting Involves the physician, nurse, nursing unit, Involves the physician, nurse, nursing unit,

pharmacy department, and patient educationpharmacy department, and patient education

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Other “Rights” (cont’d)Other “Rights” (cont’d)

Close consideration of special situationsClose consideration of special situations Prevention and reporting of medication errorsPrevention and reporting of medication errors Patient teachingPatient teaching Monitor therapeutic effects, adverse effects, Monitor therapeutic effects, adverse effects,

and toxic effectsand toxic effects Refusal of medicationRefusal of medication

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Six Elements of a Drug OrderSix Elements of a Drug Order

1. Patient's name1. Patient's name2. Date order is written2. Date order is written3. Name of medication3. Name of medication4. Dosage (includes size, 4. Dosage (includes size,

frequency, and number of frequency, and number of doses)doses)

5. Route of delivery5. Route of delivery6. Signature of the prescriber6. Signature of the prescriber

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EvaluationEvaluation

Ongoing part of the nursing Ongoing part of the nursing processprocess

Determining the status of the Determining the status of the goals and goals and outcomes of careoutcomes of care

Monitoring the patient’s Monitoring the patient’s response to drug therapyresponse to drug therapy Expected and unexpected Expected and unexpected

responsesresponses

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