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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.
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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 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 LocationReceptorResponse Cardiovascular: Blood vessels 1 Constriction 2 Dilation Cardiac muscle 1 Increased contractility AV Node 1 Increased heart rate SA Node 1 Increased heart rate Gastrointestinal: Muscle: 2 Decreased motility Sphincters: 1 Constriction
ANS - Adrenergic DrugsResponses to Stimulation (cont’d) LocationReceptorResponse 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 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 DrugsStimulation 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 DrugsStimulation 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, cardioselectivesympathomimetics) • 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