Drugs Affecting Cardiac and Renal Systems

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Drugs Affecting Cardiac and Renal Systems

• Jan Bazner-Chandler
• MSN, CNS, C-PNP, RN

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Positive Inotropic Drugs

• Chapter 21

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Inotropic Drugs

• Drugs that increase the force of myocardial
  contractions.

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Chronotropic Drugs

• Drugs that increase the rate at which the heat
  beats.

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Dromotropic Drugs

• Drugs that accelerate conduction.

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Heart Failure

• Congestive heart failure (CHF), or heart failure
  (HF), is a condition in which the heart can't
  pump enough blood to the body's other organs.

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Causes of Heart Failure

• narrowed arteries that supply blood to the heart
  muscle  coronary artery disease (CAD)
• past heart attack, or myocardial infarction (MI),
  with scar tissue that interferes with the heart
  muscle's normal work
• high blood pressure
• heart valve disease
• primary disease of the heart muscle itself,
  called cardiomyopathy.
• heart defects present at birth  congenital heart
  defects.
• infection of the heart valves and/or heart muscle
  itself  endocarditis and/or myocarditis

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CAD
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Heart Valve Disease
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Endocarditis
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Heart Failure

• As blood flow out of the heart slows, blood
  returning to the heart through the veins backs
  up, causing congestion in the tissues. Often
  swelling (edema) results. Most often there's
  swelling in the legs and ankles, but it can
  happen in other parts of the body, too. Sometimes
  fluid collects in the lungs and interferes with
  breathing, causing shortness of breath,
  especially when a person is lying down.

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Heart Failure
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Signs and Symptoms of Heart Failure or HF

• Often no symptoms at rest
• Dyspnea (difficulty breathing) and fatigue occur
  with increased activity
• Edema of ankles and feet
• Distention of jugular veins
• In acute cases pulmonary edema cough and
  shortness of breath

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Pitting Edema
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Distended Jugular Vein
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Drugs in first-line treatment

• Digoxin
• Diuretics
• ACE Angiotension-converting enzyme inhibitors

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Cardiac Glycosides

• Oldest and most effective group of cardiac drugs.
• Comes from the plant fox glove.

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Cardiac Glycosides or Digoxin

• Digoxin or Lanoxin is the only commonly used
  digitalis glycoside.

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digoxin (Lanoxin, Digitek)

• Classification Pharmacologic digitalis,
  glycoside
• Classification Therapeutic antiarrhythmic,
  inotropic

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Actions

• Digoxin improves the pumping ability of the heart
• Increases the force of myocardial contraction by
  inhibiting the Na, K-adenosine triphosphatase,
  an enzyme in cardiac cell membrane that decreases
  the movement of sodium out of myocardial cell
  after contraction.
• Calcium enter the cell in exchange for sodium.
• The calcium activates the contractile proteins
  and increased myocardial contractility.

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Administration

• Can be given orally or IV
• IV peaks within 10 to 30 minutes
• PO peaks within 1 to 2 hours

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Serum Blood Levels

• Maximum drug action occurs when steady tissue
  concentration has been achieved takes about 1
  week
• Loading dose or digitalizing dosage will be
  higher until the therapeutic level has been
  reached.
• Dosage 0.75 to 1.5 mg every 6 to 8 hours
• When adequate levels have been reached than a
  maintenance dose can be started

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Maintenance Dose

• Dosing is 0.125 0.5 mg
• Average dose is 0.25 mg
• Take daily at same time of day
• Give with food or after meals

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Dosing by mcg/kg in Adults

• IV digitalizing dose 0.6 to 1 mg (10 -15
  mcg/kg) given at 50 initially and additional
  fractions given at 4-8 hour intervals.
• PO adults digitalizing dose 0.75 1.25 mg (10
  15 mcg/kg)
• PO children digitalizing dose 10 to 15 mcg/kg

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Nursing Responsibilities

• Take apical pulse for one full minute before
  giving the medication listen for any irregular
  heart beats
• Specific guidelines for holding the drug and
  notifying physician
• Adults apical pulse less than 60
• Older child apical pulse less than 60
• Infant or younger child apical pulse less than
  100

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Nursing Responsibilities

• Notify physician if bradycardia (heart rate less
  than 60 bpm) or new arrhythmias occur.
• Assess for peripheral edema and auscultate lungs
  for rales/crackles.
• Check kidney function since you want to know they
  can excrete excess digoxin and avoid build up in
  body.

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Laboratory Values

• Electrolyte imbalance potassium, calcium and
  magnesium values need to be monitored
• Hypokalemia (low potassium)
• Hypomagnesemia (low magnesium)
• Both can lead to irregular heart rate.

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Digoxin Toxicity

• Anorexia, nausea, and confusion are symptoms of
  digoxin toxicity
• HR below 60 in adults and HR below100 in infants
  and small children
• Digoxin should be discontinued by MD only takes
  about 1 week for drug to be eliminated from the
  body.

