Drugs Used to Treat Angina Pectoris

Objectives

1 Define angina pectoris and identify assessment data needed to evaluate an anginal attack.

3 Describe the actions of nitrates, beta-adrenergic blockers, calcium channel blockers, and angiotensin-converting enzyme inhibitors on the myocardial tissue of the heart.

4 Identify medication therapy health teaching used for an anginal patient in the clinical setting.

Key Terms

angina pectoris () (p. 404)

ischemia () (p. 404)

chronic stable angina () (p. 404)

unstable angina () (p. 404)

variant angina () (p. 404)

Angina Pectoris

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Coronary artery disease (CAD) is the leading cause of disability, socioeconomic loss, and death in the United States, and angina pectoris is the first clinical indication of underlying coronary artery disease in many patients. Angina pectoris is the name given to a feeling of chest discomfort arising from the heart because of lack of oxygen getting to the heart cells. It is a symptom of coronary artery disease, and is also called ischemic heart disease. Ischemia develops when the supply of oxygen needed by the heart cells is inadequate. The lack of oxygen occurs when blood flow through the coronary arteries is reduced by atherosclerosis or spasm of the arteries. Atherosclerosis can develop as localized plaques or as a generalized narrowing of the coronary arteries. Patients are usually asymptomatic until there is at least 50% narrowing of the artery. Coronary artery disease caused by atherosclerosis is a progressive disease; however, progression can be slowed with diet control and with the use of cholesterol-lowering agents (see Chapter 22).

The presentation of angina pectoris is highly variable. The sensation of discomfort is often described variously as squeezing, tightness, choking, pressure, burning, or heaviness. This discomfort may radiate to the neck, lower jaw, shoulder, and arm. The usual anginal attack begins gradually, reaches its peak intensity over the next several minutes, and then gradually subsides after the person stops activity and rests. Attacks can last from 30 seconds to 30 minutes. Anginal episodes are usually precipitated by factors that require an increased oxygen supply (e.g., physical activity, such as climbing a flight of stairs or lifting). Other precipitating factors include exposure to cold temperatures, emotional stress, sexual intercourse, and eating a large meal.

Angina pectoris is classified as chronic stable, unstable, or variant angina. Chronic stable angina is precipitated by physical exertion or stress, lasts only a few minutes, and is relieved by rest or nitroglycerin. It is usually caused by fixed atherosclerotic obstruction in the coronary arteries. Unstable angina is unpredictable; it changes in ease of onset, frequency, duration, and intensity. It is probably caused by a combination of atherosclerotic narrowing, vasospasm, and thrombus formation. Variant angina occurs while the patient is at rest; it is characterized by specific electrocardiographic changes, and it is caused by vasospasm of a coronary artery reducing blood flow. The type of angina pectoris is diagnosed by a combination of history, electrocardiographic changes during an anginal attack, and exercise tolerance testing with or without thallium-201 scintigraphy.

Treatment of Angina Pectoris

The goals for the treatment of angina pectoris are to prevent myocardial infarction and death (thereby prolonging life), and to relieve anginal pain symptoms, thereby improving the quality of life. In many cases, coronary angioplasty or coronary artery bypass surgery will be considered first, because these treatments have been proven to save lives over time. The choice of therapy often depends on the patient’s clinical response to initial medical therapy.

Life Span Considerations

Anginal Attacks

The goal of the treatment of an anginal attack, which most often occurs in older adults, is the relief of pain rather than simply the reduction of pain. If pain is not relieved by nitroglycerin, then the patient should immediately contact the health care provider or be seen in the emergency department. Analgesics should not be administered in an attempt to eliminate the patient’s pain.

All patients should receive extensive patient education to help them reduce their risks related to coronary artery disease. The avoidance of activities that can precipitate attacks (e.g., strenuous exercise, exposure to cold weather, drinking caffeine-containing beverages, cigarette smoking, eating heavy meals, emotional stress) should be attempted. Risk factors (e.g., diabetes mellitus, hypertension, dyslipidemia) must also be treated. A structured exercise program designed for each patient can be successful for weight reduction among overweight patients, and it can also improve cardiovascular health. Healthy muscle tissue requires less oxygen. Medications, in combination with risk reduction and exercise, are effective in preventing ischemic attacks and myocardial infarction.

