Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Chapter 18 Adrenergic Drugs Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Adrenergic Drugs Drugs that stimulate the sympathetic nervous system (SNS) Also known as: Adrenergic agonists Sympathomimetics Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Characteristics Mimic the effects of SNS neurotransmitters (catecholamines) Norepinephrine (NE) Epinephrine (EPI) Dopamine Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Adrenergic Receptors Located throughout the body Are receptors for the sympathetic neurotransmitters Alpha-adrenergic receptors Beta-adrenergic receptors Dopaminergic receptors: respond only to dopamine Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Alpha-Adrenergic Receptors Divided into alpha1 and alpha2 receptors Differentiated by their location on nerves Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Alpha-Adrenergic Receptors (cont’d) Located on postsynaptic effector cells (the cell, muscle, or organ that the nerve stimulates) Alpha2-adrenergic receptors Located on presynaptic nerve terminals (the nerve that stimulates the effector cells) Control the release of neurotransmitters Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Alpha-Adrenergic Agonist Responses Vasoconstriction CNS stimulation Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Beta-Adrenergic Receptors All are located on postsynaptic effector cells Beta1-adrenergic receptors—located primarily in the heart Beta2-adrenergic receptors—located in smooth muscle of the bronchioles, arterioles, and visceral organs Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Beta-Adrenergic Agonist Responses Bronchial, GI, and uterine smooth muscle relaxation Glycogenolysis Cardiac stimulation Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Dopaminergic Receptors An additional adrenergic receptor Stimulated by dopamine Causes dilation of the following blood vessels, resulting in increased blood flow Renal Mesenteric Coronary Cerebral Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Responses to Stimulation Location Receptor Response Cardiovascular Blood vessels alpha1 Vasoconstriction beta2 Vasodilation Cardiac muscle beta1 Increased contractility AV node beta1 Increased heart rate SA node beta1 Increased heart rate Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Responses to Stimulation (cont’d) Location Receptor Response Gastrointestinal Muscle beta2 and alpha Decreased motility Sphincters alpha1 Constriction Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Responses to Stimulation (cont’d) Location Receptor Response Genitourinary Bladder alpha1 Constriction sphincter Penis alpha1 Ejaculation Uterus alpha1 Contraction beta2 Relaxation Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Responses to Stimulation (cont’d) Location Receptor Response Respiratory Bronchial beta2 Dilation muscles Endocrine Liver alpha1, beta2 Glycogenolysis Ocular Pupils alpha1 Dilation (mydriasis) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Catecholamines Substances that can produce a sympathomimetic response Endogenous Epinephrine, norepinephrine, dopamine Synthetic Dobutamine, phenylephrine Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Mechanism of Action Direct-acting sympathomimetic Binds directly to the receptor and causes a physiologic response Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Mechanism of Action (cont’d) Indirect-acting sympathomimetic Causes release of catecholamine from storage sites (vesicles) in nerve endings Catecholamine then binds to receptors and causes a physiologic response Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Mechanism of Action (cont’d) Mixed-acting sympathomimetic Directly stimulates the receptor by binding to it and Indirectly stimulates the receptor by causing the release of stored neurotransmitters from vesicles in the nerve endings Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Drug Effects Stimulation of alpha-adrenergic receptors on smooth muscles results in Vasoconstriction of blood vessels Relaxation of GI smooth muscles (decreased motility) Constriction of bladder sphincter Contraction of uterus Male ejaculation Contraction of pupillary muscles of the eye (dilated pupils) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Drug Effects (cont’d) Stimulation of beta1-adrenergic receptors on the myocardium, atrioventricular (AV) node, and sinoatrial (SA) node results in cardiac stimulation Increased force of contraction (positive inotropic effect) Increased heart rate (positive chronotropic effect) Increased conduction through AV node (positive dromotropic effect) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Drug Effects (cont’d) Stimulation of beta2-adrenergic receptors on the airways results in Bronchodilation (relaxation of the bronchi) Other effects of beta2-adrenergic stimulation Uterine relaxation Glycogenolysis in the liver Increased renin secretion in the kidneys Relaxation of GI smooth muscles (decreased motility) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Classroom Response Question A patient has two inhalers that are due to be taken at the same time. One is a bronchodilator. The other is a corticosteroid. Which inhaler should the patient take first? The bronchodilator The corticosteroid It does not matter which one is taken first. Correct answer: A Rationale: Taking the bronchodilator first will result in a more open airway and thus allow for better penetration by the inhaled corticosteroid. Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Elsevier items and derived items © 2009, 2005, 2001 by Saunders, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Indications Treatment of asthma and bronchitis Bronchodilators: drugs that stimulate beta2-adrenergic receptors of bronchial smooth muscles, causing relaxation, resulting in bronchodilation Examples: albuterol, ephedrine, epinephrine, formoterol, levalbuterol, metaproterenol, pirbuterol, salmeterol, and terbutaline* * Used to stop premature labor—causes relaxation of uterine smooth muscle Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Classroom Response Question A patient is experiencing bronchospasms after running half a mile. He has several inhalers with him. Which one would be appropriate for treatment at this time? albuterol salmeterol fluticasone salmeterol and fluticasone combination (Advair Diskus) Correct answer: A Rationale: Albuterol is a beta2 agonist that is used for acute bronchospasms. Salmeterol is appropriate for prevention of bronchospasms. Fluticasone is a corticosteroid that is not effective for acute bronchospasms. Advair Diskus is used for daily maintenance, not acute exacerbations. Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Elsevier items and derived items © 2009, 2005, 2001 by Saunders, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Indications (cont’d) Treatment of nasal congestion Intranasal (topical) application causes constriction of dilated arterioles and reduction of nasal blood flow, thus decreasing congestion Alpha1-adrenergic receptors Examples: ephedrine, naphazoline, oxymetazoline, phenylephrine, and tetrahydrozoline Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Indications (cont’d) Temporary relief of conjunctival congestion (eyes) Alpha-adrenergic receptors Examples: epinephrine, naphazoline, phenylephrine, tetrahydrozoline Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Indications (cont’d) Reduction of intraocular pressure and dilation of pupils: treatment of open-angle glaucoma Alpha-adrenergic receptors Examples: epinephrine and dipivefrin Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Vasoactive Adrenergics (Pressors, Inotropes) Also called cardioselective sympathomimetics Used to support the heart during cardiac failure or shock; various alpha and beta receptors affected Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Vasoactive Sympathomimetics (Pressors, Inotropes): Examples dobutamine ephedrine fenoldopam midodrine dopamine epinephrine phenylephrine norepinephrine Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Classroom Response Question A patient on a dobutamine drip starts to complain that her intravenous line “hurts.” The nurse checks the insertion site and sees that the area is swollen and cool. What will the nurse do first? Slow the intravenous infusion Stop the intravenous infusion Inject the area with phentolamine Notify the physician health care provider Correct answer: B Rationale: Infiltration of an intravenous solution containing an adrenergic drug may lead to tissue necrosis from excessive vasoconstriction around the intravenous site. Phentolamine is often used for the treatment of infiltration, but the first thing the nurse must do is to stop the infusion of the adrenergic drug. Slowing the medication will not stop further tissue damage. The physician should be notified, but the infusion should be stopped first. Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Elsevier items and derived items © 2009, 2005, 2001 by Saunders, an imprint of Elsevier Inc.

