Transcript Positive Inotropic Drugs

Drugs Affecting Cardiac and
Renal Systems
Jan Bazner-Chandler
MSN, CNS, C-PNP, RN
Positive Inotropic Drugs
Chapter 21
Inotropic Drugs
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Drugs that increase the force of myocardial
contractions.
Chronotropic Drugs
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Drugs that increase the rate at which the heat
beats.
Dromotropic Drugs
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Drugs that accelerate conduction.
Heart Failure
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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.
Causes of Heart Failure
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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
CAD
Heart Valve Disease
Endocarditis
Heart Failure
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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.
Heart Failure
Signs and Symptoms of Heart Failure or
HF
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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
Pitting Edema
Distended Jugular Vein
Drugs in first-line treatment
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Digoxin
Diuretics
ACE Angiotension-converting enzyme
inhibitors
Cardiac Glycosides
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Oldest and most effective group of cardiac
drugs.
Comes from the plant “fox glove”.
Cardiac Glycosides or Digoxin
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Digoxin or Lanoxin is the only commonly
used digitalis glycoside.
digoxin (Lanoxin, Digitek)
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Classification Pharmacologic: digitalis,
glycoside
Classification Therapeutic: antiarrhythmic,
inotropic
Actions
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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 enters the cell in exchange for sodium.
The calcium activates the contractile proteins and
increased myocardial contractility.
Administration
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Can be given orally or IV
IV peaks within 10 to 30 minutes
PO peaks within 1 to 2 hours
Serum Blood Levels
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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
Maintenance Dose
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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
Dosing by mcg/kg in Adults
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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
Nursing Responsibilities
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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
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Adults: apical pulse less than 60
Older child: apical pulse less than 60
Infant or younger child: apical pulse less than 100
Nursing Responsibilities
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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.
Laboratory Values
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Electrolyte imbalance: potassium, calcium
and magnesium values need to be monitored
Hypokalemia (low potassium)
Hypomagnesemia (low magnesium)
Both can lead to irregular heart rate.
Digoxin Toxicity
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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.
Evaluation of Effectiveness
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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
digoxin Overdose
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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.
Antianginal Drugs
Chapter 23
Coronary Arteries
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Arteries that deliver oxygen to the heart
muscle.
Coronary Arteries
Angina Pectoris
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Chest pain occurring when the heart’s supply
of blood carrying oxygen and energy-rich
nutrients is insufficient to meet demands of
the heart.
Ischemia
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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
Angina
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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
Angina
Angina
Classification of Angina
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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.
Antianginal Drugs
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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.
nitroglycerine
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Classification Pharmacologic: nitrates
Classification Therapeutic: antianginals
nitroglycerine
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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:
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Relief or prevention of anginal attacks
Reduction of blood pressure
Increase blood flow to heart / decrease in HR
Dosing
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Oral dosage is rapidly metabolized in the liver and
only small doses reach the systemic circulatory
system
For more effective absorption drug is given:
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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
Sublingual Nitroglycerine
Sublingual Administration
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Tablet should be held under tongue until
dissolved. Avoid eating, drinking, or smoking
until tablet is dissolved.
Acute anginal attacks:
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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.
Sustained Released Tablet
Sustained Released Tablet
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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.
Nitroglycerine Patch
Nitroglycerin Patch
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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
Nitroglycerine Ointment
Nitroglycerine Ointment
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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
Side Effects
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Dizziness
Headache
Hypotension
Tachycardia
Syncope
Antiaginal Drugs
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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
Blood Pressure Medications
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ACE inhibitors: angiotension-converting
enzyme inhibitors
Beta blockers
Calcium channel blockers
Diuretics
Vasodilators: used in hypertensive crisis only
B-adrenergic Blockers
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B-blockers (beta 1)
Primary drug effect is related to the
cardiovascular system.
When Used
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Angina
Myocardial infarct
Dysrhythmias
Hypertension
Used when a client has a combination of any
of the above diagnoses
Action of Beta 1 Blockers
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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.
Contraindications
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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.
Contraindications
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Conductive disturbances
Bronchial asthma
Diabetes: blocks hypo-glycemic induced
tachycardia.
Reduced metal alertness
Peripheral vascular disease
Adverse Effects
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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
Nursing Responsibilities
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Monitor blood pressure
Assess for orthostatic hypotension when a
client stands up
Check medication refills for adherence
Assess for angina
Monitor for signs of overdose
Beta Blocker Drugs
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Three most common drugs used
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carvedilol or Coreg
metoprolol or Lopressor
atenolol or Tenormin
Clinical Pearl
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Beta blockers are good to use in clients who
like to exercise.
It does not allow the heart rate to elevate to
dangerous levels
Client may report inability to generate a
increase heart rate while exercising
Calcium Channel Blockers
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Three chemical classifications
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phenylalkylamines
benzothiazepines
dihydrophyridines
Action
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Block calcium entry into cells of vascular
smooth muscle an myocardium. Dilate
coronary arteries in both normal and ischemic
myocardium and inhibit coronary artery
spasm.
Increased blood flow to ischemic heart
Useful in treating dysrhythmias
Indications
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First line drugs used to treat
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Angina
Hypertension
Supraventricular tachycardia: cardiac dysrhythmia
One Important Consideration When
Prescribing
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Calcium Channel Blockers 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.
Contraindications
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Drug allergy
Acute Myocardial Infarction (MI)
Atrial ventricular block
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Bradycardia
Pacemaker
Hypotension
Adverse Effects
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Cardiovascular:
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Hypotension
Heart palpitations
Tachycardia / bradycardia
Heart Failure
ACE Inhibitors – Angiotensin
Receptor Antagonists
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Lotensin
Capoten
Vasotec
Accupril
Altace
Mavik
ACE inhibitors
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Indication:
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used alone or with other agents in the
management of hypertension
used in patients with congestive heart failure
Action:
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blocks the vasoconstrictor and aldosterone
producing effects of angiotensin II at various
receptor sites, including vascular smooth muscle
and the adrenal glands.
ACE Inhibitors
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Therapeutic Effects:
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Lowering of blood pressure
Decreased after load in patients with Congestive
Heart Failure
Decreased development of Heart Failure
Increased survival after Myocardial infarct
Decreased progression of diabetic neuropathy
Evaluation of Effectiveness
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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)
Nursing Responsibilities
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Monitor blood pressure
Monitor for signs of fluid overload
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Monitor weight
Edema
Jugular distension
Lung congestion
Monitor frequency of prescription refills to
determine adherence
Most common side effect
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Cough
Hyperkalemia (due to decrease in secretion
of potassium)
Metallic taste
Vasodilators
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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.
Vasodilators
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Intravenous (IV) diazoxide and sodium
nitroprusside are useful in managing
hypertensive emergencies.
Blood pressure need to be brought down
slowly.
Nursing Responsiblities
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Monitor for adverse effects:
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Orthostatic hypotension
Dizziness
fatigue
Nursing Assessment
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Monitor effectiveness of the drug therapy
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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.