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.