Download - Pharmacology in Nursing
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Positive Inotropic AgentsPositive Inotropic Agents
Pharmacology in NursingPharmacology in Nursing
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DefinitionDefinition
Drugs that increase the force of myocardial Drugs that increase the force of myocardial contractioncontraction
Used to treat heart muscle failureUsed to treat heart muscle failure Cardiac glycosidesCardiac glycosides
digoxindigoxin Phosphodiesterase inhibitors ( PDIs)Phosphodiesterase inhibitors ( PDIs)
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Heart FailureHeart Failure
The heart is unable to pump blood in The heart is unable to pump blood in sufficient amounts from the ventricles to meet sufficient amounts from the ventricles to meet the body’s metabolic needsthe body’s metabolic needs
Impairs heart’s ability to fill or eject properlyImpairs heart’s ability to fill or eject properly Symptoms depend on cardiac area affectedSymptoms depend on cardiac area affected
Left ventricular failureLeft ventricular failure Right ventricular failureRight ventricular failure
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What happens when the heart What happens when the heart fails?fails?
Weakened heart is unable to pump blood in Weakened heart is unable to pump blood in sufficient amountssufficient amounts
Decrease in CO, decrease tissue perfusionDecrease in CO, decrease tissue perfusion Compensatory mechanisms help to maintain Compensatory mechanisms help to maintain
CO and arterial blood pressureCO and arterial blood pressure Renin-angiotensin-aldosterone system Renin-angiotensin-aldosterone system
activated as a compensatory mechanismactivated as a compensatory mechanism As cardiac output decreases, SNS releases As cardiac output decreases, SNS releases
catecholamines which increase HR, catecholamines which increase HR, contractility & vasoconstrictioncontractility & vasoconstriction
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What happens when the heart What happens when the heart fails?fails?
As renal perfusion decreases, renin is As renal perfusion decreases, renin is released by kidneyreleased by kidney
Vasoconstriction increases SVR, which Vasoconstriction increases SVR, which increases afterloadincreases afterload
End result, the failing heart must now work End result, the failing heart must now work HARDER to pump bloodHARDER to pump blood
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Heart Failure: CausesHeart Failure: Causes Cardiac defectCardiac defect
Myocardial infarctionMyocardial infarction Valve deficiencyValve deficiency
Defect outside the heartDefect outside the heart Coronary artery disease/HypertensionCoronary artery disease/Hypertension Pulmonary hypertensionPulmonary hypertension DiabetesDiabetes
Supraventricular dysrhythmiasSupraventricular dysrhythmias Atrial fibrillationAtrial fibrillation Atrial flutterAtrial flutter
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Treatment of Heart FailureTreatment of Heart Failure
Block the compensatory mechanismsBlock the compensatory mechanisms Treat underlying conditionsTreat underlying conditions Goal is to decrease SVR, decrease volume,Goal is to decrease SVR, decrease volume, Increase cardiac outputIncrease cardiac output
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Cardiac GlycosidesCardiac Glycosides
Originally obtained from Originally obtained from DigitalisDigitalis plant, plant, foxglovefoxglove
Digoxin is the prototypeDigoxin is the prototype Used in heart failure and to control ventricular Used in heart failure and to control ventricular
response to atrial fibrillation or flutterresponse to atrial fibrillation or flutter
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Cardiac Glycosides:Cardiac Glycosides:Mechanism of ActionMechanism of Action
Increase myocardial contractilityIncrease myocardial contractility Change electrical conduction properties of the heartChange electrical conduction properties of the heart
Decrease rate of electrical conductionDecrease rate of electrical conduction Prolong the refractory periodProlong the refractory period
• Area between SA node and AV nodeArea between SA node and AV node
Result: reduced heart rate and improved cardiac Result: reduced heart rate and improved cardiac
efficiencyefficiency
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Drug Effects:Drug Effects:General TermsGeneral Terms
InotropicInotropic Force or energy of muscular contractionsForce or energy of muscular contractions
ChronotropicChronotropic Rate of the heartbeatRate of the heartbeat
DromotropicDromotropic The conduction of electrical impulsesThe conduction of electrical impulses
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How Positive Inotropic Agents How Positive Inotropic Agents WorkWork
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Cardiac Glycosides:Cardiac Glycosides:Drug EffectsDrug Effects
Positive inotropic effectPositive inotropic effect Increase in force and velocity of myocardial contraction Increase in force and velocity of myocardial contraction