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Evaluation of Effectiveness

• Increased urinary output
• Decreased edema
• Decreased shortness of breath, dyspnea and
  crackles
• Decreased fatigue
• Improved peripheral pulses, skin color and
  temperature
• Serum digoxin levels 0.5 to 2 ng/mL

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digoxin Overdose

• digoxin immune Fab or DigiFab
• Therapeutic classification antidotes
• Pharmacologic classification antibody fragments
• Indications serious life-threatening over dosage
  with digoxin.
• Action An antibody produced in sheep that binds
  anti-genetically to unbound digoxin in serum.
• Therapeutic effect Binding and subsequent
  removal of digoxin, preventing toxic effects in
  overdose.

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Antianginal Drugs

• Chapter 23

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Coronary Arteries

• Arteries that deliver oxygen to the heart muscle.

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Coronary Arteries
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Angina Pectoris

• Chest pain occurring when the hearts supply of
  blood carrying oxygen and energy-rich nutrients
  is insufficient to meet demands of the heart.

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Ischemia

• Poor blood flow to an organ
• Ischemic heart disease poor blood flow to heart
• Myocardial infarct damage done to heart muscle
  after an ischemic event

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Angina

• Angina pectoris is a clinical symptoms
  characterized by episodes of chest pain.
• There is deficit in myocardial oxygen supply
  (myocardial ischemia) in relation to myocardial
  oxygen demand.
• Pain can be caused by coronary vasospasm

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Angina
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Angina
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Classification of Angina

• Class I ordinary physical activity does not
  cause angina strenuous activity only.
• Class II angina occurs with walking or climbing
  stairs rapidly or up hill.
• Class III marked limitation in ordinary daily
  activity.
• Class IV anginal symptoms may be present at rest.

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Antianginal Drugs

• Nitrates are used to treat and prevent attack of
  angina.
• Only nitrates can be used in the acute treatment
  of angina pectoris.
• Calcium channel blockers and beta blockers are
  used prophylactically (to prevent) or in
  long-term management of angina.

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nitroglycerin

• Most widely used nitrate
• Antianginal
• Used to relieve acute angina

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nitroglycerine

• Classification Pharmacologic nitrates
• Classification Therapeutic antianginals

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nitroglycerine

• Action Increases coronary blood flow by dilating
  coronary arteries and improving collateral flow
  to ischemic regions. Decreases left ventricular
  end-diastolic pressure and left ventricular
  end-diastolic volume. Reduces myocardial oxygen
  consumption.
• Therapeutic effects
• Relief or prevention of anginal attacks
• Reduction of blood pressure
• Increase blood flow to heart

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Dosing

• Oral dosage is rapidly metabolized in the liver
  and only small doses reach the systemic
  circulatory system
• For more effective absorption drug is given
• Sublingually under the tongue acts in 1 to 3
  minutes
• PO sustained-released tablet
• Transdermal ointments applied on hairless area
  on back, chest or upper arm
• Patches takes 40 minutes to an hour to start
  working

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Sublingual Nitroglycerine
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Sublingual Administration

• Tablet should be held under tongue until
  dissolved. Avoid eating, drinking, or smoking
  until tablet is dissolved.
• Acute anginal attacks
• Advise patient to sit down.
• Relief should occur in 1 to 3 minutes
• May be repeated every 5 minutes for 3 doses.
• If no relief call 911.

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Sustained Released Tablet
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Sustained Released Tablet

• Administer dose 1 hour before or 2 hours after
  meal with a full glass of water for faster
  absorption.
• Note Sustained released preparations should be
  swallowed whole, do not crush, break or chew.

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Nitroglycerine Patch
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Nitroglycerin Patch

• Place the patch on a hairless area of chest or
  upper arm each day.
• Move patch to a different place on your body each
  day to prevent skin irritation.
• Remove the patch for 8 to 12 hours each night and
  put on a fresh patch each day.
• Do not leave on all the time.
• Remove for defibrillation

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Nitroglycerine Ointment
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Nitroglycerine Ointment

• Comes with paper with a ruled line for measuring
  the dose
• Squeeze ointment onto the paper, carefully
  measuring the amount specified on the
  prescription label
• Use the paper to spread ointment in a thin layer
  on a hair-free area of skin (2 by 3 inches)
• Keep paper in place with bandage or tape
• Ointment is applied three or four times a day

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Side Effects

• Dizziness or light-headedness
• Flushing of face and neck
• Increased heart rate
• Restlessness
• Rare side effects
• Blurred vision
• Dry mouth
• Weakness
• Fatigue

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Antiaginal Drugs

• Nitrates to manage the chest pain
• Beta blockers to manage the chest pain plus
  hypertension
• Calcium channel blockers to manage the chest pain
  plus hypertension

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Blood Pressure Medications

• ACE inhibitors angiotension-converting enzyme
  inhibitors
• Beta blockers
• Calcium channel blockers
• Diuretics
• Vasodilators used in hypertensive crisis only

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B-adrenergic Blockers

• B-blockers (beta 1)
• Primary drug effect is related to the
  cardiovascular system.

