1. Drugs Affecting The Autonomic Nervous System
Adrenergic Agents and Adrenergic-Blocking Agents

2. Instructors may choose to insert EIC Image #48: The Sympathetic Nervous System in Relationship to the Entire Nervous System

3. Adrenergic Agents
Drugs that stimulate the sympathetic nervous system (SNS)

4. Adrenergic Agents Also known as
adrenergic agonists or sympathomimetics

5. Adrenergic Agents Mimic the effects of the SNS neurotransmitters:
norepinephrine (NE) and epinephrine (EPI)

6. Adrenergic Receptors Located throughout the body
Are receptors for the sympathetic neurotransmitters
Alpha-adrenergic receptors: respond to NE
Beta-adrenergic receptors: respond to EPI

7. Alpha-Adrenergic Receptors
Divided into alpha1 and alpha2 receptors
Differentiated by their location on nerves

8. Alpha1-Adrenergic Receptors
Located on postsynaptic effector cells (the cell, muscle, or organ that the nerve stimulates)

9. Alpha2-Adrenergic Receptors
Located on presynaptic nerve terminals (the nerve that stimulates the effector cells)
Control the release of neurotransmitters

10. The predominant alpha-adrenergic agonist responses are:
Vasoconstriction and CNS stimulation

11. 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

12. The beta-adrenergic agonist response results in:
Bronchial, GI, and uterine smooth muscle relaxation
Glycogenolysis
Cardiac stimulation

13. 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

14. Adrenergic Receptor Responses to Stimulation
LOCATION RECEPTOR RESPONSE Cardiovascular
Blood vessels alpha1 and beta2 Constriction / dilation
Cardiac muscle beta1 Increased contractility
AV Node beta1 Increased heart rate
SA Node beta1 Increased heart rate

15. Adrenergic Receptor Responses to Stimulation
LOCATION RECEPTOR RESPONSE Gastrointestinal
Muscle beta2 Decreased motility
Sphincters alpha1 Constriction

16. Adrenergic Receptor Responses to Stimulation
LOCATION RECEPTOR RESPONSE Genitourinary
Bladder alpha1 Constriction sphincter
Penis alpha1 Ejaculation
Uterus alpha1 and beta2 Contraction/ relaxation

17. Adrenergic Receptor Responses to Stimulation
LOCATION RECEPTOR RESPONSE Respiratory
Bronchial beta2 Dilation/relaxation muscles

18. Catecholamines Endogenous: Synthetic:
Substances that can produce a sympathomimetic response
Endogenous:
epinephrine, norepinephrine,dopamine
Synthetic:
isoproterenol, dobutamine, phenylephrine

19. Adrenergic Agents Mechanism of Action
Direct-acting sympathomimetic:
Binds directly to the receptor and causes a physiologic response

20. Instructors may choose to insert EIC Image #52: Direct-Acting Sympathomimetics

21. Adrenergic Agents Mechanism of Action
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

22. Instructors may choose to insert EIC Image #53: Indirect-Acting Sympathomimetics

23. Adrenergic Agents Mechanism of Action
Mixed-acting sympathomimetic:
Directly stimulates the receptor by binding to it
AND
Indirectly stimulates the receptor by causing the release of stored neurotransmitters from the vesicles in the nerve endings

24. Instructors may choose to insert EIC Image #54: Mixed-Acting Sympathomimetics

25. Drug Effects of Adrenergic Agents
Stimulation of alpha-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)

26. Drug Effects of Adrenergic Agents
Stimulation of beta2-adrenergic receptors on the airways results in:
Bronchodilation (relaxation of the bronchi)
Uterine relaxation
Glycogenolysis in the liver

27. Drug Effects of Adrenergic Agents
Stimulation of beta1-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)

28. Adrenergic Agents: Therapeutic Uses
Anorexiants: adjuncts to diet in the short-term management of obesity
Examples: benzphetamine phentermine dextroamphetamine Dexedrine

29. Adrenergic Agents: Therapeutic Uses
Bronchodilators: treatment of asthma and bronchitis
Agents that stimulate beta2-adrenergic receptors of bronchial smooth muscles causing relaxation
Examples:
albuterol ephedrine epinephrine isoetharine isoproterenol levalbuterol metaproterenol salmeterol terbutaline
These agents may also affect uterine and vascular smooth muscles.

