Chapter 13
Drugs Affecting Adrenergic Function
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Question
• The sympathetic nervous system produces what type of
response?
– A. Adrenergic
– B. Antiadrenergic
– C. Cholinergic
– D. Anticholinergic
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Answer
• The sympathetic nervous system produces what type of
response?
– A. Adrenergic
– The sympathetic nervous system produces an
adrenergic response, and the parasympathetic
nervous system produces a cholinergic response.
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Chapter Summary
• The nervous system is divided into two main branches,
the central nervous system (CNS) and the peripheral
nervous system (PNS).
• The efferent division has neurons that carry signals away
from the brain and spinal cord to the periphery.
• The afferent division contains neurons that carry
impulses from the periphery to the CNS.
• The autonomic nervous system (ANS) is in turn
subdivided into the sympathetic nervous system (SNS)
and the parasympathetic nervous system (PSNS).
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Function of the Autonomic Nervous
System
• The ANS has been identified as an involuntary system
responsible for the control of smooth muscle.
• The actual connection between neurons and effector organs or
tissues relies on neurotransmitters and synaptic transmission.
• The neurotransmitters in the ANS include acetylcholine (ACh),
norepinephrine (NE), and epinephrine (Epi).
• Synaptic transmission initially involves the synthesis of
neurotransmitters in the nerve terminal.
• In the SNS, preganglionic transmission is mediated by ACh,
whereas postganglionic transmission is mediated by NE.
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SNS and PSNS Effects on the Body
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Adrenergic Receptors
• In the SNS, there are several types of adrenergic receptors,
including alpha-adrenergic and beta-adrenergic receptors.
• Another type of receptor, the dopaminergic receptor, is related
to adrenergic receptors in that dopamine is the precursor to
NE.
• Alpha and beta receptors are located throughtout the body.
• Alpha-1 and beta-1 receptors respond to epinephrine, NE, and
dopamine.
• Alpha-2 receptors respond to epinephrine and NE.
• Beta-2 receptors respond only to epinephrine.
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Pathophysiology
• The therapeutic uses of sympathetic drugs are related to
providing extra-adrenergic stimulation or blockade of
normal ANS functioning.
• One of the most frequent indications for adrenergic
agonist drugs is shock.
• Shock is the result of inadequate tissue perfusion,
leaving the cells without the oxygen and nutrients they
need to function normally and survive.
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Adrenergic Agonists
• Adrenergic agonists are drugs that mimic the action of the
SNS.
• They exert their effects by direct or indirect stimulation of
adrenergic receptors.
• These drugs are generally divided into two groups:
catecholamines and noncatecholamines.
• Adrenergic agonists are also classified according to their
selectivity.
• Nonselective adrenergic agonists stimulate both alpha and beta
receptors.
• Prototype drug nonselective adrenergic agonist: epinephrine.
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Epinephrine: Core Drug Knowledge
• Pharmacotherapeutics
– Wide variety of indications: asthma, shock, etc.
• Pharmacokinetics
– Administered: parenterally, topically, or by inhalation.
Metabolism: liver. Absorption: into the tissues. Excreted:
kidneys. Duration: 1-4 hours.
• Pharmacodynamics
– It stimulates all adrenergic receptors and causes adverse
effects in the cardiovascular system and CNS.
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Epinephrine: Core Drug Knowledge
• Contraindications and precautions
– Absolute contraindications to epinephrine include
hypersensitivity, sulfite sensitivity, closed-angle glaucoma,
and its use during labor.
• Adverse effects
– Severe adverse effects include hypertensive crisis, angina,
cerebral hemorrhage, and cardiac arrhythmias.
• Drug interactions
– Tricyclic antidepressants, oxytocics, halogenated
anesthetics, and beta blockers
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Epinephrine: Core Patient Variables
• Health status
– Document preadministration vital signs. Review health
history.
