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Chapter 17

Chapter 17. Agents that Dilate Coronary Blood Vessels. Coronary and Peripheral Artery Disease. Coronary artery disease (CAD) results from atherosclerosis Clinical symptoms caused by narrowing of the vessels inadequate delivery of blood, nutrients, and oxygen

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Chapter 17

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  1. Chapter 17 Agents that Dilate Coronary Blood Vessels

  2. Coronary and Peripheral Artery Disease • Coronary artery disease (CAD) results from atherosclerosis • Clinical symptoms caused by • narrowing of the vessels • inadequate delivery of blood, nutrients, and oxygen • Localized muscle injury • A shift from aerobic to anaerobic metabolism • Increased lactic acid .

  3. Coronary and Peripheral Artery Disease • Pain produced (angina pectoris) • When the supply of oxygen and nutrients in the blood is insufficient to meet the demands of the heart, the muscle aches • Aggravated with stress or exercise • Drugs treat by dilating coronary blood vessels

  4. Angina Pectoris • Angina pectoris : chest pain • affects ~ 9.8 million Americans/year • More prevalent in older men • The more vessels involved, the poorer the prognosis .

  5. Coronary Vasodilators • Used to treat coronary artery disease • Coronary artery disease: inadequate delivery of blood, nutrients, and oxygen to the tissues

  6. Vasodilator Drug Agents • Three main objectives: • Minimize frequency, duration, and intensity of episodes • Offer few side effects • Prevent myocardial infarction—death .

  7. Therapeutic Objectives • Increase blood flow to ischemic heart muscle • Decrease myocardial oxygen demand

  8. Therapeutic Objectives • Minimize the frequency of attacks • Improve the client’s functional capacity • Prevent or delay heart disease .

  9. Main Classes • Acetylsalicylic acid (ASA) • Nitrates • Calcium channel blockers • Beta blockers • Angiotensin II receptor blockers .

  10. Nitrates • Nitroglycerine • Forms: sublingual, buccal, chewable, tablets, ointments, patches, spray, and intravenous .

  11. Nitroglycerine • Causes central and peripheral vasodilatation • Relaxes smooth muscles • Potent dilating effect on coronary arteries • Used for prophylaxis and acute treatment of angina .

  12. Nitroglycerin • Large first-pass effect when taken orally • Transdermal—very effective • IV form effectively used for: • Hypertension • Congestive heart failure • Ischemic pain, myocardial infarction • Pulmonary edema .

  13. Nitro: nursing considerations • Do not leave the patient when he or she is changing positions after starting a new prescription for nitro • Nitroglycerin is intended to cause rapid vasodilation -> dizziness with position change • Nitro paste: remove med from patient’s skin and wash/dry before reapplying • Always wear gloves when applying nitro topically

  14. Nitrates • Example of long-acting nitrate • Isosorbide dinitrate (Isordil) • Provides: • Acute relief of angina • Long-term prophylaxis of angina .

  15. General Side Effects • Headache • Diminish in intensity and frequency with use • Tachycardia • Postural hypotension • Dermatitis • Tolerance .

  16. Tolerance to Nitrates • Long-acting form can become ineffective • Solution • Remove patch or cream at night for 8 hours • Take the oral form for 16 hours a day .

  17. Interactions • Additive hypotension with use of: • Alcohol • Beta blockers • Calcium channel blockers • Phenothiazines .

  18. Calcium Channel Blockers • Reduces calcium ion influx: • Reduction of myocardial oxygen consumption • Coronary artery dilation • Example: Verapamil • Side effects • Dizziness, flushing, supraventricular arrhythmias .

  19. Beta-adrenergic Blocking Agents • Block the beta receptors • Reduce heart rate • Reduce contractility • Reduce blood pressure • Example • Atenolol • Side effects • Flushing, bradycardia, and bronchospasm

  20. Peripheral Vasodilators • Angiotensin II receptor blockers • Block adrenergic receptors, or • Direct action • Interfere with epinephrine action • Sympathetic nervous system is not stimulated • Result: decreased blood pressure • Side effects • Orthostatic hypotension

  21. Aspirin • Inhibits platelet clumping • Given as a preventive agent • Given when a person is experiencing a myocardial infarction

  22. Nursing Considerations • Patients should carry ID • Teach smoking/tobacco cessation, med use • Assess angina attacks • Teach: nitroglycerine (NTG) most effective when taken at the beginning of an angina episode

  23. Nursing considerations • Teach: replace sublingual NTG Q 3 months • IV NTG requires special preparation: glass, not plastic • Give beta-blocking agents before vasodilators • Monitor blood pressure routinely

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