1. Drugs Affecting Autonomic Nervous System 1

2. Lecture objectives Identify the anatomy of nervous system.
Identify the drugs that effect ANS

4. Nervous System Divisions

6. Nervous System Overview
Brain
Spinal cord
Nerves
Functions of nervous system
Regulates and coordinates all body activities
Center of all mental activity, including thought, learning, and memory

7. Nervous System Divisions
Central Nervous System (CNS)
Brain
Spinal Cord
Processes and stores sensory and motor information
Controls consciousness
Peripheral Nervous System (PNS)
12 Pairs of Cranial Nerves
31 Pairs of Spinal Nerves
Transmits sensory and motor impulses back and forth between CNS and rest of body

8. Peripheral Nervous System
Somatic Nervous System (SNS)
Provides voluntary control over skeletal muscle contractions
Autonomic Nervous System (ANS)
Provides involuntary control over smooth muscle, cardiac muscle, and glandular activity and secretions in response to the commands of the central nervous system

9. Autonomic Nervous System
Sympathetic nerves
Increase heart rate
Constrict blood vessels
Raise blood pressure
Fight-or-flight response
Parasympathetic nerves
Slow heart rate
Increase peristalsis of intestines
Increase glandular secretions
Relax sphincters

10. Catecholamines Substances that can produce a sympathomimetic response
Endogenous:
Dopamine (Dopaminergic) epinephrine & norepinephrine (Adrenegeric)
2. Synthetic:
isoproterenol, dobutamine, phenylephrine

11. Fight or Flight Response:
These catecholamine hormones facilitate immediate physical reactions These include the following:
Acceleration of heart and lung action･Inhibition of stomach and intestinal action
Constriction of blood vessels in many parts of the body
Dilation of blood vessels for muscles
Inhibition of tear glands and salivation
Dilation of pupil
Relaxation of bladder
Inhibition of erection

12. 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. Adrenergic Agents
Drugs that stimulate the sympathetic nervous system (SNS)
Also known as:
adrenergic agonists or sympathomimetics
Mimic the effects of the SNS neurotransmitters:
norepinephrine (NE) and epinephrine (EPI)

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

15. Types of -adrenergic receptor
-adrenergic receptors are adrenergic receptors that respond to norepinephrine and to such blocking agents as phenoxybenzamine.
They are subdivided into two types:
1, found in smooth muscle, heart, and liver, with effects including vasoconstriction, intestinal relaxation, uterine contraction and pupillary dilation,
2, found in platelets, vascular smooth muscle, nerve termini, and pancreatic islets, with effects including platelet aggregation, vasoconstriction, and inhibition of norepinephrine release and of insulin secretion.

16. -receptor types
-adrenergic receptors respond particularly to epinephrine and to such blocking agents as propranolol.
There are three known types of beta receptor, designated β1, β2 and β3.
β1-Adrenergic receptors are located mainly in the heart.
β2-Adrenergic receptors are located mainly in the lungs, gastrointestinal tract, liver, uterus, vascular smooth muscle, and skeletal muscle.
β3-receptors are located in fat cells.

17. What do the receptors do
What do the receptors do? Activation of  receptors leads to smooth muscle contraction Activation of 2 receptors leads to smooth muscle relaxation Activation of 1 receptors leads to smooth muscle contraction (especially in heart)

18. Clinical Utility of drugs which affect the adrenergic nervous system:
a. Agonists of the 2 receptors are used in the treatment of asthma (relaxation of the smooth muscles of the bronchi)
b. Antagonists of the 1 receptors are used in the treatment of hypertension and angina (slow heart and reduce force of contraction)
c. Antagonists of the 1 receptors are known to cause lowering of the blood pressure (relaxation of smooth muscle and dilation of the blood vessels)

19. 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)

21. 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

23. 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) automaticity

24. Adrenergic Agents: Therapeutic Uses
Anorexiants: adjuncts to diet in the short-term management of obesity
Examples: benzaphetamine phentermine dextroamphetamine Dexedrine
2.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

25. Adrenergic Agents: Therapeutic Uses
3. Reduction of intraocular pressure and mydriasis (pupil dilation): treatment of open-angle glaucoma
Examples: epinephrine and dipivefrin
4. 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

26. 5. Ophthalmic relieving conjunctival congestion.
Examples: epinephrine naphazoline phenylephrine tetrahydrozoline
6. Vasoactive sympathomimetics also called cardio selective sympathomimetics
Used to support the heart during cardiac failure or shock.
Examples:
dobutamine dopamine ephedrine epinephrine fenoldopam isoproterenol methoxamine norepinephrine phenylephrine

27. 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)

28. 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

29. 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.

30. 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.

31. Adrenergic Agents: Nursing Implications
Overuse of nasal decongestants may cause rebound nasal congestion or ulcerations.
Monitor for therapeutic effects (cardiovascular uses):
Decreased edema
Increased urinary output
Return to normal vital signs
Improved skin color and temperature
Increased LOC

32. 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

33. Adrenergic-Blocking Agents
Bind to adrenergic receptors, but inhibit or block stimulation of the sympathetic nervous system (SNS)
Have the opposite effect of adrenergic agents
Also known as
adrenergic antagonists or sympatholytics

34. 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

35. 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

36. Beta Blockers: Therapeutic Uses
Anti-angina:decreases demand for myocardial oxygen
Cardioprotective:inhibits stimulation by circulating catecholamines
Class II antidysrhythmic
Antihypertensive
Treatment of migraine headaches
Glaucoma (topical use)

37. Adrenergic Blocking Agents: Nursing Implications
Assess for allergies and history of COPD, hypotension, cardiac dysrhythmias, bradycardia, CHF, or other cardiovascular problems
Remember that alpha blockers may precipitate hypotension.
Remember that beta blockers may precipitate bradycardia, hypotension, heart block, CHF, and bronchoconstriction.

38. Encourage patients to take medications as prescribed.
These medications should never be stopped abruptly.
Report constipation or the development of any urinary or bladder distention.
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.

39. 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

40. Monitor for side effects, including:
Hypotension
Fatigue
Tachycardia (alpha blockers)
Lethargy
Bradycardia
Depression
Heart block
Insomnia
CHF
nightmares
Increased airway resistance

41. QUESTION?