• Life span and gender
– Pregnancy risk category C
• Lifestyle, diet, and habits
– Document the patient’s occupation and daily activities.
• Environment
– IV administration only by trained personnel
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Epinephrine: Nursing Diagnoses and
Outcomes
• Imbalanced Nutrition: Less Than Body Requirements related to druginduced anorexia or nausea
–
Desired outcome: the patient will maintain adequate nutrition.
• Disturbed Sleep Pattern, Insomnia, related to CNS excitation
–
Desired outcome: the patient will learn about and practice sleep
hygiene.
• Disturbed Sensory Perception related to impaired vision
–
Desired outcome: the patient will notify the provider if vision
changes occur.
• Ineffective Tissue Perfusion (Cardiopulmonary) related to cardiovascular
effects of epinephrine
–
Desired outcome: the patient will notify the provider if tachycardia,
chest pain, or palpitations occur.
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Epinephrine: Planning & Interventions
• Maximizing therapeutic effects
– Requires close monitoring of vital signs and careful
monitoring for adverse effects.
– Take as prescribed.
• Minimizing adverse effects
– When treating anaphylactic shock, monitor blood pressure.
– Assisting the patient with menu planning may help to
promote appetite and counteract the anorectic influence of
epinephrine.
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Epinephrine: Teaching, Assessment &
Evaluations
• Patient and family education
– Acute illness: Teaching should be brief, simple, and
supportive.
– Explain how to administer drug properly.
• Ongoing assessment and evaluation
– Assess the patient for resolution of the presenting
problem.
– Important to remember that epinephrine is a
nonselective adrenergic agonist.
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Question
• Which of the following receptors is (are) stimulated by
epinephrine?
– A. Alpha 1
– B. Alpha 2
– C. Beta 1
– D. Beta 2
– E. All of the above
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Answer
• Which of the following receptors is (are) stimulated by
epinephrine?
– E. All of the above
– Epinephrine is a nonselective adrenergic agonist. This
drug stimulates alpha-1, alpha-2, beta-1, and beta-2
receptors. The only adrenergic receptor subtype it
does not stimulate is the dopamine receptor.
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Alpha-1 Adrenergic Agonists
• The alpha-1 adrenergic agonists are drugs that stimulate
the alpha-1 receptor directly.
• Prototype drug: phenylephrine (Allerest)
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Phenylephrine: Core Drug Knowledge
• Pharmacotherapeutics
– Used parenterally for vascular failure in shock.
– Used topically for relief of nasal mucosal congestion.
• Pharmacokinetics
– Administered: parenterally or topically. Metabolism: liver.
Excreted: urine. Onset: 15 to 20 minutes. Duration: 1-2
hours.
• Pharmacodynamics
– Is structurally similar to epinephrine and is a powerful
alpha-1 adrenergic agonist.
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Phenylephrine: Core Drug Knowledge
• Contraindications and precautions
– Hypersensitivity, sulfite sensitivity, severe hypertension,
ventricular tachycardia, and closed-angle glaucoma
• Adverse effects
– Headache, restlessness, excitability, and reflex
bradycardia
• Drug interactions
– Monoamine oxidase inhibitors (MAOIs), tricyclic
antidepressants, and oxytocics
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Phenylephrine: Core Patient Variables
• Health status
– Assess medical history and obtain baseline assessment
• Life span and gender
– Used in pregnancy only if absolutely necessary
• Lifestyle, diet, and habits
– Document the patient’s occupation and activities of daily
living
• Environment
– Closely monitor during administration in acute care setting
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Phenylephrine : Nursing Diagnoses and
Outcomes
• Impaired Gas Exchange related to bronchoconstriction
– Desired outcome: gas exchange will remain unimpaired.
• Imbalanced Nutrition: Less Than Body Requirements related to
anorexia or nausea
– Desired outcome: the patient will take sufficient
nourishment.
