Transcript Chapter 16 Cholinesterase Inhibitors

Chapter 46
Vasodilators
Copyright © 2013, 2010 by Saunders, an imprint of Elsevier Inc.
Vasodilation
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Can be produced with a variety of drugs
Some act primarily on veins or arterioles, and
some act on both types of vessels
Wide variety of therapeutic applications
Copyright © 2013, 2010 by Saunders, an imprint of Elsevier Inc.
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Basic Concepts in
Vasodilator Pharmacology
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Selectivity of vasodilatory effects
Selective dilation of arterioles
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Selective dilation of veins
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Hydralazine
Nitroglycerin
Dilate arterioles and veins
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Prazosin
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Hemodynamic Effects
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Drugs that dilate resistance vessels
(arterioles) cause a decrease in cardiac
afterload
Drugs that dilate capacitance vessels (veins)
reduce the force with which blood is returned
to the heart, thus reducing preload
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Overview of Therapeutic Uses
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Principal indications
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Essential hypertension
Hypertensive crisis
Angina pectoris
Heart failure
 Myocardial infarction
 Pheochromocytoma
 Peripheral vascular disease
 Pulmonary arterial hypertension
 Production of controlled hypotension during
surgery
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Vasodilators
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Adverse effects related to vasodilation
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Postural hypotension
Reflex tachycardia
Expansion of blood volume
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Hydralazine (Apresoline)
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Selective dilation of arterioles
Mechanism is unknown
Postural hypotension is minimal
Therapeutic uses
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Essential hypertension
Hypertensive crisis
Heart failure
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Hydralazine (Apresoline)
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Adverse effects
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Reflex tachycardia
Increased blood volume
Systemic lupus erythematosus–like syndrome
Headache, dizziness, weakness, and fatigue
Drug interactions
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Other antihypertensive agents
Avoid excessive hypotension
Combined with beta blocker to protect against reflex
tachycardia and diuretics to prevent sodium and water
retention and expansion of blood volume
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Minoxidil (Loniten)
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Selective dilation of arterioles
More intense dilation than hydralazine, but causes
more severe adverse reactions
Used for severe hypertension that is unresponsive to
safer drugs
Adverse effects
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Reflex tachycardia
Sodium and water retention
Hypertrichosis
Pericardial effusion
Other
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Sodium Nitroprusside (Nitropress)
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Fastest-acting antihypertensive agent
Causes venous and arteriolar dilation
Administration: IV infusion
Onset: immediate (BP returns to pretreatment
level in minutes when stopped)
Used for hypertensive emergencies
Adverse effects
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Excessive hypotension
Cyanide poisoning
Thiocyanate toxicity
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Fig. 46–1. Structure and metabolism of sodium nitroprusside.
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Other Vasodilators
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Angiotensin-converting enzyme (ACE) inhibitors
Angiotensin II receptor antagonists
Direct renin inhibitors
Organic nitrates
Calcium channel blockers
Sympatholytics
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Alpha-adrenergic blocking agents
Ganglionic blocking agents
Adrenergic neuron blocking agents
Centrally acting agents
Nesiritide
Drugs for pulmonary arterial hypertension
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