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TRANSCRIPT
Medications Affecting the Cardiovascular
System (CVS)
Drug therapy used to treat cardiovascular disorders
LEARNING OBJECTIVES:
• After studying the following lectures, the student should be
able to:
• Understand the different groups of drugs acting on the
CVS: antihypertensive, cardiotonic, antianginal,
antiarrhythmic and antihyperlipidemic drugs.
• Describe the general mechanisms of action of these drugs
• Name the common adverse effects, contraindication, and
interaction of drugs
• Identify nursing responsibilities when administering drugs
acting on the CVS
Drug therapy used to treat cardiovascular disorders:
Drugs Affecting Blood Pressure: Antihypertensive Drugs
Drugs used to treat Heart Failure: Cardiotonic Drugs
Drugs used to treat Coronary Artery Disease –myocardial
infarction & angina: Antianginal Drugs
Drugs used to treat Arrhythmias: Antiarrhythmic Drugs
Drugs used to treat Hyperlipidemia: Antihyperlipidemic
Drugs
Treatment of hypertension: Antihypertensive drugs Hypertension (HT): a common & chronic disorder.
• Primary or essential HT (90 – 95% of cases) – idiopathic of known
etiology and can be controlled with appropriate therapy – treatment does
not cure the disease it only reduce symptoms and maintaining the BP
within normal limits.
• Secondary HT (5 – 10% of cases) may result secondary to renal,
endocrine, or CNS disorders and from drugs that stimulate the
Sympathetic NS or cause retention of sodium and water – can
sometimes be cured by surgery
Management of Hypertension • To reduce BP two kinds of treatment may be used:
1.Non-drug therapy (lifestyle modification)
Before prescribing antihypertensive therapy, we must encourage
the patient to change his or her lifestyle
Benefit of lifestyle modification:
Appropriate lifestyle measures may
Obviate the need for drug therapy in patients with borderline HT
Reduce the dose and/or the number of drugs required in patients
with established HT
Directly increase the effectiveness of drugs
Reduce cardiovascular risk.
2.Antihypertensive Therapy • There are several different types of drugs that affect different areas of
blood pressure control may need to be used to maintain a patient’s
blood pressure within normal limits.
• Primary antihypertensive drugs class:
Diuretics
Drugs affecting the renin – angiotensin system
Calcium Channel Blockers
Beta adrenergic antagonists (blockers)
• Alternative antihypertensive drugs class:
Alpha1 adrenergic antagonists
Alpha2 adrenergic agonists
Direct acting vasodilators
Diuretics • They are important therapeutic agents widely used
because they can enhance the effects of other
hypotensive drugs, have few side effects, and useful in
preventing renal failure by their ability to sustain urine
flow.
• Major clinical indications for diuretics are edema,
heart failure, and hypertension.
• Diuretic therapy alone may used to treat mild –
moderate HT (very effective)
• In moderate or severe HT that does not respond to a
diuretic alone, the diuretic may be continued and
another antihypertensive drug added.
• Mechanism of action: Diuretics act at different sites in
the nephrons to decrease reabsorption and increase renal
excretion of water, sodium, and other electrolytes, thereby
increasing urine formation and urine output (Diuresis) →
blood volume↓→ cardiac output↓→ BP↓
Nursing Interventions Adverse Effects
• Instruct clients to change positions slowly and to lie
down if feeling dizzy, lightheaded, or faint. Orthostatic hypotension (especially with Loop diuretics
their sodium-losing effect being
up to 10 times greater than of
thiazide diuretics).
• Assess/monitor clients for signs of dehydration (dry
mouth, increased thirst, minimal urine output,
weight loss).
• Monitor electrolytes, weight and urine output
Dehydration
• Teach clients to recognize signs and symptoms of
hypokalemia (nausea/vomiting, general weakness).
• Monitor the client’s cardiac status and K+ levels
• This can be minimized by consuming foods high in
potassium, such as spinach, tomatoes, bananas,
potatoes & using K+ supplements or Potassium-
sparing diuretic.
Hypokalemia – K+ less
than 3.5 mEq/L
(because they are K+
wasting diuretic)
• Monitor clients for an increase in blood glucose
levels especially in DM patients Hyperglycemia
• Monitor clients for an increase in serum uric acid
levels Hyperuricemia
Drugs affecting the renin–angiotensin system • These drugs decrease BP and increase urine volume.
1. Angiotensin-Converting Enzyme (ACE) inhibitors
2. Angiotensin Receptor blockers.
Angiotensin-Converting Enzyme (ACE) inhibitors
• Eg Captopril (Capoten)
• Enalapril Lisinopril Benazapril ……
Angiotensin Receptor blockers
• Eg Lasortan Valsartan
• Candesartan, Irbesartan…..
