NUR 326 Lecture Notes - Lecture 3: Cardiac Arrhythmia, Cardiogenic Shock, Decongestant
18 May 2020
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Chapter 18: Adrenergic Agonists and Adrenergic Blockers
Adrenergic drugs stimulate the sympathetic nervous system and are called adrenergics, adrenergic agonists, or sympathomimetics, because they mimic the
sympathetic neurotransmitters norepinephrine and epinephrine
Vasoactive Adrenergic
• Primarily cardiovascular side effects
• Watch for tachycardia and palpitations
Used to support failing heart or treatment of shock
• Failing heart: shortness of breath, fluid overload, tachycardia
• Shock: hypotension, high heart rate (but heart does not fill
properly)
Dobutamine (Dobutrex) – beta1 adrenergic which
increases cardiac output and blood pressure (used for
heart failure)
• Treats cardiac decompensation by enhancing myocardial
contractility→ may cause tachycardia and
dysrhythmias
Dopamine (Inotropin) –beta1, alpha-adrenergic which is
indicated for shock or hypotensive
• Increases CO → phentoamine (a-blocker) if extravastion
Epinephrine (Adrenalin)
Norepinephrine (Levophed)
Neo-Synepherine (Phenylephrine)
Epinephrine acts directly on alpha and beta receptors, bronchodilation,
increased heart rate, CO.
Indications: to treat allergic reaction, anaphylaxis (promotes
bronchodilation), cardiogenic shock, severe hypotension, cardiac arrest
• Increases heart rate and blood pressure
Adverse effects: palpitations, tachycardia, HTN, dyspnea, necrosis or
gangrene if infiltrated, V-fib pulmonary edema
Interactions: increased effect with TCA/MAOI, decreased with BB,
dysrhythmia with digoxin
Direct stimulation of alpha and
beta1receptors (vasoconstriction),
No beta2 activity – DO NOT USE
FOR ANAPHYLAXIS
Indications: hypotensive states
Adverse effects: tachycardia
Alpha-adrenergic receptor
Indications: hypotension,
paroxysmal SVT
Also used as topical ophthalmic
treatment, nasal decongestant
• Vasoconstriction causes
decrease in secretions
Albuterol
(Proventil, Ventolin)
Beta2-adrenergic
agonist
PO or INH
Therapeutic Use: treat
bronchospasm, asthma,
bronchitis, and COPD
• Goal is to normalize breathing
rate, increase oxygen saturation,
less wheezing, patient is not
short of breath
Stimulates beta2-adrenergic
receptors in the lungs, which
relaxes the bronchial smooth
muscle resulting in bronchodilation
Side effects: tremor, nervousness, dizziness, sweating,
blurred vision, flushing, headache, hoarseness,
insomnia, tachy, hyperglycemia, HTN, SJ Syndrome
Contraindications: cardiac dysrhythmias, coronary
artery disease (CAD)
Caution: severe cardiac disease, HTN,
hyperthyroidism, DM, renal dysfunction, elderly,
pregnancy
Central-Acting Alpha Agonists
Clonidine (Catapress) – used to treat HTN
Beta adrenergic
Beta 1
(heart)
Increases heart rate and force of
contraction; increases renin secretion,
which increases blood pressure
- Stimulation of the beta 1 receptors
increases myocardial contractility and
heart rate
Beta 2
(lungs, visceral organs)
Dilates bronchioles; promotes
gastrointestinal and uterine
relaxation; promotes increase in blood
sugar through glycogenolysis in liver;
increases blood flow in skeletal
muscles
Alpha adrenergic
Located in blood vessels, eye, bladder,
and prostate
Alpha 1
(tissue, muscles, organs)
When alpha 1 receptors in vascular
tissues of muscles are stimulated, the
arterioles and venules constrict,
increasing peripheral resistance and
blood return to the heart. Circulation is
improved, and blood pressure is
increased.
Document Summary
Adrenergic drugs stimulate the sympathetic nervous system and are called adrenergics, adrenergic agonists, or sympathomimetics, because they mimic the sympathetic neurotransmitters norepinephrine and epinephrine. Increases heart rate and force of contraction; increases renin secretion, which increases blood pressure. Stimulation of the beta 1 receptors increases myocardial contractility and heart rate. Dilates bronchioles; promotes gastrointestinal and uterine relaxation; promotes increase in blood sugar through glycogenolysis in liver; increases blood flow in skeletal muscles. Vasoactive adrenergic: primarily cardiovascular side effects, watch for tachycardia and palpitations. Used to support failing heart or treatment of shock: failing heart: shortness of breath, fluid overload, tachycardia, shock: hypotension, high heart rate (but heart does not fill. Located in blood vessels, eye, bladder, and prostate. When alpha 1 receptors in vascular tissues of muscles are stimulated, the arterioles and venules constrict, increasing peripheral resistance and blood return to the heart.
