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Drugs Affecting Cardiac and Renal Systems
Jan Bazner-Chandler
MSN, CNS, C-PNP, RN
Positive Inotropic Drugs
Chapter 21
Inotropic Drugs
Drugs that increase the force of myocardial contractions.
Chronotropic Drugs
Drugs that increase the rate at which the heat beats.
Dromotropic Drugs
Drugs that accelerate conduction.
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.
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
CAD
Heart Valve Disease
Endocarditis
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.
Heart Failure
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
Pitting Edema
Distended Jugular Vein
Drugs in first-line treatment
Digoxin Diuretics ACE Angiotension-converting enzyme
inhibitors
Cardiac Glycosides
Oldest and most effective group of cardiac drugs.
Comes from the plant “fox glove”.
Cardiac Glycosides or Digoxin Digoxin or Lanoxin is the only commonly
used digitalis glycoside.
digoxin (Lanoxin, Digitek)
Classification Pharmacologic: digitalis, glycoside
Classification Therapeutic: antiarrhythmic, inotropic
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 enters the cell in exchange for sodium. The calcium activates the contractile proteins and
increased myocardial contractility.
Administration
Can be given orally or IV IV peaks within 10 to 30 minutes PO peaks within 1 to 2 hours
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
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
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
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
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.
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.
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.
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
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.
Antianginal Drugs
Chapter 23
Coronary Arteries
Arteries that deliver oxygen to the heart muscle.
Coronary Arteries
Angina Pectoris
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
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
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
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
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
Classification Pharmacologic: nitrates Classification Therapeutic: antianginals
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 / decrease in HR
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
Sublingual Nitroglycerine
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.
Sustained Released Tablet
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.
Nitroglycerine Patch
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
Nitroglycerine Ointment
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
Side Effects
Dizziness Headache Hypotension Tachycardia Syncope
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
Blood Pressure Medications
ACE inhibitors: angiotension-converting enzyme inhibitors
Beta blockers Calcium channel blockers Diuretics Vasodilators: used in hypertensive crisis only
B-adrenergic Blockers
B-blockers (beta 1) Primary drug effect is related to the
cardiovascular system.
When Used
Angina Myocardial infarct Dysrhythmias Hypertension Used when a client has a combination of any
of the above diagnoses
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.
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.
Contraindications
Conductive disturbances Bronchial asthma Diabetes: blocks hypo-glycemic induced
tachycardia. Reduced metal alertness Peripheral vascular disease
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
Nursing Responsibilities
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
Three most common drugs used carvedilol or Coreg metoprolol or Lopressor atenolol or Tenormin
Clinical Pearl
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
Three chemical classifications phenylalkylamines benzothiazepines dihydrophyridines
Action
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
First line drugs used to treat Angina Hypertension Supraventricular tachycardia: cardiac dysrhythmia
One Important Consideration When Prescribing 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
Drug allergy Acute Myocardial Infarction (MI) Atrial ventricular block
Bradycardia Pacemaker
Hypotension
Adverse Effects
Cardiovascular: Hypotension Heart palpitations Tachycardia / bradycardia Heart Failure
ACE Inhibitors – Angiotensin Receptor Antagonists Lotensin Capoten Vasotec Accupril Altace Mavik
ACE inhibitors
Indication: used alone or with other agents in the
management of hypertension used in patients with congestive heart failure
Action: blocks the vasoconstrictor and aldosterone
producing effects of angiotensin II at various receptor sites, including vascular smooth muscle and the adrenal glands.
ACE Inhibitors
Therapeutic Effects: 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
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
Monitor blood pressure Monitor for signs of fluid overload
Monitor weight Edema Jugular distension Lung congestion
Monitor frequency of prescription refills to determine adherence
Most common side effect
Cough Hyperkalemia (due to decrease in secretion
of potassium) Metallic taste
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.
Vasodilators
Intravenous (IV) diazoxide and sodium nitroprusside are useful in managing hypertensive emergencies.
Blood pressure need to be brought down slowly.
Nursing Responsiblities
Monitor for adverse effects: Orthostatic hypotension Dizziness fatigue
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.