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

2. 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.

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

4. 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.

5. 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.

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

7. 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.

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

9. 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.

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

11. 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.

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

13. 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.

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

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

16. 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.

17. 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.

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

19. 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.

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

21. 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.

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

23. 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.

24. 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.

25. 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.

26. 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.

27. 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.

28. 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.

29. 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.

30. 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.

31. 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.

32. 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.

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

34. 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.

35. 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.

36. 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.

37. 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.

38. 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.

39. 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.

40. 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.

41. 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.

42. 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.

43. 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.

44. 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.

45. 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.

46. 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.

47. 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.

48. 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.