Embed Size (px)
Citation preview
Chapter 18
Agents that Dilate Blood Vessels
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 2
Coronary Vasodilators
Used to treat coronary artery disease Coronary artery disease: inadequate
delivery of blood, nutrients, and oxygen to the tissues
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 3
Chest Pain/Angina
When the supply of oxygen and nutrients in the blood is insufficient to meet the demands of the heart, the heart muscle aches.
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 4
Vasodilator Drug Agents
Three main objectives: Minimize frequency, duration, and
intensity of episodes Offer few side effects Prevent myocardial infarction—death
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 5
Therapeutic Objectives
Increase blood flow to ischemic heart muscle
Decrease myocardial oxygen demand
(continues)
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 6
Therapeutic Objectives
Minimize the frequency of attacks Improve the client’s functional capacity Prevent or delay heart disease
(continued)
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 7
Main Classes
Acetylsalicylic acid (ASA) Nitrates Calcium channel blockers Beta blockers Angiotensin II receptor blockers
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 8
Nitrates
Nitroglycerine Forms: sublingual, buccal, chewable,
tablets, ointments, patches, spray, and intravenous
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 9
Nitroglycerine
Causes central and peripheral vasodilation
Relaxes smooth muscles Potent dilating effect on coronary arteries Used for prophylaxis and acute treatment
of angina
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 10
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
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 11
Nitrates
Example of long-acting nitrate Isosorbide dinitrate (Isordil)
Provides: Acute relief of angina Long-term prophylaxis of angina
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 12
General Side Effects
Headache Diminish in intensity and frequency with use
Tachycardia Postural hypotension Dermatitis Tolerance
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 13
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
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 14
Interactions
Additive hypotension with use of: Alcohol Beta blockers Calcium channel blockers Phenothiazines
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 15
Calcium Channel Blockers
Reduces calcium ion influx: Reduction of myocardial oxygen
consumption Coronary artery dilation
Example: verapamil Side effects
Dizziness, flushing, supraventricular arrhythmias
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 16
Beta-adrenergic Blocking Agents
Block the beta receptors Reduce heart rate Reduce contractility Reduce blood pressure
Example Atenolol
Side effects Flushing, bradycardia, and bronchospasm
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 17
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
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
18 - 18
Aspirin
Inhibits platelet clumping Given as a preventive agent Given when a person is experiencing a
myocardial infarction