• Disturbed Sleep Pattern, Insomnia, related to CNS excitation
secondary to phenylephrine use
– Desired outcome: the patient will maintain normal sleep
patterns.
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Phenylephrine: Planning & Interventions
• Maximizing therapeutic effects
– Corrected any blood losses prior to administration.
– To produce optimal mydriasis, instill the ophthalmic form
into the conjunctival cul-de-sac.
• Minimizing adverse effects
– IV administration is through a large vein.
– Avoid driving at night because blurred vision can be
hazardous.
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Phenylephrine : Teaching, Assessment &
Evaluations
• Patient and family education
– Stress the hazards associated with driving and
operating heavy machinery.
– Teach the patient about drug interactions.
• Ongoing assessment and evaluation
– Completing a detailed and thorough history and
physical examination is essential for any patient
anticipating long-term adrenergic drug therapy.
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Alpha-2 & Beta-Adrenergic Agonists
• Alpha-2 adrenergic agonists
– Stimulation of alpha-2 receptors in the CNS decreases
sympathetic outflow by inhibiting the release of
norepinephrine.
• Beta-adrenergic agonists
– Beta-adrenergic agonists also mimic the action of the SNS.
– Beta-adrenergic agonists are also labeled according to
their selectivity.
– Prototype: dopamine (Intropin).
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Dopamine: Core Drug Knowledge
• Pharmacotherapeutics
– Used to correct the hemodynamic imbalances present in
shock.
• Pharmacokinetics
– Distribution: throughout the tissues. Metabolism: kidney,
liver, and plasma. Excreted: kidneys. Onset: 5 minutes.
Duration: 10 minutes.
• Pharmacodynamics
– Stimulates alpha-1 and beta-1 receptors: increased
cardiac output
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Dopamine: Core Drug Knowledge
• Contraindications and precautions
– Pheochromocytoma, uncorrected tachyarrhythmias,
and ventricular fibrillation
• Adverse effects
– Ectopic beats, nausea and vomiting, tachycardia,
angina, palpitation, dyspnea, headache, hypotension,
and vasoconstriction
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Dopamine: Drug Interactions
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Dopamine: Core Patient Variables
• Health status
– Assess medical history (chronic illness & allergies)
• Life span and gender
– Pregnancy category C drug
• Environment
– Administered only in acute care settings
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Dopamine : Nursing Diagnoses and
Outcomes
• Risk for Ineffective Tissue Perfusion to Vital Organs
related to drug effect
– Desired outcome: the patient will maintain
sufficient perfusion of vital organs to prevent serious
damage.
• Risk for Injury related to adverse effects of drug therapy
– Desired outcome: adverse effects of drug therapy
will not occur or will be minimized to prevent injury.
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Dopamine: Planning & Interventions
• Maximizing therapeutic effects
– Administer using an infusion pump to regulate flow.
– Titrate dose to desired effect.
• Minimizing adverse effects
– Follow the manufacturer’s instructions for dilution.
– Monitor IV site.
– Assess for disproportionate rise in diastolic blood
pressure.
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Dopamine: Teaching, Assessment &
Evaluations
• Patient and family education
– If administered during a crisis, limited teaching
occurs at that time.
– Reassure the patient and family that the patient will
be monitored closely during administration of the
drug.
• Ongoing assessment and evaluation
– Treatment is effective if blood pressure stabilizes,
urinary output returns to normal, and cardiac output
returns to normal.
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Question
• Dopamine is administered by which route?
– A. Oral
– B. IM
– C. IV
– D. ET
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Answer
• Dopamine is administered by which route?
– C. IV
– Dopamine is given only via the IV route.
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Dopaminergic Agonists
• There are five types of dopamine receptors; only
dopamine-1 (DA1) and dopamine-2 (DA2) receptors
mediate responses in the adrenergic nervous system.
• Stimulation of DA1 and DA2 receptors results in
peripheral vasodilation.
• Stimulating both receptors may have either
complementary or opposing effects.