(without an increase in oxygen consumption)(without an increase in oxygen consumption) Negative chronotropic effectNegative chronotropic effect
Reduced heart rateReduced heart rate Negative dromotropic effectNegative dromotropic effect
Decreases automaticity at SA node, decreases AV nodal Decreases automaticity at SA node, decreases AV nodal conduction, and other effectsconduction, and other effects
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Cardiac Glycosides:Cardiac Glycosides:Drug Effects (cont’d)Drug Effects (cont’d)
Increased stroke volumeIncreased stroke volume Reduction in heart size during diastoleReduction in heart size during diastole Decrease in venous BP and vein engorgementDecrease in venous BP and vein engorgement Increase in coronary circulationIncrease in coronary circulation Promotion of diuresis due to improved blood Promotion of diuresis due to improved blood
circulationcirculation Palliation of exertional and paroxysmal nocturnal Palliation of exertional and paroxysmal nocturnal
dyspnea, cough, and cyanosisdyspnea, cough, and cyanosis
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Cardiac Glycosides:Cardiac Glycosides:IndicationsIndications
Heart failureHeart failure Supraventricular dysrhythmiasSupraventricular dysrhythmias
Atrial fibrillation and atrial flutterAtrial fibrillation and atrial flutter
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Heart FailureHeart Failure
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Atrial Fibrillation/FlutterAtrial Fibrillation/Flutter
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Cardiac Glycosides:Cardiac Glycosides:Adverse EffectsAdverse Effects
Digoxin (Lanoxin)Digoxin (Lanoxin) Very narrow therapeutic windowVery narrow therapeutic window Drug levels must be monitoredDrug levels must be monitored Low potassium levels increase its toxicityLow potassium levels increase its toxicity Electrolyte levels must be monitoredElectrolyte levels must be monitored
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Digoxin: Digoxin: Adverse EffectsAdverse Effects
CardiovascularCardiovascular Dysrhythmias, including bradycardia or Dysrhythmias, including bradycardia or
tachycardiatachycardia CNSCNS
Headaches, fatigue, malaise, confusion, Headaches, fatigue, malaise, confusion, convulsionsconvulsions
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Digoxin: Digoxin: Adverse Effects (cont’d)Adverse Effects (cont’d)
EyeEye Colored vision (seeing green, yellow, purple), halo Colored vision (seeing green, yellow, purple), halo
vision, flickering lightsvision, flickering lights GIGI
Anorexia, nausea, vomiting, diarrheaAnorexia, nausea, vomiting, diarrhea
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Digoxin ToxicityDigoxin Toxicity
digoxin immune Fab (Digibind) therapydigoxin immune Fab (Digibind) therapy Hyperkalemia (serum potassium greater than Hyperkalemia (serum potassium greater than
5 mEq/L) in a digitalis-toxic patient5 mEq/L) in a digitalis-toxic patient Life-threatening cardiac dysrhythmiasLife-threatening cardiac dysrhythmias Life-threatening digoxin overdoseLife-threatening digoxin overdose Therapeutic drug level= 0.5 – 2 ng/mlTherapeutic drug level= 0.5 – 2 ng/ml
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Conditions That Are Predisposing Conditions That Are Predisposing to Digoxin Toxicityto Digoxin Toxicity
HypokalemiaHypokalemia Use of cardiac pacemakerUse of cardiac pacemaker Hepatic dysfunctionHepatic dysfunction HypercalcemiaHypercalcemia DysrhythmiasDysrhythmias Hypothyroid, respiratory, or renal diseaseHypothyroid, respiratory, or renal disease Advanced ageAdvanced age
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Dosing DigoxinDosing Digoxin
Adult Digitalizing Dose:Adult Digitalizing Dose:
PO or IV : 1-1.5 mg/day (4 doses)PO or IV : 1-1.5 mg/day (4 doses)
Usual maintenance dose 0.125 mg- 0.5 mg dayUsual maintenance dose 0.125 mg- 0.5 mg day
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Phosphodiesterase InhibitorsPhosphodiesterase Inhibitors
Work by inhibiting the enzyme phosphodiesteraseWork by inhibiting the enzyme phosphodiesterase Results in:Results in:
Positive inotropic responsePositive inotropic response Vasodilation Vasodilation
Two drugs (inodilators)Two drugs (inodilators) Inamrinone (Inocor) and milrinone (Primacor)Inamrinone (Inocor) and milrinone (Primacor)
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Phosphodiesterase Inhibitors:Phosphodiesterase Inhibitors:IndicationsIndications
Short-term management of heart failureShort-term management of heart failure Given when patient has not responded to treatment Given when patient has not responded to treatment
with digoxin, diuretics, and/or vasodilatorswith digoxin, diuretics, and/or vasodilators Often given as weekly 6-hour infusionsOften given as weekly 6-hour infusions
Improved quality of lifeImproved quality of life Decreased readmissions for heart failure episodesDecreased readmissions for heart failure episodes
