CHAPTER 23
DRUGS FOR HYPERTENSION
LEARNING OUTCOME 1
Explain how hypertension is classified.
Concepts
1. Cardiovascular disease (CVD) includes conditions of the heart and blood vessels, and hypertension is the
most common form of CVD. It is the most frequent cause of death in the United States. Hypertension is the
consistent elevation of systemic arterial blood pressure. Multiple measurements of the blood pressure (B/P)
are taken over several visits to the physician to make an accurate diagnosis. Sustained systolic B/P of greater
than 140 mmHg or diastolic pressure greater than 90–99 mmHg constitutes a diagnosis of hypertension.
(See Table 23.1.)
2. Hypertension is classified into three categories: prehypertension, Stage 1, and Stage 2. There are key
elements that identify one stage from another: Prehypertension is classified as 120 to 139 mmHg/80 to 89
mmHg; Stage 1 hypertension as 140 to 159 mmHg/90 to 99 mmHg; and Stage 2 hypertension as 160 or
higher/100 or higher.
3. Blood pressure changes throughout the lifespan. What is considered normal blood pressure at one age can
be considered abnormal as we age.
Table 23.1 Classification and Management of Hypertension in Adults
LEARNING OUTCOME 2
Summarize the long-term consequences of untreated hypertension.
Concepts
1. Untreated hypertension affects four target organs: the heart, brain, kidneys, and retina.
2. The workload of the heart is increased due to untreated hypertension, resulting in heart failure. Blood vessel
damage occurs from untreated hypertension resulting in decreased blood and oxygen to the brain,
potentially resulting in transient ischemic attack or cerebral vascular accident. Vessels damaged in the
kidneys from untreated hypertension lead to progressive loss of function of the renal system. Visual
impairment and blindness result from damage to the vessels supplying blood to the retina.
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LEARNING OUTCOME 3
Explain the effects of cardiac output, peripheral resistance, and blood volume on blood pressure.
Concepts
1. The three factors responsible for creating blood pressure are cardiac output, peripheral resistance, and blood
volume. Cardiac output is the volume of blood pumped per minute. Higher cardiac output yields higher
blood pressure. Stroke volume (amount of blood pumped by contraction of the ventricles) and heart rate
determine cardiac output. Medications that affect cardiac output, stroke volume, and heart rate will
influence the patient’s blood pressure.
2. Peripheral resistance is the friction in the arteries as blood flows through the vascular system. Greater
resistance in the arteries yields higher blood pressure. Medications that affect vascular smooth muscles may
lower or raise the blood pressure. The autonomic nervous system also plays a role in controlling peripheral
resistance. Refer to Chapter 13.
3. Blood volume is the total amount of blood in the vascular system. Increased blood volume (i.e., intravenous
fluids) yields higher blood pressure. Medications that affect blood volume may lower or raise the blood
pressure.
LEARNING OUTCOME 4
Discuss how the vasomotor center, baroreceptors, chemoreceptors, emotions, and hormones influence blood
pressure.
Figure 23.3 Nervous and Hormonal Factors Influencing Blood Pressure
Concepts
1. The central and autonomic nervous systems are involved in regulating blood pressure. (See Figure 23.3.) In
the medulla oblongata, the vasomotor center sends nerve impulses to smooth muscle in arteries to either
constrict or relax, thereby constantly regulating blood pressure. Baroreceptors in the aorta and carotid
arteries sense pressure changes in these arteries and relay this information to the vasomotor center.
Chemoreceptors detect oxygen, carbon dioxide, and pH levels in the blood and relay this information to the
vasomotor center. The vasomotor center reacts by raising or lowering blood pressure according to the
information received.
2. Emotions are involved in regulating blood pressure. Blood pressure is increased by anger and stress and is
decreased by depression and lethargy.
3. The endocrine system is involved in regulating blood pressure. (See Figure 23.3.) Natural hormones affect
blood pressure on a daily basis. Epinephrine and norepinephrine injections cause vasoconstriction and raise
blood pressure. Antidiuretic hormone causes vasoconstriction and raises blood pressure by raising blood
volume.
Ch 23-2
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LEARNING OUTCOME 5
Discuss the role of therapeutic lifestyle changes in the management of hypertension.
Concepts
1. Assessment of patient’s lifestyle to identify any personal habits that may be affecting the patient’s blood
pressure is needed to give proper education on the treatment and/or prevention of hypertension. Personal
habits may include the patient’s dietary habits and exercise/activity regimen, as well as use of any
medication.
2. Genetics as well as environmental factors may contribute to the patient’s risk for hypertension. Our race,
gender, and family history of hypertension may contribute to a diagnosis of hypertension. Environmental
factors that may contribute to the patient’s risk for hypertension are tobacco use, high-fat diets, obesity,
excessive sodium intake or alcohol consumption, and a sedentary lifestyle.
3. Losing weight can help control or prevent hypertension. The loss of only ten to twenty pounds may
significantly lower blood pressure. Limiting foods high in fat and cholesterol can reduce serum-lipid levels,
resulting in decreasing body weight and blood pressure. Limiting sodium, tobacco, and alcohol to
recommended levels or stopping the intake of any of the above may help reduce the risk of hypertension