• Prototype drug: fenoldopam (Corlopam)
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Fenoldopam : Core Drug Knowledge
• Pharmacotherapeutics
– Short-term management of severe hypertension.
• Pharmacokinetics
– Administered: parenterally. Metabolism: by conjugation.
Excreted: urine and feces. Steady state: 20 minutes.
• Pharmacodynamics
– It does not bind with DA2, alpha, or beta receptors. It
provides rapid vasodilation to the coronary, renal,
mesenteric, and peripheral arteries.
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Fenoldopam : Core Drug Knowledge
• Contraindications and precautions
– Hypersensitivity to sulfites
• Adverse effects
– Symptomatic hypotension, tachycardia, abdominal or
back pain, GI effects, sweating, and CNS effects,
such as insomnia, dizziness, nervousness, or anxiety
• Drug interactions
– Beta blockers and diuretics
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Fenoldopam : Core Patient Variables
• Health status
– Medical history and pre-administration physical
assessment
• Life span and gender
– Pregnancy category B drug
• Environment
– Administered only in the acute care hospital setting
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Fenoldopam : Nursing Diagnoses and
Outcomes
• Risk for Ineffective Tissue Perfusion related to
hypotension, tachycardia, or increased intraocular
pressure
– Desired outcome: the patient will maintain
adequate tissue perfusion throughout therapy.
• Risk for Injury related to hypokalemia
– Desired outcome: the patient will maintain a serum
potassium level within normal limits throughout
therapy.
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Fenoldopam : Planning & Interventions
• Maximizing therapeutic effects
– Dilute with 0.9% sodium chloride or 5% dextrose.
– The drug is administered using an infusion pump.
– Titrate dose to effect.
• Minimizing adverse effects
– Visually inspect the drug ampule.
– Start at low doses and titrate up to avoid reflex
tachycardia.
– Monitor vital signs during administration.
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Fenoldopam : Teaching, Assessment &
Evaluations
• Patient and family education
– Explain to the patient and family the rationale for the
use.
– Reassure the patient that close monitoring will be
maintained throughout drug therapy.
• Ongoing assessment and evaluation
– Monitor vital signs throughout infusion.
– Evaluate the efficacy by monitoring blood pressure.
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Alpha-Adrenergic Antagonists
• Alpha-adrenergic antagonists block the stimulation of
alpha receptors.
• Alpha-1a receptors mediate human prostatic smooth
muscle contraction.
• Alpha-1b and alpha-1d receptors are involved in vascular
smooth muscle contraction.
• Prototype drug: prazosin (Minipress).
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Prazosin: Core Drug Knowledge
• Pharmacotherapeutics
– Used to treat congestive heart failure, Raynaud
vasospasm, and prostatic outflow obstruction.
• Pharmacokinetics
– Administered: oral. Metabolism: liver. Excreted: bile,
feces, and urine. Onset: 1 hour. Duration: 10 hours.
• Pharmacodynamics
– Blocks postsynaptic alpha-1 adrenergic receptors:
lowers supine and standing blood pressure.
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Prazosin: Core Drug Knowledge
• Contraindications and precautions
– Hypersensitivity; use caution with angina because
hypotension may worsen the condition
• Adverse effects
– Light-headedness, dizziness, headache, drowsiness,
weakness, lethargy, nausea, and palpitations
• Drug interactions
– Other antihypertensive medications
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Prazosin: Core Patient Variables
• Health status
– Past medical history and physical assessment
• Life span and gender
– Pregnancy category C
• Lifestyle, diet, and habits
– Document the occupation and daily activities
• Environment
– Assess environment where drug will be given
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Prazosin: Nursing Diagnoses and
Outcomes
• Ineffective Tissue Perfusion related to prazosin-induced
hypotension
– Desired outcome: the patient will maintain adequate
tissue perfusion.