30. Adrenergic Agents: Therapeutic Uses
Reduction of intraocular pressure and mydriasis (pupil dilation): treatment of open-angle glaucoma
Examples: epinephrine and dipivefrin

31. Adrenergic Agents: Therapeutic Uses
Nasal decongestant:
Intranasal (topical) application causes constriction of dilated arterioles and reduction of nasal blood flow, thus decreasing congestion.
Examples: epinephrine ephedrine naphazoline phenylephrine tetrahydrozoline

32. Adrenergic Agents: Therapeutic Uses
Ophthalmic
Topical application to the eye surface affects the vasculature of the eye, stimulating alpha receptors on small arterioles, thus relieving conjunctival congestion.
Examples: epinephrine naphazoline phenylephrine tetrahydrozoline

33. Adrenergic Agents: Therapeutic Uses
Vasoactive sympathomimetics (pressors, inotropes), also called cardioselective sympathomimetics
Used to support the heart during cardiac failure or shock.
Examples:
dobutamine dopamine ephedrine epinephrine fenoldopam isoproterenol methoxamine norepinephrine phenylephrine

34. Adrenergic Agents: Side Effects
Alpha-Adrenergic Effects
CNS:
headache, restlessness, excitement, insomnia, euphoria
Cardiovascular:
palpitations (dysrhythmias), tachycardia, vasoconstriction, hypertension
Other:
anorexia, dry mouth, nausea, vomiting, taste changes (rare)

35. Adrenergic Agents: Side Effects
Beta-Adrenergic Effects
CNS:
mild tremors, headache, nervousness, dizziness
Cardiovascular:
increased heart rate, palpitations (dysrhythmias), fluctuations in BP
Other:
sweating, nausea, vomiting, muscle cramps

36. Adrenergic Agents: Interactions
Anesthetic agents
Tricyclic antidepressants
MAOIs
Antihistamines
Thyroid preparations
Antihypertensives
Will directly antagonize another adrenergic agent, resulting in reduced effects

37. Adrenergic Agents: 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, and capillary refill. Include postural blood pressure and pulse.
Follow administration guidelines carefully.

38. Adrenergic Agents: Nursing Implications
IV administration:
Check IV site often for infiltration
Use clear IV solutions
Use an infusion device/IV pump
Infuse agent slowly to avoid dangerous cardiovascular effects
Monitor cardiac rhythm

39. Adrenergic Agents: Nursing Implications
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 and equipment care.
Salmeterol is indicated for PREVENTION of bronchospasms, not management of acute symptoms.

40. Adrenergic Agents: Nursing Implications
Overuse of nasal decongestants may cause rebound nasal congestion or ulcerations.
Avoid OTC or other medications because of possible interactions.
Administering two adrenergic agents together may precipitate severe cardiovascular effects such as tachycardia or hypertension.
Inform patients taking inhaled isoproterenol that their sputum or saliva may turn pink.

41. Adrenergic Agents: Nursing Implications
Monitor for therapeutic effects (cardiovascular uses):
Decreased edema
Increased urinary output
Return to normal vital signs
Improved skin color and temperature
Increased LOC

42. Adrenergic Agents: Nursing Implications
Monitor for therapeutic effects (asthma):
Return to normal respiratory rate
Improved breath sounds, fewer rales
Increased air exchange
Decreased cough
Less dyspnea
Improved blood gases
Increased activity tolerance

43. Adrenergic-Blocking Agents
Bind to adrenergic receptors, but inhibit or block stimulation of the sympathetic nervous system (SNS)

44. Adrenergic Blocking Agents
Have the opposite effect of adrenergic agents
Also known as
adrenergic antagonists or sympatholytics

45. Adrenergic Blocking Agents
Sympatholytics inhibit—or LYSE—sympathetic neurotransmitters (norepinephrine and epinephrine)

46. Adrenergic Blocking Agents
Classified by the type of adrenergic receptor they block
Alpha1 and alpha2 receptors
Beta1 and beta2 receptors

47. Instructors may choose to insert EIC Image #55: Alpha-Blocker Mechanisms

48. Adrenergic-Blocking Agents: Drug Effects and Therapeutic Uses
Ergot Alkaloids (Alpha-Blockers)
Constrict dilated arteries going to the brain (carotid arteries)
Used to treat vascular headaches (migraines)
Stimulate uterine contractions by inducing vasoconstriction
Used to control postpartum bleeding

49. Adrenergic-Blocking Agents: Drug Effects and Therapeutic Uses
Alpha-Blockers
Cause both arterial and venous dilation, reducing peripheral vascular resistance and BP
Used to treat hypertension
Effect on receptors on prostate gland and bladder decreased resistance to urinary outflow, thus reducing urinary obstruction and relieving effects of BPH

50. Adrenergic-Blocking Agents: Drug Effects and Therapeutic Uses
Alpha-Blockers
Phentolamine
Quickly reverses the potent vasoconstrictive effects of extravasated vasopressors such as norepinephrine or epinephrine.
Restores blood flow and prevents tissue necrosis.

