Ppt chapter 31-1

Adrenergic Blocking Antagonists
Chapter 31
Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins

Adrenergic Blocking Agents
• Definition
– Called sympatholytic drugs because they lyse, or
block, the effects of the SNS
• Therapeutic and Adverse Effects
– Related to their ability to react with specific
adrenergic receptor sites without activating them
• Action
– Prevent norepinephrine from activating the receptor

Site of Action of Adrenergic Blockers

Alpha- and Beta-Adrenergic Blocking
Agents and Their Indications
• Carvedilol (Coreg): Hypertension, congestive heart
failure (adult)
• Guanadrel (Hylorel): Hypertension in adults not
responding to thiazide diuretics
• Guanethidine (Ismelin): Hypertension and renal
hypertension
• Labetalol (Normodyne, Trandate): Hypertension,
pheochromocytoma, clonidine withdrawal

Agents and Their Indications (cont.)
• Phentolamine (Regitine)
– Diagnosis of pheochromocytoma
– Management of severe hypertension during
pheochromocytoma surgery
– Prevention of cell death with IV infiltration of
norepinephrine or dopamine

Agents
• Actions
– Competitively block the effects of norepinephrine at
the alpha and beta receptors throughout the SNS
– Prevents the signs and symptoms associated with
sympathetic stress reaction and results in lower
blood pressure, slower pulse, and increased renal
perfusion with decreased renin levels
• Indications
– Essential hypertension

Agents (cont.)
• Pharmacokinetics
– Well absorbed and distributed throughout the body
– Metabolized in the liver and excreted in feces and
urine
• Contraindications
– Bradycardia or heart block
– Shock or CHF

Agents (cont.)
• Caution
– Bronchospasm
• Adverse Reactions
– Dizziness, insomnia, fatigue, nausea, vomiting,
arrhythmias, hypotension, CHF, pulmonary edema,
bronchospasm
• Drug-to-Drug Interaction
– Enflurane, halothane or isoflurance anesthetics
– Diabetic agents
– Calcium channel blockers

Prototype Alpha- and Beta-Adrenergic
Blocking Agents

Nursing Considerations for Alpha- and
Beta-Adrenergic Blocking Agents
• Assessment: History and Physical Exam
• Nursing Diagnosis
• Implementation
• Evaluation

Question
What is an indication for use non-selective adrenergic
blocking agents?
A. Essential hypertension
B. Malignant hypertension
C. Secondary hypertension
D. Malignant hyperthermia

Answer
A. Essential hypertension
Rationale: The alpha- and beta-adrenergic blocking agents
block all of the receptor sites within the SNS, which
results in lower blood pressure, slower pulse, and
increased renal perfusion with decreased renin levels.
These drugs are indicated for the treatment of essential
hypertension.

Alpha-Adrenergic Blocking Agent
• Actions
– Blocks postsynaptic alpha1 receptors, decreasing
sympathetic tome in the vasculature and causing
vasodilatation
– Absorbed after injection and is excreted in the urine

Alpha-Adrenergic Blocking Agent (cont.)
– Allergy
– CAD or MI
• Caution
– Pregnancy and lactation
– Hypotension, orthostatic hypotension, angina, MI,
CVA
– Arrhythmia, weakness, and dizziness

Alpha-Adrenergic Blocking Agent (cont.)
– Ephedrine and epinephrine
– Alcohol

Prototype Alpha-Adrenergic Blocking
Agent

Nursing Considerations for
Alpha-Adrenergic Blocking Agent
• Implementation
• Evaluation

Alpha1-Selective Adrenergic Blocking
Agents
• Doxazosin (Cardura): Used to treat hypertension; also
effective in the treatment of benign prostatic hypertrophy
• Prazosin (Minipress): Used to treat hypertension, alone
or in combination with other drugs
• Terazosin (Hytrin): Used to treat hypertension as well as
BPH
• Tamsulosin (Flomax) and Alfuzosin (Uroxatral): Used
only in the treatment of BPH

