Ppt chapter 29

Chapter 29
Drugs Treating Heart Failure
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins

Question
• What is the normal amount of blood that is ejected from
the heart with each contraction?
– A. 45 mL
– B. 50 mL
– C. 75 mL
– D. 100 mL

Answer
• C. 75 mL
• Rationale: The amount of blood that is ejected from
the heart with each contraction is 75 mL. This is
referred to as the stroke volume.

Physiology
• The volume of blood that leaves the left ventricle in 1
minute is the cardiac output.
• Cardiac output consists of two elements, stroke volume
and heart rate.
• Stroke volume is the amount of blood that leaves the left
ventricle with each contraction.
• Stroke volume is dependent on three factors: preload,
contractility, and afterload.

Physiology (cont.)
• Contractility also is affected by the concentration of
catecholamines in the heart muscle.
• Peripheral resistance (PR) = pressure ´ diameter of
vessel.
• Contractions of the heart are dependent on the unique
electrical conduction system of the cardiac muscle.

Systemic Circulation

Pathophysiology
• Heart failure (HF) is associated with high morbidity and
high mortality.
• Pathologic processes that may cause HF occur either in
the heart itself or systemically.
• Cardiac output decreases when the left ventricle is
unable to eject its normal volume of blood during systole.
• The heart muscle enlarges (cardiomyopathy) to provide
more contractile force to try to improve cardiac output.

Pathophysiology (cont.)
• In HF, left-sided failure occurs first, then right-sided
failure.
• Natriuretic peptides are endogenous cardiac hormones.
Brain natriuretic peptide, working with atrial natriuretic
peptide, regulates cardiovascular homeostasis and fluid
volume.
• It is secreted primarily by the ventricular tissue in
response to changes in wall tension.

Classification of Heart Failure

Drugs to Treat Chronic Heart Failure
• When the heart cannot achieve the normal cardiac output
for various reasons, a backlog of blood, or congestion,
occurs, and heart failure develops.
• Several drug classes are used to treat CHF, and
polypharmacy is considered the standard and most
effective treatment.
• Research suggests that the clinical benefits of ACE
inhibitors and beta blockers are related to modifying the
changes that occur in the left ventricle with CHF.

Drugs to Treat Chronic Heart Failure
(cont.)
• Additionally, the following agents should be given to
selected patients: cardiac glycosides (digoxin),
aldosterone antagonists, ARBs, and the combination
vasodilator–antianginal (hydralazine–isosorbide) for black
patients.
• Drug therapy has been effective in increasing survival of
individuals with CHF.

Cardiac Glycosides
• The cardiac glycosides also are known as digitalis
preparations or digitalis glycosides.
• Digoxin is used to maintain clinical stability and improve
symptoms, quality of life, and exercise tolerance in
patients with all phases of CHF.
• Digoxin does not decrease mortality from CHF.
• Current AHA/ACC guidelines recommend that digoxin can
be added to reduce hospitalizations for HF or for rate
control if patients also have atrial fibrillation.

Cardiac Glycosides (cont.)
• Digoxin is not used as the primary treatment for
stabilizing patients with acute episodes of
noncompensated heart failure.
• Digoxin increases the force of cardiac contraction,
increasing cardiac output.
• Prototype drug: digoxin (Lanoxin)

Digoxin: Core Drug Knowledge
• Pharmacotherapeutics
– Used in the treatment of CHF and atrial fibrillation
• Pharmacokinetics
– Administered: oral and IV. Absorption: varies with
formulation of administration. Excreted: kidneys
• Pharmacodynamics
– It exerts an indirect effect on the heart from
stimulation of the autonomic nervous system and a
direct action on both the cardiac muscle and the
specialized electrical conduction system of the heart.

Digoxin: Core Drug Knowledge (cont.)
• Contraindications and precautions
– Heart block, ventricular fibrillation and
hypersensitivity
• Adverse effects
– Dysrhythmias, anorexia, nausea, vomiting, diarrhea,
headache, weakness, apathy, drowsiness, visual
disturbances, confusion, restlessness, disorientation,
seizures, delirium, hallucinations, neuralgia, and
psychosis
• Drug interactions
– Multiple drugs

Digoxin: Core Patient Variables
• Health status
– Assess cardiac rhythm, weight, and renal function.
• Life span and gender
– Determine pregnancy status and age.
• Lifestyle, diet, and habits
– Determine the patient’s normal dietary intake of
potassium, calcium, and magnesium.
• Environment
– Assess environment where drug will be given.