• Both drug groups decrease BP and increase urine volume by :–
1) Produce arterial dilatation and lowering peripheral resistance
2) Dilates the veins and reduce venous return to the heart and
hence reduce cardiac output
3) Reduce aldosterone secretion increase water and sodium
excretion by the kidney decreasing blood volume
reduce cardiac output
Pharmacokinetic: • All ACE inhibitors given orally except Enalapril IV. These drugs
are rapidly absorbed and widely distributed.
• Drug should be taken on an empty stomach, 1 hr before or 2 hrs after meals – absorption of the drugs decreases if they are taken with foods.
• Metabolized in liver and excreted in urine & feces.
• They cross the placenta and enter breast milk. They should not be used during pregnancy (serious fetus abnormalities) and lactation (side effect in babies).
Therapeutic uses:
1.Treatment of HT--- alone or in combination with other drugs.
2. HF and left ventricular dysfunction
3. Myocardial infarction (to decrease mortality and to decrease risk of heart failure and left ventricular dysfunction)
4. Diabetic nephropathy – prevent or delay end stage renal disease in type I or type II diabetics.
Nursing Interventions Adverse Effects
• Start treatment with a low dosage of the medication.
When possible, administer the first dose at bedtime
to avoid 1st dose effect .
• Monitor the patient’s blood pressure for 2 hrs. after
initiation of treatment.
• Instruct patients to change positions slowly and to
lie down if feeling dizzy, lightheaded, or faint.
• If the patient is already taking a diuretic, the
medication should be stopped temporarily for 2 to 3
days prior to the start of an ACE inhibitor.
First-dose orthostatic
hypotension
• Inform patients of the possibility of experiencing a
dry cough (primarily with captopril) – sleep with
head elevated and to notify the provider. The
medication should be discontinued, if the cough
worsens.
Persistent dry cough related to inhibition of
kinase II (alternative name
for ACE) which results in
increase in bradykinin
Nursing Interventions Adverse Effects
• Monitor potassium levels to maintain a level
within the expected reference range of 3.5 to 5
mEq/L.
• Advise patients to avoid the use of salt substitutes
containing potassium.
Hyperkalemia
Monitor liver and kidney function – for any abnormality
• Patients should inform the provider if these effects
occur.
• Symptoms will stop with discontinuation of the
medication.
Hypersensitivity, GI
irritation, Ulcer, and
Constipation, Headache,
Dizziness,
• Monitor the client’s WBC counts every 2 weeks
for 3 months, then periodically.
• This condition is reversible when detected early.
• Inform clients to notify the provider at the first
signs of infection, (fever, sore throat) because
medication should be discontinued.
Neutropenia and other
blood dyscrasias (rare
but serious complication
of captopril)
Contraindication & caution
Presence of allergy to any of these drugs
Patient with impaired hepatic and renal function
During pregnancy (Pregnancy Risk Category D) and
lactation
Caution should be used in patient with CHF
Interaction:
Diuretics can contribute to first-dose hypotension.
Other antihypertensive drugs may have an additive
hypotensive effect.
K+ supplements and K+ – sparing diuretics increase the
risk of hyperkalemia.
Use of NSAIDs may decrease the antihypertensive effect of
ACE inhibitors. Avoid concurrent use.
Calcium Channel Blockers
• These drugs BP, cardiac workload and myocardial oxygen
consumption through following mechanism: blocking Ca+2 ion
channels in the heart and blood vessels prevent the movement
of Ca. into the cardiac and smooth muscle cells interferes with
the muscle cells ability to contract, leading to a loss of muscle
tone (negative inotropic effect), vasodilation, and a decrease in
peripheral resistance.
• Classification of Calcium Channel Blockers
− Selective (blood vessels) − E.g., Nifedipine (Adalat), Nicardipine , Felodipine,
Amlodipine
− Nonselective (blood vessels and heart)
− E.g., Verapamil, Diltiazem, Isradipine, Nisoldipine
Therapeutic uses: • HT Angina pectoris Dysrhythmia Reynaud's disease
Pharmacokinetic: • These drugs are rapidly absorbed, metabolized in liver and excreted in
urine. They cross the placenta and enter breast milk.
Contraindication & caution • Presence of allergy to any of these drugs
• Heart block
• Renal and hepatic dysfunction
• During pregnancy and lactation because of the potential for adverse
effects on the fetus or neonate
• These drugs interact with grapefruit juice. Advice the patient does not
take these drugs with grapefruit juice, which increases absorption of
these drugs from the GI tract.