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When Used

• Angina
• Myocardial infarct
• Dysrhythmias
• Hypertension
• Used when a client has a combination of any of
  the above diagnoses

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Action of Beta 1 Blockers

• Decrease energy demands on heart to decrease
  angina attacks.
• Block the B receptors on the SA node to slow
  heart rate
• Block the harmful release of catecholamines
  (epinephrine and norepinephrine)
• Blocks the release of renin a potent
  vasoconstrictor in the kidney to decrease blood
  pressure.

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Contraindications

• Systolic heart failure
• Systolic cardiac (heart) dysfunction (or systolic
  heart failure) occurs when the heart muscle
  doesn't contract with enough force, so there is
  not enough oxygen-rich blood to be pumped
  throughout the body.

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Contraindications

• Conductive disturbances
• Bronchial asthma
• Diabetes blocks hypo-glycemic induced
  tachycardia.
• Reduced metal alertness
• Peripheral vascular disease

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Adverse Effects

• Decrease in HR blow the 60 bpm
• Decreased cardiac output
• Bronchocontriction in patients with asthma or
  COPD.
• Cardiac rhythm problems due to decreased SA or AV
  node conduction
• Hypo or hyperglycemia
• Hypotension

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Nursing Responsibilities

• Monitor blood pressure
• Assess for orthostatic hypotension when a client
  stands up
• Check for refills for adherence
• Assess for angina
• Monitor for signs of overdose

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Beta Blocker Drugs

• Three most common drugs used
• carvedilol or Coreg
• metoprolol or Lopressor
• atenolol or Tenormin

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Clinical Pearl

• Beta blockers are good to use in clients who like
  to exercise.
• Problem it does not allow the heart rate to
  elevate to dangerous levels
• Client may report inability to generate a
  increase heart rate while exercising

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Calcium Channel Blockers

• Three chemical classifications
• Phenylalkylamines
• Benzothiazepines
• Dihydrophyridines

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Action

• Prevents calcium from entering into contraction
  process of the heart thus promoting smooth muscle
  relaxation and coronary artery dilation.
• Increased blood flow to ischemic heart
• Useful in treating dysrhythmias

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Indications

• First line drugs used to treat
• Angina
• Hypertension
• Supraventricular tachycardia cardiac dysrhythmia

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One Important Consideration When Prescribing

• May not be as effective in controlling exercise
  induced elevation of heart rate or blood
  pressure.
• A beta 1 blocker would be best for the client
  that exercises drug would keep heart rate and
  blood pressure from rising during exertion.

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Contraindications

• Drug allergy
• Acute Myocardial Infarction (MI)
• Atrial ventricular block
• Bradycardia
• Pacemaker
• Hypotension

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Adverse Effects

• Cardiovascular
• Hypotension
• Heart palpitations
• Tachycardia / bradycardia
• Heart Failure

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ACE Inhibitors

• Lotensin
• Capoten
• Vasotec
• Accupril
• Altace
• Mavik

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ACE inhibitors

• Indication
• used alone or with other agents in the management
  of hypertension
• used in patients with congestive heart failure
• Action
• blocks the conversion of angiotension II
• inactivates the vasodilator bradykinin and other
  vasodilatory prostaglandins

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ACE Inhibitors

• Therapeutic Effects
• Lowering of blood pressure
• Decreased after load in patients with CHF
• Decreased development of HF
• Increased survival after MI
• Decreased progression of diabetic neuropathy

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Evaluation of Effectiveness

• Decrease in blood pressure
• Decrease in signs and symptoms of CHF
• Reduction of risk of developing CHF (congestive
  heart failure) after a MI (myocardial infarct)

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Nursing Responsibilities

• Monitor blood pressure
• Monitor for signs of fluid overload
• Monitor weight
• Edema
• Jugular distension
• Lung congestion
• Monitor frequency of prescription refills to
  determine adherence

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Vasodilators

• Action works directly on arteriolar and venous
  muscles to cause relaxation.
• Very useful in managing hypertensive emergencies.
• Blood pressure needs to be brought down slowly.

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Vasodilators

• Intravenous (IV) diazoxide and sodium
  nitroprusside are useful in managing hypertensive
  emergencies.

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Nursing Responsiblities

• Monitor for adverse effects
• Orthostatic hypotension
• Dizziness
• fatigue

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Nursing Assessment

• Monitor effectiveness of the drug therapy
• Client will return to baseline activities
• Client will report improved energy.
• Blood pressure reading will be lowered with the
  goal to bring back to normal levels.

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Effectiveness of Antihypertensive Agents in Black
Patients
Source Hall, 1990