and/or lower the patient’s present blood pressure. Beginning an exercise program will also help.
LEARNING OUTCOME 6
Differentiate between drug classes used for the primary treatment of hypertension and those secondary agents
reserved for persistent hypertension.
Concepts
1. Primary antihypertensive agents:
Diuretics: These are the first drug of choice; they have few side effects and are effective in treating mild
and moderate hypertension as well as heart failure.
Angiotensin-converting enzyme (ACE) inhibitors: These medications, with the angiotensin II receptor
blockers, assist the body’s own mechanism to control blood pressure and fluid balance. ACE inhibitors
cause intense vasoconstriction and lower the blood pressure.
Angiotensin II receptor blockers: This class of medication also affects the hormone aldosterone from the
adrenal cortex. This increases sodium reabsorption in the kidneys and aids in retention of fluid in the
blood vessels, thereby increasing blood pressure.
Beta-adrenergic antagonists: These affect the vasomotor center and the sympathetic nervous system to
control blood pressure.
Calcium channel blockers: These drugs have emerged as a primary choice in the treatment of hypertension
and other cardiovascular diseases. They are used for individuals who do not respond well to other
pharmacological choices.
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Ch 23-3
2. Secondary antihypertensive agents:
Alpha1-adrenergic antagonists: These affect the sympathetic ner vous system’s control of the blood
pressure by blocking the sympathetic receptors in the arterioles, thereby causing the vessels to dilate.
Alpha2-adrenergic agonists: These drugs decrease the outflow of sympathetic nerve impulses from the
central nervous system to the heart and arterioles. This has the same effect as the alpha1.
Direct-acting vasodilators: These directly affect vascular smooth muscle, which lowers blood pressure.
This class has many side effects and is used for the hypertensive crisis.
Table 23.2 Combination Drugs for Hypertension
LEARNING OUTCOME 7
Describe the nurse’s role in the pharmacologic management of patients receiving drugs for hypertension.
Concepts
1. The role of the nurse in managing a patient with hypertension is to obtain a complete health history,
including allergies, drug history, and possible drug interactions. Obtain vital signs for a baseline and to
compare with previously obtained vital signs. A good physical assessment should be done, and blood and
urine specimens need to be obtained for analysis.
2. Diuretics: Key areas for the nurse to monitor with the use of nonpotassium-sparing diuretics include
orthostatic hypotension; laboratory electrolyte values and daily weights; potassium levels; increased weight
of more than two pounds in 24 hours; intake and output assessment of edema and heart and lung sounds for
signs of fluid overload. The patient’s ability to safely ambulate to the bathroom should be assessed, since
diuretics increase urination. The patient should also be aware of the side effect of photosensitivity and of the
possible need to increase potassium in the diet or with supplements.
For a potassium-sparing diuretic, teach the patient to limit the use of salt substitutes and potassium-rich
foods. Also, pregnant and lactating women should not take these types of diuretics. Patients with a history of
gout and kidney stones should be monitored closely. Key areas for the nurse to monitor include uric acid
levels and gynecomastia and hirsutism for spironolactone (Aldactone).With the use of thiazide-like
diuretics, key areas to monitor include laboratory values (potassium, sodium, calcium, magnesium, CBC,
BUN, creatinine, and serum lipids); blood-glucose levels in diabetics, since these drugs may cause
hyperglycemia; uric-acid levels. Patients should increase potassium because these are not potassium-sparing
drugs. The nurse should assess the patient for pregnancy and lactation, systemic lupus erythematosus, and
the use of digoxin; these medications should be avoided in patients with these conditions, or patients should
be monitored more closely. For loop diuretics, the nurse should monitor these key areas: severe potassium
loss; hypovolemia; hypotension; hearing loss (these drugs are ototoxic); glucose and uric acid levels.
3. Calcium channel blockers (CCBs): Key areas for the nurse to assess include the following: ECG, heart
rate, and blood pressure prior to therapy, since CCBs affect the coronary arteries and myocardial
contractility; during therapy the nurse should monitor heart rate and blood pressure regularly; health history
specific for heart dysrhythmias, because these drugs are contraindicated with some dysrhythmias; assess for
signs of CHF and reflex tachycardia since some CCBs reduce myocardial contractility; with IV
administration, tachycardia and hypotension are more pronounced; assess for pregnancy since CCBs are a
category C for pregnancy; dizziness, headache, and flushing are minor side effects. The nurse should teach
the patient to avoid drinking grapefruit juice because it increases the absorption of these drugs.
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4. Renin-angiotensins: Key areas for the nurse to assess and monitor include the following: baseline vital
signs; hypotension, because ACE inhibitors given for the first time or by the IV route can cause a severe
drop in blood pressure; angiodema, a serious side effect of ACE inhibitors, which can cause laryngeal
swelling, leading to asphyxia; lab values and signs of infection for the serious side effect of neutropenia or
agranulocytosis; potassium levels for hypokalemia, especially in patients with CHF, impaired kidney
function, and diabetes. Less serious side effects to monitor for include dizziness, light-headedness,