Digoxin: Nursing Diagnoses and Outcomes
• Decreased Cardiac Output related to altered cardiac
function
– Desired outcome: The patient’s CHF will be well
controlled.
• Risk for Injury related to drowsiness, confusion,
disorientation, seizures, delirium, hallucinations, and
psychosis secondary to adverse effects of drug therapy
– Desired outcome: The patient will not sustain an
injury related to adverse drug events while on drug
therapy.

Digoxin: Planning and Interventions
• Maximizing therapeutic effects
– Rapid onset of therapeutic effects; the patient is
digitalized with an IV or PO loading dose.
– Assess for therapeutic and adverse effects before
each dose.
• Minimizing adverse effects
– Digoxin has a narrow therapeutic index.
– It is important to monitor the serum levels of
digoxin.

Digoxin: Teaching, Assessment, and
Evaluations
• Patient and family education
– Explain the reason for taking digoxin and the adverse
effects of the drug.
– Teach patient how to monitor pulse.
– Discuss that OTC drugs can interact with digoxin.
• Ongoing assessment and evaluation
– Monitor the patient’s pulse rate throughout therapy.
– Symptoms of CHF should improve.

Question
• Digoxin has a wide therapeutic range.
– A. True
– B. False

Answer
• B. False
• Rationale: Digoxin has a very narrow therapeutic range.

Natriuretic Peptides
• The natriuretic peptide is a new class of drugs used to
treat CHF.
• Prototype drug: nesiritide (Natrecor)

Nesiritide: Core Drug Knowledge
• Pharmacotherapeutics
– Use in adults with acute, decompensated HF.
• Pharmacokinetics
– Administered: IV. Excreted: kidneys. Onset: rapid
• Pharmacodynamics
– Stimulates natriuretic peptide A/B receptors,
promoting smooth muscle cell relaxation and dilation
of veins and arteries

Nesiritide: Core Drug Knowledge (cont.)
• Contraindications and precautions
– Cardiogenic shock, hypersensitivity, and systolic
blood pressure less than 90 mm Hg
• Adverse effects
– Hypotension, injection site reactions, rash, sweating,
itching, leg cramps, anemia, confusion,
lightheadedness, dimmed vision, increased creatinine
levels, cough, apnea, and hemoptysis
– Serious side effects are all cardiac.
• Drug interactions
– Is known to interact with some drugs

Nesiritide: Core Patient Variables
• Health status
– Assess status of CHF and clinical symptoms.
• Life span and gender
– Determine age.
• Environment
– Administer the drug only where patients can receive
continuous cardiac monitoring.

Nesiritide: Nursing Diagnoses and
Outcomes
• Decreased Cardiac Output related to altered stroke
volume
– Desired outcome: drug therapy with nesiritide will
increase cardiac output.

Nesiritide: Planning and Interventions
• Maximizing therapeutic effects
– Nesiritide must be reconstituted and then further
diluted for infusion.
– Use the reconstituted nesiritide solution within 24
hours.
• Minimizing adverse effects
– Monitor the patient’s cardiac response to nesiritide
therapy by keeping the patient on a continuous
cardiac monitor during therapy.
– Monitor the patient’s blood pressure and pulse.

Nesiritide: Teaching, Assessment, and
Evaluations
• Patient and family education
– Teach patients and families the purpose of nesiritide
therapy.
– Instruct patients to notify a nurse if the IV insertion
site becomes sore or itches.
• Ongoing assessment and evaluation
– Monitor plasma brain natriuretic peptide
concentrations and plasma aldosterone levels, both
of which should decrease in response to the drug.

Question
• What is a significant side effect of nesiritide infusion?
– A. Respiratory depression
– B. Change in level of consciousness
– C. Seizures
– D. ECG changes

Answer
• D. ECG changes
• Rationale: Significant ECG or rhythm changes can
occur from nesiritide therapy. Therefore, administer
the drug only where patients can receive continuous
cardiac monitoring, such as in an intensive care or
cardiac care unit.

Ppt chapter 29

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