Drug Therapy for Angina Pectoris

Actions

The underlying pathophysiology of ischemic heart disease is an imbalance between the oxygen demands of the heart and the ability of coronary arteries to deliver the needed oxygen, the spasticity of the coronary arteries, platelet aggregation, and thrombus formation. The oxygen demand of the heart is determined by the heart rate, contractility, and ventricular volume. Therefore, the pharmacologic treatment of angina is aimed at decreasing oxygen demand by decreasing heart rate, myocardial contractility, and ventricular volume without inducing heart failure. Because platelet aggregation, blood flow turbulence, and blood viscosity also play certain roles—especially with unstable angina—platelet inhibitors are also prescribed to prevent anginal attacks (see Chapter 27). Because atherosclerosis causes narrowing and closure of the coronary arteries, inducing angina and myocardial infarction, the use of the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (i.e., the statins) has also become standard therapy in treating angina pectoris (see Chapter 22).

Uses

Seven groups of drugs may be used to treat angina pectoris: nitrates, beta-adrenergic blockers, angiotensin-converting enzyme (ACE) inhibitors, calcium channel blockers, statins, platelet-active agents, and fatty oxidase enzyme inhibitors. Combination therapy is beneficial for many patients. Beta blockers, calcium channel blockers, long-acting nitrates, and ranolazine can prevent anginal episodes. Risk factor management, healthy lifestyle changes, antiplatelet agents, and ACE inhibitors can prevent disease progression and myocardial infarction or death.

Drug therapy for patients with angina must be individualized. Most patients will be given prescriptions for medication (e.g., nitroglycerin in the form of sublingual tablets or translingual spray) to treat acute attacks and prescriptions for therapy to prevent further ischemia and myocardial infarction (and possible death). Therapy to prevent myocardial infarction consists of statins to lower low-density lipoprotein (LDL) cholesterol levels and to reduce inflammation; platelet inhibitors to prevent platelet aggregation and thrombus formation; and ACE inhibitors to help dilate coronary blood vessels and to reduce the potential for thrombus formation.

The most effective agents for relieving ischemia and angina are beta blockers, calcium channel blockers, and nitrates. The drug ranolazine, which is a fatty oxidase enzyme inhibitor, modifies metabolism in the myocardial cells to reduce the oxygen demand of the contracting heart muscles, thereby reducing symptoms of angina.

Deciding which medicine to use depends on other conditions that the patient may have and the expected adverse effects of therapy. Aspirin, clopidogrel, or ticlopidine (see Chapter 27), which are platelet-active agents, may also be considered to slow platelet aggregation. Many patients will have revascularization procedures (e.g., stent placement, coronary artery bypass grafting) to restore blood flow and to reduce symptomatology. Even after revascularization, patients will still require antianginal drug therapy.

Nursing Implications for Anginal Therapy

Assessment

History of Anginal Attacks.

Ask the patient specific questions to identify the onset, duration, and intensity of the pain. Ask the patient to describe the chest sensation and the pattern of occurrence (e.g., under the sternum; in the jaw, neck, and shoulder; radiation down the left arm, the right arm, or both; into the wrist, hand, and fingers). What activities precipitate an attack? Does the pain occur with or without exertion? Is the pain relieved by rest? Does the chest pain occur shortly after eating? Does the individual experience fatigue, shortness of breath, indigestion, or nausea in relation to the anginal attack? Work with the patient to plan interventions that will minimize the factors that trigger attacks. Mutually establish goals with the patient to alter risk factors that are modifiable.

For information about medication administration, see the individual drug monographs.