headache, and a tickling nonproductive cough; pregnancy-risk category D.
5. Adrenergic antagonists: Key areas for the nurse to assess and monitor include the following: baseline vital
signs and blood pressure response; hold the medication for pulse below 60 beats per minute and B/P below
90/60; monitor cardiac response through ECG, heart rate, and rhythm; assess for bradycardia, which may be
an indication of heart block; orthostatic hypertension and other minor side effects, such as dizziness, nausea,
and dry mouth. In order to avoid the complication of rebound hypertension, administration of adrenergic
antagonists should not be stopped abruptly. Diabetic patients taking these drugs may experience
hypoglycemia without exhibiting signs or symptoms, so fingerstick blood-sugar levels should be assessed
regularly. Patients taking alpha1 drugs should be monitored specifically for GI complaints, and elderly
patients should be assessed for hypothermic effects related to the vasodilation of these drugs. The
pregnancy-risk categories for these drugs are B and C. Patients with hypertension that is not controlled by
other medications are candidates for alpha2 therapy, since these drugs are centrally acting and have multiple
side effects. The nurse should assess these patients for the following: orthostatic hypotension; sedation;
decreased libido; impotence; sodium/water retention and dry mouth; pregnancy-risk category C. Specific
nursing considerations for beta-adrenergic drugs include monitoring for effects of vasoconstriction,
evidenced by any respiratory distress, including wheezing and shortness of breath.
6. Direct vasodilators: Key areas for the nurse to assess and monitor include the following: Since these drugs
are used primarily for emergency situations to reduce blood pressure quickly, the vital signs, ECG, and
pulse oximetry should be continuously monitored; assess the health history specifically for hypersensitivity,
coronary artery disease, rheumatic mitral-valve disease, cerebrovascular disease, renal insufficiency, and
systemic lupus erythematosus, since these conditions are contraindicated with these drugs. Additional
nursing considerations are monitoring for priapism; signs of fluid retention with repeated IV diazoxide
(Hyperstat); body-hair changes and orthohypotension with administration of minoxidil (Loniten) that
reverse when drug is stopped. Nurses should only mix nitroprusside IV administration with 5% dextrose in
water, and know that this drug is extremely light sensitive (container should be wrapped in an opaque
substance), is brown in color, and is only stable for 24 hours. This drug can be used for hypertensive
emergencies during labor and delivery.
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LEARNING OUTCOME 8
For each of the drug classes listed in Drugs at a Glance, know representative drug examples, and explain their
mechanisms of drug action, primary actions, and important adverse effects.
Concepts
1. Diuretics: The prototype drug is hydrochlorothiazide (HydroDiuril). The mechanism of action is to
decrease blood pressure by increasing the amount of urine produced and excreted. Primary use is for mild to
moderate hypertension. Adverse effects include electrolyte imbalances, especially loss of potassium.
2. Calcium channel blockers: The prototype drug is nifedipine (Procardia). The mechanism of action is to
cause vasodilation in the arteriole, which decreases blood pressure by blocking calcium channels in the
plasma membrane. Primary use is for hypertension and angina. Adverse effects include dizziness, headache,
and flushing.
3. Drugs affecting the renin-angiotensin system: Angiotensin- converting enzyme (ACE) inhibitors. The
prototype drug is enalapril (Vasotec). The mechanism of action is to decrease blood pressure by decreasing
blood volume through blocking of the angiotensin- converting enzyme (ACE). This blocks formation of
angiotensin II, causing vasodilation and decreased reabsorption of sodium by the kidneys with increased
urine excretion. The primary use is for hypertension, with some significant adverse effects being persistent
cough and hypotension. An example of angiotensin-receptor blockers (ARBs) is the prototype drug losartan
potassium (Cozaar). The mechanism of action is to decrease blood pressure by blocking angiotensin
receptors in arterial smooth muscle and adrenal glands, causing arterial dilation and increased renal sodium
excretion. The primary use is for hypertension; an adverse effect is hypotension.
4. Adrenergic antagonists: The prototype drugs are the alpha-adrenergic blocker doxazosin (Cardura) and the
beta-adrenergic blocker metoprolol (Lopressor). The mechanism of action is to decrease blood pressure by
blocking alpha and beta receptors or stimulation of alpha2 in the vasomotor center (brain stem), which
blocks effects of the sympathetic nervous system leading to vasodilation. Its primary use is to treat
hypertension, with significant adverse effects such as orthostatic hypotension, dizziness, nausea,
bradycardia, and dry mouth.
5. Direct vasodilators: The prototype drug is hydralazine (Apresoline). The mechanism of action is to
decrease blood pressure through direct relaxation of arterial smooth muscle, causing vasodilation. Its
primary use is for severe hypertension and hypertensive crisis. The adverse effects would include reflex
tachycardia and sodium and fluid retention.
Table 23.3 Diuretics for Hypertension
Table 23.4 Calcium Channel Blockers for Hypertension
Table 23.5 ACE Inhibitors and Angiotensin II Receptor Blockers for Hypertension
Table 23.6 Adrenergic Antagonists for Hypertension
Table 23.7 Direct-acting Vasodilators for Hypertension
Prototype Drug