Alpha-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) Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Beta-Adrenergic Adverse Effects CNS Mild tremors, headache, nervousness, dizziness Cardiovascular Increased heart rate, palpitations (dysrhythmias), fluctuations in BP Other Sweating, nausea, vomiting, muscle cramps Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Interactions Anesthetic drugs Tricyclic antidepressants MAOIs Antihistamines Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Interactions (cont’d) Thyroid preparations Adrenergic antagonists Will directly antagonize each other, resulting in reduced effects Includes some antihypertensives Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Nursing Implications Assess for allergies, asthma, and history of hypertension, cardiac dysrhythmias, or other cardiovascular disease Assess renal, hepatic, and cardiac function before treatment Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Nursing Implications (cont’d) Perform baseline assessment of vital signs, peripheral pulses, skin color, temperature, and capillary refill; include postural blood pressure and pulse Follow administration guidelines carefully Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Classroom Response Question A patient on a dobutamine drip starts to complain that he feels a “tightness” in his chest that he had not felt before. What will the nurse do first? Check the infusion site for possible extravasation Increase the infusion rate Check the patient’s vital signs Order an electrocardiogram Correct answer: C Rationale: Before anything else is done, the patient’s vital signs should be checked for alterations. The dopamine rate should not be increased. Extravasation rarely causes chest tightness. While an electrocardiogram would be prudent, it's not the priority until after the vital signs demonstrate that the patient is stable. Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Elsevier items and derived items © 2009, 2005, 2001 by Saunders, an imprint of Elsevier Inc.

Nursing Implications (cont’d) 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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Nursing Implications (cont’d) With chronic lung disease Instruct patients to avoid factors that exacerbate their condition Encourage fluid intake (up to 3000 mL/day) if permitted Educate patients about proper dosing, use of equipment (metered-dose inhaler [MDI], spacer, nebulizer), and equipment care Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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 over-the-counter or other medications because of possible interactions Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Classroom Response Question A 10-year-old child is brought to the emergency department while having an asthma attack. She is given a nebulizer treatment with albuterol. The nurse’s immediate assessment priority would be to determine the time of the child’s last meal. monitor Spo2 with a pulse oximeter. monitor the child’s temperature. provide education on asthma management. Correct answer: B Rationale: During administration of albuterol, a fast-acting beta2 agonist, the nurse should monitor the patient’s respiratory status including Spo2 (with a pulse oximeter), respiratory rate, and breath sounds to ensure that the medication is having a therapeutic effect. The other items can be handled after her respiratory status is stable. Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Elsevier items and derived items © 2009, 2005, 2001 by Saunders, an imprint of Elsevier Inc.

Nursing Implications (cont’d) Administering two adrenergic drugs together may precipitate severe cardiovascular effects such as tachycardia or hypertension Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

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 Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Nursing Implications (cont’d) Monitor for therapeutic effects (asthma) Return to normal respiratory rate Improved breath sounds, fewer crackles Increased air exchange Decreased cough Less dyspnea Improved blood gases Increased activity tolerance Copyright © 2014 by Mosby, an imprint of Elsevier Inc.