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Phosphodiesterase Inhibitors:Phosphodiesterase Inhibitors:Adverse EffectsAdverse Effects
Inamrinone (Inocor)Inamrinone (Inocor) Thrombocytopenia, most worrisomeThrombocytopenia, most worrisome Dysrhythmia, nausea, hypotensionDysrhythmia, nausea, hypotension Elevated liver enzymes with long-term useElevated liver enzymes with long-term use
Milrinone (Primacor)Milrinone (Primacor) Dysrhythmia, mainly ventricularDysrhythmia, mainly ventricular Hypotension, angina, hypokalemia, tremor, Hypotension, angina, hypokalemia, tremor,
thrombocytopeniathrombocytopenia
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Cardiostimulatory DrugsCardiostimulatory Drugs
Enhance cardiac function by:Enhance cardiac function by: Increasing heart rateIncreasing heart rate Increasing myocardial contractilityIncreasing myocardial contractility Positive InotropPositive Inotrop
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Beta-adrenoceptor agonistsBeta-adrenoceptor agonists
Sympathomimetic drugs that bind to beta Sympathomimetic drugs that bind to beta receptors located in cardiac nodal tissue, receptors located in cardiac nodal tissue, conducting tissueconducting tissue
Beta-1 & beta-2 adrenoceptor activation Beta-1 & beta-2 adrenoceptor activation stimulates heart rate & contractilitystimulates heart rate & contractility
Net effect: Increase in cardiac outputNet effect: Increase in cardiac output Used to treat heart failure, cardiogenic and Used to treat heart failure, cardiogenic and
circulatory shockcirculatory shock
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Beta-AgonistsBeta-AgonistsCardiac EffectsCardiac Effects
Increase contractililtyIncrease contractililty
Increase heart rateIncrease heart rate
Increase conduction velocityIncrease conduction velocity
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Beta AgonistsBeta AgonistsVascular & Other EffectsVascular & Other Effects
Smooth muscle relaxationSmooth muscle relaxation BronchodilatationBronchodilatation Hepatic glycogenolysisHepatic glycogenolysis Pancreatic release of glucagonPancreatic release of glucagon Renin release by kidneyRenin release by kidney
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Beta-Agonist DrugsBeta-Agonist Drugs
EpinephrineEpinephrine Norepinephrine (Levophed)Norepinephrine (Levophed) DopamineDopamine DobutamineDobutamine IsoproterenolIsoproterenol
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Major Side EffectsMajor Side Effects
ArrhythmiasArrhythmias Increase myocardial demand for oxygenIncrease myocardial demand for oxygen Increase in heart rateIncrease in heart rate Can precipitate anginaCan precipitate angina
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B-type natriuretic peptide B-type natriuretic peptide
New classNew class Nesiritide ( Natrecor)Nesiritide ( Natrecor) Synthetic recombinant version of B-type Synthetic recombinant version of B-type
natriuretic peptidenatriuretic peptide Vasodilating effects on arteries and veinsVasodilating effects on arteries and veins Used in ICU setting as last alternativeUsed in ICU setting as last alternative
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Positive Inotropic Drugs:Positive Inotropic Drugs:Nursing ImplicationsNursing Implications
Assess history, drug allergies, Assess history, drug allergies, contraindicationscontraindications
Assess clinical parameters, including:Assess clinical parameters, including: BPBP Apical pulse for 1 full minuteApical pulse for 1 full minute Heart sounds, breath soundsHeart sounds, breath sounds
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Positive Inotropic Drugs:Positive Inotropic Drugs:Nursing Implications (cont’d)Nursing Implications (cont’d)
Assess clinical parameters (cont'd)Assess clinical parameters (cont'd) Weight, I&O measuresWeight, I&O measures EKGEKG Serum labs: potassium, sodium, magnesium, Serum labs: potassium, sodium, magnesium,
calcium, renal and liver function studiescalcium, renal and liver function studies
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Positive Inotropic Drugs:Positive Inotropic Drugs:Nursing Implications (cont’d)Nursing Implications (cont’d)
Before giving any dose, count apical pulse for Before giving any dose, count apical pulse for 1 full minute1 full minute
For apical pulse less than 60 or greater than For apical pulse less than 60 or greater than 120 beats/minute120 beats/minute Hold doseHold dose Notify prescriberNotify prescriber
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Positive Inotropic Drugs:Positive Inotropic Drugs: Nursing Implications (cont’d)Nursing Implications (cont’d)
Hold dose and notify prescriber if patient Hold dose and notify prescriber if patient experiences signs/symptoms of toxicityexperiences signs/symptoms of toxicity Anorexia, nausea, vomiting, diarrheaAnorexia, nausea, vomiting, diarrhea Visual disturbances (blurred vision, seeing green Visual disturbances (blurred vision, seeing green
or yellow halos around objects)or yellow halos around objects)