• Verapamil increases plasma concentration of digoxin.
• B-blockers increases risk of AV block and HF.
Nursing Interventions Adverse Effects
Advise the patient to rise slowly
from a sitting or lying position to
prevent dizziness.
CNS effects: dizziness, light-
headedness, headache, fatigue
Observe for constipation & take
measures to reduce the incidence
of constipation.
GI effects: nausea, constipation,
Monitor liver function. Hepatic injury (hepatotoxicity)
Assess the patient for changes in
vital signs and symptoms that
could indicate CHF (shortness of
breath, increase peripheral edema)
CV effects: hypotension,
bradycardia, peripheral edema (not
sign of Na+ retention it disappears
by lying flat over night), MI, heart
block.
• Skin flushing and rash.
Beta-adrenergic blockers • These drugs lower systemic BP by decrease the heart rate and
contractility; thereby reduce C.O.P by blockade of B1
receptors.
• They reduce release of rennin by blockade of B1 receptors in
the kidney thereby reducing angiotensin II.
• The long-term use of beta-blockers reduces the peripheral
vascular resistance – by unknown mechanism.
• E.g. Atenolol Metrolol Propranolol
• At low doses, B-blockers are well tolerated and serious side
effects are uncommon. As the dosage increased, the side
effects can become numerous and potentially serious in
certain patients.
• Alpha1-adrenergic blockers: E.g. Doxazosin, Prazosin,
Terazosin
• Selective α1-adrenoceptors blockers lead to vasodilatation with less
tachycardia and reduction of blood pressure. These drugs are also useful in
benign prostatic hypertrophy (relaxation of the bladder sphincter)
• Adverse effects: postural hypotension, headache, dry mouth, dizziness,
impotence and skin rash
• Alpha2–adrenergic agonists: E.g. Clonidine,
Methyldopa (Aldomet):
• Drugs act within brainstem (CNS) to suppress sympathetic outflow to the
heart & blood vessels. The result vasodilation and reduced COP, thus help to
lower BP.
• These drugs cause sedation, dizziness, depression, headache & other CNS
effects, dry mouth and peripheral edema. Also can cause serious side effects
such as hepatotoxicity, hemolytic anemia, and granulocytopenia.
• These drugs are rarely prescribed except Methyldopa, which is sometime a
preferred agent for treating chronic HT of pregnancy because of its safety
profile. HT is the most common complication of pregnancy.
• Nursing consideration:
The role of the nurse in antihypertensive therapy involves
careful monitoring of the patients condition and providing
education.
Prior to therapy, obtain baseline ECG, heart rate, & BP. The
following tests should be done in all patients: serum
electrolytes, creatinine, blood urea, glucose, uric acid, and
cholesterol especially with patient taking diuretics.
During therapy, observe the patient for therapeutic effects
and monitor vital signs regularly – stop the drug if BP less
than 90/60 mmHg
Assess for the contraindicated conditions – assess for any
history of allergy to drug, pregnancy & lactation,….
• Nursing consideration:
Determine the potential nursing diagnoses related to drug
therapy and health problems that the drug might cause.
Planning: patient goals and expected outcomes including
specific interventions directed to solving or preventing the
problem
Intervention with continues observation to ensuring
therapeutic effects and minimizing adverse effects
Administer diuretics early in the day so sleep is not
interrupted by frequent urination.
Dosage of antihypertensive drugs should be low initially
and then gradually increased. This approach minimizes side
effects and permits baroreceptors to reset to a lower
pressure.
Monitor the patient for signs and symptoms of adverse
effects
Advise the patient to rise slowly from a sitting or lying
position to prevent dizziness.
Observe for IV infiltration (can cause tissue destruction).
Discontinue medication gradually (abrupt withdrawal of
drug may cause rebound hypertension and anxiety
Monitor intake and output. Weight the patient at the same
time each day (to monitor for fluid retention or edema)
Monitor liver and kidney function.
Monitor nutritional status: for patients taken potassium- wasting diuretics eat foods high in potassium (bananas, apricots, sweet potatoes, orange juices, kidney beans) and for patients taken potassium- sparing diuretics avoid these foods.
Evaluate the effectiveness of drug therapy by confirming that the patient goals and expected outcomes have been met
Lack of patient compliance is the major cause of treatment failure in antihypertensive therapy.
Compliance is difficult to achieve because: 1. HT has no symptoms so drug benefits are not obvious.
2. HT progresses slowly so patients think they can postpone treatment.
3. Treatment is complex and expensive, continues lifelong, and can cause side effects.