Patient Education and Health Promotion

Medications

• Teach the patient about the signs and symptoms of hypotension, which may occur when nitrates are taken. Weakness, dizziness, or faintness can usually be relieved by increasing muscular activity (i.e., alternating flexing and relaxing the muscles in the legs) or by sitting or lying down. Resting for 10 to 15 minutes after taking medication may also assist the patient with the management of hypotension. Because lightheadedness or fainting is a possibility when taking nitroglycerin, safety measures to prevent injury from transient orthostatic hypotension must be stressed.

• Explain that a headache may occur with the use of nitroglycerin but that it should subside within 20 to 30 minutes.

• Teach specific administration techniques to the patient for the type of medication prescribed (e.g., sublingual or transmucosal tablets, translingual spray, topical ointment, transdermal disks). Refer to Figure 8-2 and Figure 8-3 for further description of percutaneous administration of nitroglycerin.

Lifestyle Modifications

Lifestyle modifications are essential for many individuals with angina. Teach the patient about appropriate behavioral changes, such as stress management (e.g., relaxation techniques, meditation, three-part breathing).

• The patient must resume ADLs within the boundaries set by the health care provider. Encourage activities such as regular moderate exercise, meal preparation, the resumption of usual sexual activity, and social interactions.

• Individuals who are unable to attain the degree of activity hoped for through drug therapy may become frustrated. Allow for the verbalization of feelings, and then implement actions that are appropriate to the circumstances.

• Participation in regular exercise is essential. Follow the guidelines of the American Heart Association regarding an exercise program. Increase the patient’s exercise demands gradually, and monitor the effects on his or her cardiovascular system. Changes in the level of exercise may require participation in a supervised program (e.g., cardiac rehabilitation). Tell the patient to avoid overexertion. Anginal pain may occur with exercise, and taking nitroglycerin before exercise or before performing certain activities may be recommended. Instruct the patient to always stop exercising or performing any activity when chest pain is present.

• Discuss the need for smoking cessation, and make referrals to available self-help programs in the area. Smoking causes vasoconstriction; encourage a drastic reduction in smoking and preferably complete elimination of smoking. Encourage the patient to set a date to stop smoking.

• Dietary modifications aimed at decreasing the cholesterol level and a reducing program to maintain the ideal weight are usually prescribed by the physician. Depending on coexisting conditions, other dietary modifications (e.g., a low-sodium diet) may be suggested. Discourage the use of caffeine-containing products, because they may precipitate an anginal attack when they are taken in excess.

• If hypertension accompanies the angina, stress the importance of following prescribed dietary, and medicinal regimens to control the disease.

• Instruct the patient not to ingest alcohol while receiving nitroglycerin therapy. Alcohol causes vasodilation, which potentially results in postural hypotension.

• Teach the patient about the proper storage of medication (especially sublingual nitroglycerin) in a dark, airtight container. Show the patient the medication’s expiration date, and stress the importance of having the prescription refilled before the expiration date.

• Always report poor pain control to the health care provider.

Fostering Health Maintenance

• Throughout the course of treatment, discuss medication information and how it will benefit the patient.

• Drug therapy is essential to maintain the adequate oxygenation of the myocardial cells and body tissues. Although medications can control the anginal attacks, lifestyle changes to deal with the management of precipitating factors must also occur.

• Provide the patient and his or her significant others with the important information contained in the specific drug monographs for the drugs prescribed. Additional health teaching and nursing interventions for common and serious adverse effects are described in the drug monographs later in this chapter.

• Seek cooperation and understanding with regard to the following points so that medication adherence is increased: the name of the medication; its dosage, route, and times of administration; and its common and serious adverse effects.

Written Record.

Enlist the patient’s help with developing and maintaining a written record of monitoring parameters (e.g., blood pressure, pulse, degree of pain relief, exercise tolerance, adverse effects experienced)(see Patient Self-Assessment Form for Cardiovascular Agents on the Evolve website). Complete the Premedication Data column for use as a baseline to track the patient’s response to drug therapy. Ensure that the patient understands how to use the form, and instruct the patient to bring the completed form to follow-up visits. During follow-up visits, focus on issues that will foster the patient’s adherence with the therapeutic interventions prescribed.