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Positive Inotropic Drugs: Positive Inotropic Drugs: Nursing Implications (cont’d)Nursing Implications (cont’d)
Check dosage forms carefully, and follow Check dosage forms carefully, and follow instructions for givinginstructions for giving
Avoid giving digoxin with high-fiber foods Avoid giving digoxin with high-fiber foods (fiber binds with digitalis)(fiber binds with digitalis)
Patients should report immediately a weight Patients should report immediately a weight gain of 2 or more pounds in 1 day or 5 or gain of 2 or more pounds in 1 day or 5 or more pounds in 1 weekmore pounds in 1 week
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Positive Inotropic Drugs: Positive Inotropic Drugs: Nursing Implications (cont’d)Nursing Implications (cont’d)
Inamrinone or MilrinoneInamrinone or Milrinone Use an infusion pumpUse an infusion pump Monitor I&O, heart rate, BP, daily weights, Monitor I&O, heart rate, BP, daily weights,
respirations, etc.respirations, etc. IV InamrinoneIV Inamrinone
Do not mix with dextroseDo not mix with dextrose Solution color is true yellowSolution color is true yellow
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Positive Inotropic Drugs: Positive Inotropic Drugs: Nursing Implications (cont’d) Nursing Implications (cont’d)
Monitor for therapeutic effectsMonitor for therapeutic effects Increased urinary outputIncreased urinary output Decreased edema, shortness of breath, dyspnea, Decreased edema, shortness of breath, dyspnea,
crackles, fatiguecrackles, fatigue Resolving of paroxysmal nocturnal dyspneaResolving of paroxysmal nocturnal dyspnea Improved peripheral pulses, skin color, Improved peripheral pulses, skin color,
temperaturetemperature Monitor for adverse effectsMonitor for adverse effects
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QuestionQuestion
When teaching the patient the signs and When teaching the patient the signs and symptoms of cardiac glycoside toxicity, the symptoms of cardiac glycoside toxicity, the nurse should alert the patient to watch for;nurse should alert the patient to watch for; A. Visual changes such as photophobiaA. Visual changes such as photophobia B. Flickering lights or halos around lightsB. Flickering lights or halos around lights C. dizziness when standing upC. dizziness when standing up D. Increased urine output D. Increased urine output
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QuestionQuestion
During assessment of a patient receiving During assessment of a patient receiving Digoxin, which finding would indicate an Digoxin, which finding would indicate an increased possibility of toxicity?increased possibility of toxicity? A. Apical rate of 62A. Apical rate of 62 B. Digoxin level of 1.5 ng/mlB. Digoxin level of 1.5 ng/ml C. Serum potassium level of 2 mEq/LC. Serum potassium level of 2 mEq/L D. Serum potassium level of 4.8 mEq/LD. Serum potassium level of 4.8 mEq/L
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QuestionQuestion
When monitoring a patient who is receiving When monitoring a patient who is receiving an IV infusion of Inocor, the nurse will look for an IV infusion of Inocor, the nurse will look for which adverse effect?which adverse effect? A. ThrombocytopeniaA. Thrombocytopenia B. ProteinuriaB. Proteinuria C. AnemiaC. Anemia D. Decreased BUN/Creatinine levelsD. Decreased BUN/Creatinine levels
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QuestionQuestion
When administering the daily dose of digoxin When administering the daily dose of digoxin 0.125mg PO to a patient with IDDM who is 0.125mg PO to a patient with IDDM who is now in heart failure, it is most important for now in heart failure, it is most important for the nurse to:the nurse to: A. Give medication with a class of orange juice.A. Give medication with a class of orange juice. B. Monitor the patient for dysrhythmias.B. Monitor the patient for dysrhythmias. C. Administer it 1 hour before the morning dose of C. Administer it 1 hour before the morning dose of
insulin.insulin. D. Withhold dose if the apical heart rate is less D. Withhold dose if the apical heart rate is less
then 80 beats per minute.then 80 beats per minute.
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Case ScenarioCase ScenarioHeart FailureHeart Failure
Mrs. Allen is a 76 year old female admitted Mrs. Allen is a 76 year old female admitted with heart failure. She has been started on with heart failure. She has been started on Digoxin 0.125 mg po. Your initial assessment Digoxin 0.125 mg po. Your initial assessment of this patient revealed the following:of this patient revealed the following:
AAOx1AAOx1 Vitals: P 110, RR 33, BP 110/56 SAO2 92%Vitals: P 110, RR 33, BP 110/56 SAO2 92% +2 pedal edema+2 pedal edema Bilateral basilar crackles, SOB on minimal Bilateral basilar crackles, SOB on minimal
exertionexertion
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Scenario con’tScenario con’t
Weight gain of 2 lbs over past 5 daysWeight gain of 2 lbs over past 5 days Urine output =240 ml/8 hr shiftUrine output =240 ml/8 hr shift