• Imbalanced Nutrition: Less Than Body Requirements related to
nausea secondary to prazosin use
– Desired outcome: the patient will receive adequate
nourishment by practicing appropriate dietary
management.
• Risk for Injury related to orthostatic hypotension
– Desired outcome: the patient will remain free of injury.
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Prazosin: Planning & Interventions
• Maximizing therapeutic effects
– Take as prescribed.
– Refraining from OTC medication usage.
• Minimizing adverse effects
– Take the first dose just before bedtime.
– Monitor weight and check for edema.
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Prazosin: Teaching, Assessment &
Evaluations
• Patient and family education
– Take drug as prescribed.
– Adverse effects, including symptoms, to report to
doctor.
• Ongoing assessment and evaluation
– Monitor blood pressure, heart and lung sounds, and
edema.
– Identify potential drug interactions.
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Beta-Adrenergic Antagonists
• Grouped according to their specificity of action at the
beta-1 and beta-2 receptors.
• Stimulation of beta-1 only (tachycardia, increased
lipolysis, inotropy).
• Stimulation of both beta-1 and beta-2 receptors
(vasodilation, decreased peripheral resistance,
bronchodilation).
• Prototype drug: metoprolol (Lopressor, Toprol XL).
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Metoprolol: Core Drug Knowledge
• Pharmacotherapeutics
– Treatment of hypertension, angina, and controlled
congestive heart failure.
• Pharmacokinetics
– Administered: parenterally and orally. Metabolism: liver.
Excreted: urine and breast milk. Onset & duration: varies
with route of administration.
• Pharmacodynamics
– Decreased cardiac output and blood pressure.
– Slowing of atrioventricular conduction and suppression of
automaticity.
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Metoprolol: Core Drug Knowledge
• Contraindications and precautions
– Severe bradycardia, cardiogenic shock, airway diseases,
Raynaud syndrome, and use of antidepressant drugs
• Adverse effects
– Cognitive dysfunction, hypoglycemia, diarrhea, and severe
hypertension
• Drug interactions
– Several drug interactions
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Metoprolol: Core Patient Variables
• Health status
– Past medical and physical assessment
• Life span and gender
– Pregnancy category C
• Lifestyle, diet, and habits
– Document occupation and daily activities
• Environment
– Assess environment where drug will be given
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Metoprolol: Nursing Diagnoses and
Outcomes
• Risk for Ineffective Tissue Perfusion related to hypotension,
bradycardia, or decreased cardiac output
– Desired outcome: the patient will maintain adequate
tissue perfusion throughout therapy.
• Risk for Injury related to dizziness secondary to beta blockade
– Desired outcome: the patient will not sustain injury.
• Disturbed Sleep Pattern, Insomnia and Drowsiness, secondary
to beta blockade
– Desired outcome: the patient will sleep normally and
awaken rested.
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Metoprolol: Nursing Diagnoses and
Outcomes (cont.)
• Activity Intolerance related to lethargy and weakness
secondary to beta blockade
– Desired outcome: the patient will maintain a satisfactory
activity level.
• Risk for Fluid Volume excess related to decreased cardiac
output
– Desired outcome: the patient with chronic heart failure
will not develop worsening of symptoms while on
metoprolol.
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Metoprolol: Planning & Interventions
• Maximizing therapeutic effects
– Take medication as prescribed.
– Do not abruptly stop medication.
• Minimizing adverse effects
– Prior to dose, check the apical and peripheral
pulses.
– Monitor blood pressure, pulmonary wedge
pressure, and cardiac rhythm and conduction.
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Metoprolol: Teaching, Assessment &
Evaluations
• Patient and family education
– Do not abruptly stop medication.
– Adverse effects, including symptoms, to report to doctor.
• Ongoing assessment and evaluation
– When evaluating the success of nursing management,
anticipate the absence of signs and symptoms for the
condition being treated.
– Monitor cardiovascular system: BP, heart rate, edema.
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