AUTONOMIC NERVOUS SYSTEM Adrenergic Drugs
Dec 27, 2015
AUTONOMIC NERVOUS SYSTEM
Adrenergic Drugs
ANS - Adrenergic Drugs
Describe the adrenergic drug effects on major body systems.
Discuss the nursing process related to the care of patients receiving adrenergic drugs for cardiovascular, respiratory, gastrointestinal, and genitourinary systems.
ANS - Adrenergic Drugs
Drugs that stimulate the sympathetic nervous system (SNS)
Adrenergic agonists Sympathomimetics
Mimic the effects of the SNS neurotransmitters: norepinephrine (NE)
epinephrine (EPI) dopamine
ANS - Adrenergic Drugs
ANS - Adrenergic DrugsAdrenergic Receptors
Located throughout the body Are receptors for the sympathetic
neurotransmitters (alpha)-adrenergic receptors (beta)-adrenergic receptors Dopaminergic receptors: respond only to
dopamine
ANS - Adrenergic Drugs-Adrenergic Receptors
Divided into 1 and 2 receptors Differentiated by their location on nerves
1-Adrenergic Receptors Located on postsynaptic effector cells
(the cell, muscle, or organ that the nerve stimulates)
2-Adrenergic Receptors Located on presynaptic nerve terminals
(the nerve that stimulates the effector cells) Control the release of neurotransmitters
Predominant -Adrenergic Agonist Responses Vasoconstriction CNS stimulation
ANS - Adrenergic Drugs-Adrenergic Receptors
All are located on postsynaptic effector cells 1-adrenergic receptors—located primarily in the heart 2-adrenergic receptors—located in smooth muscle of
the bronchioles, arterioles, and visceral organs -Adrenergic Agonist Response
Results in: Bronchial, GI, and uterine smooth muscle relaxation Glycogenolysis Cardiac stimulation
ANS - Adrenergic DrugsDopaminergic Receptors
An additional adrenergic receptor Stimulated by dopamine Causes dilation of the following blood
vessels, resulting in increased blood flow Renal Mesenteric Coronary Cerebral
ANS - Adrenergic DrugsResponses to Stimulation
Location Receptor Response
Cardiovascular:Blood vessels 1 Constriction
2 DilationCardiac muscle 1 Increased contractility
AV Node 1 Increased heart rate
SA Node 1 Increased heart rate
Gastrointestinal: Muscle: 2 Decreased motilitySphincters: 1 Constriction
ANS - Adrenergic DrugsResponses to Stimulation
(cont’d)Location Receptor Response
Genitourinary:Bladder sphincter 1 Constriction
Penis 1 Ejaculation
Uterus 1 Contraction2 Relaxation
Respiratory:Bronchial muscles 2 Dilation
Liver 2 Glycogenolysis
Pupils 1 Dilation
ANS - Adrenergic DrugsCatecholamines
Substances that can produce a sympathomimetic response
Endogenous epinephrine, norepinephrine, dopamine
Synthetic dobutamine, phenylephrine
Mechanism of Action: Direct-acting sympathomimetic
Binds directly to the receptor and causes a physiologic response
ANS - Adrenergic DrugsResponse to Direct-Acting
Sympathomimetics
ANS - Adrenergic DrugsIndirect-acting
sympathomimetic
Indirect-acting sympathomimetic
Causes the release of catecholamine from the storage sites (vesicles) in the nerve endings
The catecholamine then binds to the receptors and causes a physiologic response
ANS - Adrenergic DrugsIndirect-acting
sympathomimetic
ANS - Adrenergic Drugs –Stimulation of -adrenergic
receptors Stimulation of -adrenergic receptors on smooth muscles results in: Vasoconstriction of blood vessels Relaxation of GI smooth muscles Contraction of the uterus and bladder Male ejaculation Decreased insulin release Contraction of the ciliary muscles of the eye (dilated pupils)
ANS - Adrenergic Drugs Stimulation of 1-adrenergic
receptors
Stimulation of 1-adrenergic receptors on the myocardium, AV node, and SA node results in cardiac stimulation
Increased force of contraction (positive inotropic effect)
Increased heart rate (positive chronotropic effect)
Increased conduction through the AV node (positive dromotropic effect)
ANS - Adrenergic Drugs Stimulation of 2-adrenergic
receptors
Stimulation of 2-adrenergic receptors on the airways results in: Bronchodilation (relaxation of the bronchi)