Agents (cont.)
• Actions
– Block the postsynaptic alpha 1- receptor sites
– This causes a decrease in vascular tone and
vasodilatation
• Indications
– BPH and hypertension
– Well absorbed, undergo extensive hepatic
metabolism, excreted in the urine

Agents (cont.)
– Allergy, lactation
• Caution
– CHF or renal failure
– Dizziness, weakness, fatigue
– Nausea, vomiting, abdominal pain, diarrhea
– Arrhythmias, hypotension, edema, CHF, and angina

Agents (cont.)
– Vasodilators or antihypertensive drugs

Prototype Alpha1-Selective Adrenergic
Blocking Agents

Prototype Alpha1-Selective Adrenergic
Blocking Agents (Continued)

Nursing Considerations for Alpha1-
Selective Adrenergic Blocking Agents
• Implementation
• Evaluation

Question
Alpha1- selective adrenergic blocking agents are to be used
with caution in what population of patients?
A. Those with hepatic disease
B. Those with hypotension
C. Those with congestive heart failure
D. Those with respiratory distress

Answer
C. Those with congestive heart failure
Rationale: Alpha1-selective adrenergic blocking agents are
used with caution in patients who have CHF or renal
failure.

• Actions
– Competitive blocking of the beta-receptors in the SNS
– Blocking of beta receptors in the heart and in the
juxtaglomerular apparatus of the nephron
• Indications
– Treating cardiovascular problems
• Hypertension
• Angina
• Migraine headaches
– Preventing reinfarction after MI

Beta-Adrenergic Blocking Agents (cont.)
– Absorbed from GI tract and undergo hepatic metabolism
– Allergy
– Bradycardia, heart block, shock, or CHF
– COPD, asthma
• Caution
– Diabetes, hepatic dysfunction

– Fatigue, dizziness, depression, sleep disturbances
– Bradycardia, heart block, hypotension
– Bronchospasm
– Nausea, vomiting, diarrhea
– Decrease libido

– Clonidine
– NSAIDs
– Insulin or anti-diabetic medications

Prototype Beta-Adrenergic Blocking
Agents

Prototype Beta-Adrenergic Blocking
Agents (Continued)

Nursing Considerations for
• Implementation
• Evaluation

Beta1-Selective Adrenergic Blocking
Agents
• Advantage
– Do not usually block beta2-receptor sites, including
the sympathetic bronchodilation
• Preferred for patients who smoke or have asthma,
obstructive pulmonary disease, or seasonal or
allergic rhinitis
• Uses
– Hypertension, angina, some cardiac arrhythmias

Agents (cont.)
• Actions
– Selectively block beta 1 receptors in the SNS
– Absorbed from GI tract
– Metabolized in liver and excreted in urine
– Allergy
– Sinus bradycardia, heart block, cardiogenic shock, CHF, and
hypotension
• Caution
– COPD, diabetes, thyroid disease

Agents (cont.)
– Fatigue, dizziness, sleep disturbances
– Bradycardia, heart block, CHF, hypotension
– Symptoms in respiratory tract range from rhinitis to
bronchospasm
– Nausea, vomiting, diarrhea
– Decreased libido and impotence
– NSAIDs
– IV lidocaine

Prototype Beta1-Selective Adrenergic
Blocking Agents

Prototype Beta1-Selective Adrenergic
Blocking Agents (Continued)

Nursing Considerations for Beta1-Selective
Adrenergic Blocking Agents
• Implementation
• Evaluation

Use of Adrenergic Blocking Agents Across
the Lifespan

Question
You are caring for a child who has been diagnosed with a
heart problem. Propanolol has been ordered for this
patient. What would be considered in calculating a child’s
dose?
A. Child’s body weight and age
B. Child’s body mass
C. Child’s age in months and height
D. Child’s age and body mass index

Answer
A. Child’s body weight and age
Rationale: Children are at greater risk for complications
associated with the use of adrenergic blocking agents,
including bradycardia, difficulty breathing, and changes in
glucose metabolism. The safety and efficacy for use of
these drugs has not been established for children
younger than 18 years of age. If one of these drugs is
used, the dosage for these agents needs to be calculated
from the child’s body weight and age.

Ppt chapter 31-1

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Ppt chapter 31-1