Ch 23-6
hydrochlorothiazide (Microzide)
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
nifedipine (Adalat, Procardia, others)

enalapril (Vasotec)

doxazosin (Cardura)

hydralazine (Apresoline)
LEARNING OUTCOME 9
Use the nursing process to care for patients receiving antihypertensive drugs.
Concepts
1. Assessment process will include taking the patient’s blood pressure in each arm for baseline; assessing the
patient’s height and weight, and obtaining blood and urine samples as ordered by the physician; obtaining a
nursing history, including lifestyle, current medications, and dietary habits. Assess the patient’s and family’s
knowledge of hypertension and medication regimen.
2. Nursing diagnoses: Possible nursing diagnoses for various antihypertensive drugs: Decreased Cardiac
Output related to excessive or prolonged systemic vascular resistance; Knowledge Deficit regarding
condition, therapeutic regimen, and potential side effects of medications; Ineffective Therapeutic-Regimen
Management related to complexity of therapy and cost of medications; Risk for Sexual Dysfunction related
to side effects of medications.
3. Planning: Goals for patients receiving antihypertensive drugs include a reduction in systolic/diastolic blood
pressure and the patient’s ability to explain hypertension and needed medications and to verbalize the ability
to follow prescribed therapy.
4. Implementation: Encourage compliance with medication regimen, and provide additional education
regarding medication regimen, such as consultation with the clinical pharmacist, written and/or visual
educational material, and home-health visits to ensure patient’s ability to follow prescribed therapy.
5. Evaluation: Ideal outcome criteria for evaluation of the plan of care are a lowered blood pressure with
limited side effects, no organ damage, and no injury. Patients should be able to verbalize the importance of
taking prescribed medications to assist them in their continued management of the disease.
NURSING PROCESS FOCUS

Patients Receiving Diuretic Therapy

Patients Receiving Calcium Channel Blocker Therapy

Patients Receiving ACEI (Angiotension-Converting Enzyme Inhibitor) and ARB (Angiotension
Receptor Blocker) Therapy

Patients Receiving Adrenergic Antagonist Therapy

Patients Receiving Direct Vasodilator Therapy
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Ch 23-8
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