Other effects of 2-adrenergic stimulation: Uterine relaxation Glycogenolysis in the liver Increased renin secretion in the kidneys
ANS - Adrenergic Drugs 2-Adrenergic Drugs
Examples: Tx of acute bronchospasm (Asthma, COPD)
albuterol (Proventil, Ventolin) epinephrine (Adrenalin) levalbuterol (Xopenex) metaproterenol (Alupent, Metaprel) ephedrine salmeterol (Serevent)
terbutaline* (Brethine, Brethaire)* Used to stop premature labor—causes relaxation of uterine smooth muscle
ANS - Adrenergic Drugs Reduction of intraocular
pressure Reduction of intraocular pressure and
causes mydriasis (pupil dilation): treatment of open-angle glaucoma or 2 receptors, or both
– Examples: epinephrine and dipivefrin
Temporary relief of conjunctival congestion (eyes) -adrenergic receptors Examples: – epinephrine (Primatene, Bronkaid)
– phenylephrine (Neo-Synephrine)
– tetrahydrozoline (Tyzine)
ANS - Adrenergic Drugs Nasal decongestant
Nasal decongestant Intranasal (topical) application causes
constriction of dilated arterioles and reduction of nasal blood flow, thus decreasing congestion
1-adrenergic stimulation
Topical Nasal Decongestants
tetrahydrozoline (Tyzine) epinephrine (Adrenalin) ephedrine phenylephrine (Neo-Synephrine)
ANS - Adrenergic DrugsVasoactive Sympathomimetics
( Pressors, (Inotropes, cardioselective sympathomimetics)
Used to support the heart during cardiac failure or shock; various and receptors affected
Pressors: dobutamine (Dobutrex) ephedrine fenoldopam (Corlopam) methoxamine Dopamine (Intropin)Epinephrine (Adrenalin)Norepinephrine (Levophed)Phenylephrine (Neo-Synephrine)
ANS - Adrenergic Drugs -Adrenergic Adverse
Effects CNS
Headache, restlessness, excitement, insomnia, euphoria
Cardiovascular Palpitations (dysrhythmias), tachycardia,
vasoconstriction, hypertension
Other Loss of appetite, dry mouth, nausea, vomiting,
taste changes (rare)
ANS - Adrenergic Drugs -Adrenergic Adverse
Effects CNS
Mild tremors, headache, nervousness, dizziness
Cardiovascular Increased heart rate, palpitations
(dysrhythmias), fluctuations in BP
Other Sweating, nausea, vomiting, muscle cramps
ANS - Adrenergic Drugs Interactions
Anesthetic drugs
Tricyclic antidepressants
MAOIs
Antihistamines
Thyroid preparations
Antihypertensives
ANS - Adrenergic Drugs Nursing Implications
Assess for allergies and history of hypertension, cardiac dysrhythmias, or other cardiovascular disease
Assess renal, hepatic, and cardiac function before treatment
Perform baseline assessment of vital signs, peripheral pulses, skin color, temperature; include postural blood pressure and pulse
Follow administration guidelines carefully
Intravenous administration Check IV site often for infiltration Use clear IV solutions / Use an infusion pump Infuse drug slowly to avoid dangerous cardiovascular
effects Monitor cardiac rhythm
ANS - Adrenergic Drugs Nursing Implications
(cont’d) With chronic lung disease:
Instruct patients to avoid factors that exacerbate their condition
Encourage fluid intake (up to 3000 mL per day) if permitted
Educate about proper dosing, use of equipment (MDI, spacer, nebulizer), and equipment care
ANS - Adrenergic Drugs Nursing Implications
(cont’d) Salmeterol is indicated for prevention of bronchospasms, not management of acute symptoms Overuse of nasal decongestants may cause rebound nasal congestion or ulcerations
Avoid OTC or other medications because of possible interactions
Administering two adrenergic drugs together may precipitate severe cardiovascular effects such as tachycardia or hypertension
ANS - Adrenergic Drugs Nursing Implications
(cont’d) Monitor for therapeutic effects: (cardiovascular uses)
Decreased edema Increased urinary output Return to normal vital signs Improved skin color and temperature Increased LOC
ANS - Adrenergic Drugs Nursing Implications
(cont’d) Monitor for therapeutic effects(bronchospasm/asthma):
Return to normal respiratory rate Improved breath sounds, fewer rales Increased air exchange Decreased cough Less dyspnea Improved blood gases Increased activity tolerance