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Agents that Dilate Coronary Blood Vessels
Coronary artery disease (CAD) results from atherosclerosis
Clinical symptoms caused by narrowing of the vessels inadequate delivery of blood, nutrients,
and oxygenLocalized muscle injuryIncreased lactic acid
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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
Coronary and Peripheral Artery Disease
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Angina pectoris : chest painaffects ~ 9.8 million Americans/year
More prevalent in older menThe more vessels involved, the poorer the prognosis
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Angina Pectoris
Used to treat coronary artery disease
Coronary artery disease: inadequate delivery of blood, nutrients, and oxygen to the tissues
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Coronary Vasodilators
Three main objectives: ◦Minimize frequency, duration, and intensity of episodes◦Offer few side effects◦Prevent myocardial infarction—death
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Vasodilator Drug Agents
Increase blood flow to ischemic heart muscle
Decrease myocardial oxygen demand
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Therapeutic Objectives
Minimize the frequency of attacks
Improve the client’s functional capacity
Prevent or delay heart disease
.
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Therapeutic Objectives
Acetylsalicylic acid (ASA)NitratesCalcium channel blockers Beta blockersAngiotensin II receptor blockers
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Main Classes
Nitroglycerine◦Forms: sublingual, buccal, chewable, tablets, ointments, patches, spray, and intravenous
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Nitrates
Causes central and peripheral vasodilatation◦Relaxes smooth muscles
Potent dilating effect on coronary arteries
Used for prophylaxis and acute treatment of angina
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Nitroglycerine
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
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Nitroglycerin
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
Nitro: nursing considerations
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Example of long-acting nitrate◦Isosorbide dinitrate (Isordil)
Provides:◦Acute relief of angina
◦Long-term prophylaxis of angina
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Nitrates
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General Side Effects Headache
Diminish in intensity and frequency with use
Tachycardia Postural hypotension Dermatitis Tolerance
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
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Tolerance to Nitrates
Additive hypotension with use of:◦Alcohol◦Beta blockers◦Calcium channel blockers◦Phenothiazines
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Interactions
Reduces calcium ion influx:◦Reduction of myocardial oxygen consumption◦Coronary artery dilation
Example: VerapamilSide effects◦Dizziness, flushing, supraventricular arrhythmias
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Calcium Channel Blockers
Block the beta receptors◦Reduce heart rate ◦Reduce contractility◦Reduce blood pressure
Example◦Atenolol
Side effects◦Flushing, bradycardia, and bronchospasm
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Beta-adrenergic Blocking Agents
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
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Peripheral Vasodilators
Inhibits platelet clumping◦Given as a preventive agent◦Given when a person is experiencing a myocardial infarction
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Aspirin
Patients should carry IDTeach smoking/tobacco cessation, med use
Assess angina attacksTeach: nitroglycerine (NTG) most effective when taken at the beginning of an angina episode
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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
Nursing considerations
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