51. Adrenergic-Blocking Agents: Side Effects
Alpha Blockers
Body System Side/Adverse Effects
Cardiovascular Palpitations, orthostatic hypotension, tachycardia, edema, dysrhythmias, chest pain
CNS Dizziness, headache, drowsiness, anxiety, depression, vertigo, weakness, numbness, fatigue

52. Adrenergic-Blocking Agents: Side Effects
Alpha Blockers
Body System Side/Adverse Effects
Gastrointestinal Nausea, vomiting, diarrhea, constipation, abdominal pain
Other Incontinence, nose bleeding, tinnitus, dry mouth, pharyngitis, rhinitis

53. Beta Blockers Block stimulation of beta receptors in the SNS
Compete with norepinephrine and epinephrine
Selective and nonselective beta blockers

54. Beta Receptors Beta1 Receptors Located primarily on the heart
Beta blockers selective for these receptors are called cardioselective beta blockers

55. Beta Receptors Beta2 Receptors
Located primarily on smooth muscles of bronchioles and blood vessels

56. Nonspecific Beta Blockers
Beta blockers that block both beta1 and beta2 receptors

57. Beta Blockers: Mechanism of Action
Cardioselective (Beta1)
Decreases heart rate
Prolongs SA node recovery
Slows conduction rate through the AV node
Decreases myocardial contractility, thus decreasing myocardial oxygen demand

58. Beta Blockers: Mechanism of Action
Nonspecific (Beta1 and Beta2)
Effects on heart: Same as cardioselective
Bronchioles: Constriction, resulting in narrowing of airways and shortness of breath
Blood vessels: Vasoconstriction

59. Beta Blockers: Therapeutic Uses
Anti-angina: decreases demand for myocardial oxygen
Cardioprotective: inhibits stimulation by circulating catecholamines
Class II antidysrhythmic

60. Beta Blockers: Therapeutic Uses
Antihypertensive
Treatment of migraine headaches
Glaucoma (topical use)

61. Beta Blockers: Side Effects
Body System Side/Adverse Effects
Blood Agranulocytosis, thrombocytopenia
Cardiovascular AV block, bradycardia, congestive heart failure, peripheral vascular insufficiency
CNS Dizziness, mental depression, lethargy, hallucinations

62. Adrenergic-Blocking Agents: Side Effects
Beta Blockers
Body System Side/Adverse Effects
Gastrointestinal Nausea, dry mouth, vomiting, diarrhea, cramps, ischemic colitis
Other Impotence, rash, alopecia, bronchospasms

63. Adrenergic Blocking Agents: Nursing Implications
Assess for allergies and history of COPD, hypotension, cardiac dysrhythmias, bradycardia, CHF, or other cardiovascular problems
Any preexisting condition that might be exacerbated by the use of these agents might be a CONTRAINDICATION to their use.

64. Adrenergic Blocking Agents: Nursing Implications
Remember that alpha blockers may precipitate hypotension.
Remember that beta blockers may precipitate bradycardia, hypotension, heart block, CHF, and bronchoconstriction.

65. Adrenergic Blocking Agents: Nursing Implications
Avoid OTC medications because of possible interactions.
Possible drug interactions may occur with:
Antacids (aluminum hydroxide type)
Antimuscarinics/anticholinergics
Diuretics and cardiovascular drugs
Neuromuscular blocking agents
Oral hypoglycemic agents

66. Adrenergic Blocking Agents: Nursing Implications
Encourage patients to take medications as prescribed.
These medications should never be stopped abruptly.
Report constipation or the development of any urinary hesitancy or bladder distention.

67. Adrenergic Blocking Agents: Nursing Implications
Teach patients to change positions slowly to prevent or minimize postural hypotension.
Avoid caffeine (excessive irritability).
Avoid alcohol ingestion and hazardous activities until blood levels become stable.
Patients should notify their physician if palpitations, dyspnea, nausea, or vomiting occur.

68. Beta Blocking Agents: Nursing Implications
Rebound hypertension or chest pain may occur if this medication is discontinued abruptly.
Patients should notify their physician if they become ill and unable to take medication.
Inform patients that they may notice a decrease in their tolerance for exercise; dizziness and fainting may occur with increased activity. Notify the physician if these problems occur.

69. Beta Blocking Agents: Nursing Implications
Patients should report the following to their physician:
Weight gain of more than 2 pounds (1 kg) within a week
Edema of the feet or ankles
Shortness of breath
Excessive fatigue or weakness
Syncope or dizziness

70. Adrenergic Blocking Agents: Nursing Implications
Monitor for side effects, including:
Hypotension Fatigue
Tachycardia (alpha blockers) Lethargy
Bradycardia Depression
Heart block Insomnia
CHF Vivid nightmares
Increased airway resistance

71. Adrenergic Blocking Agents: Nursing Implications
Monitor for therapeutic effects
Decreased chest pain in patients with angina
Return to normal BP and P
Other specific effects, depending on the use