Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. CHAPTER 18 Adrenergic Drugs

2 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Adrenergic Drugs  Drugs that stimulate the sympathetic nervous system (SNS)  Also known as:  Adrenergic agonists  Sympathomimetics

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4 Characteristics  Mimic the effects of SNS neurotransmitters (catecholamines)  Norepinephrine (NE)  Epinephrine (EPI)  Dopamine

5 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate 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

6 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Alpha-Adrenergic Receptors  Divided into alpha 1 and alpha 2 receptors  Differentiated by their location on nerves

7 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Alpha 1 -Adrenergic Receptors  Located on postsynaptic effector cells (the cell, muscle, or organ that the nerve stimulates)

8 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Alpha 2 -Adrenergic Receptors  Located on presynaptic nerve terminals (the nerve that stimulates the effector cells)  Control the release of neurotransmitters

9 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Alpha-Adrenergic Agonist Responses  Vasoconstriction  CNS stimulation

10 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Beta-Adrenergic Receptors  All are located on postsynaptic effector cells  Beta 1 -adrenergic receptors—located primarily in the heart  Beta 2 -adrenergic receptors—located in smooth muscle of the bronchioles, arterioles, and visceral organs

11 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Beta-Adrenergic Agonist Responses  Bronchial, GI, and uterine smooth muscle relaxation  Glycogenolysis  Cardiac stimulation

12 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate 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

13 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Responses to Stimulation LocationReceptor Response Cardiovascular Blood vesselsalpha 1 Constriction beta 2 Dilation Cardiac musclebeta 1 Increased contractility AV Nodebeta 1 Increased heart rate SA Nodebeta 1 Increased heart rate

14 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Responses to Stimulation (cont’d) LocationReceptorResponse Gastrointestinal Musclebeta 2 and alphaDecreased motility Sphinctersalpha 1 Constriction

15 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Responses to Stimulation (cont’d) LocationReceptorResponse Genitourinary Bladderalpha 1 Constriction sphincter Penisalpha 1 Ejaculation Uterusalpha 1 Contraction beta 2 Relaxation

16 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Responses to Stimulation (cont’d) LocationReceptorResponse Respiratory Bronchialbeta 2 Dilation muscles Liver beta 2 Glycogenolysis Pupils alpha 1 Dilation

17 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Catecholamines  Substances that can produce a sympathomimetic response  Endogenous  Epinephrine, norepinephrine, dopamine  Synthetic  Dobutamine, phenylephrine

18 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Mechanism of Action  Direct-acting sympathomimetic  Binds directly to the receptor and causes a physiologic response

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20 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

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22 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

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24 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)

25 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Drug Effects (cont’d)  Stimulation of beta 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 AV node (positive dromotropic effect)

26 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Drug Effects (cont’d)  Stimulation of beta 2 -adrenergic receptors on the airways results in  Bronchodilation (relaxation of the bronchi)  Other effects of beta 2 -adrenergic stimulation  Uterine relaxation  Glycogenolysis in the liver  Increased renin secretion in the kidneys  Relaxation of GI smooth muscles (decreased motility)

27 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Indications  Treatment of asthma and bronchitis  Bronchodilators: drugs that stimulate beta 2 - 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

28 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate 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

29 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Indications (cont’d)  Temporary relief of conjunctival congestion (eyes)  Alpha-adrenergic receptors  Examples: epinephrine, naphazoline, phenylephrine, tetrahydrozoline

30 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate 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  Alpha 1 -adrenergic receptors  Examples: epinephrine, ephedrine, naphazoline, oxymetazoline, phenylephrine, and tetrahydrozoline

31 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate 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

32 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Vasoactive Sympathomimetics (Pressors, Inotropes): Examples  Dobutamine  Ephedrine  Fenoldopam  Methoxamine  Others  Dopamine  Epinephrine  Phenylephrine  Norepinephrine

33 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate 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)

34 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate 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

35 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Interactions  Anesthetic drugs  Tricyclic antidepressants  MAOIs  Antihistamines

36 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Interactions (cont’d)  Thyroid preparations  Antihypertensives  Will directly antagonize another adrenergic drug, resulting in reduced effects

37 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Nursing Implications  Assess for allergies and history of hypertension, cardiac dysrhythmias, or other cardiovascular disease  Assess renal, hepatic, and cardiac function before treatment

38 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate 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

39 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate 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

40 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate 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 (MDI, spacer, nebulizer), and equipment care

41 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate 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

42 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Nursing Implications (cont’d)  Administering two adrenergic drugs together may precipitate severe cardiovascular effects such as tachycardia or hypertension

43 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate 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

44 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate 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