Drugs Affecting the Nervous System

1. Drugs Affecting the Nervous System Jane Bordner, Rn BSN Instructor of Nursing HACC Central Pennsylvania’s Community College Nursing 102 Fall 2012

2. Nervous System Review • 2 Major divisions • CNS • PNS

4. The Central and Autonomic Nervous Systems • Central nervous system (CNS) • Made up of brain and spinal cord • Receives signals from sensory receptors (vision, pressure, pain, cold, warmth, touch, smell)

5. The Central and Autonomic Nervous Systems • PNS • 2 Divisions • Somatic- voluntary-conscious control • Autonomic- involuntary-unconscious control • Sympathetic- fight or flight epinephrine/norepinephrine • Parasympathetic- rest or digest • acteylocholine • 2 Types of Nerves • Afferent – to the brain • Efferent-from sensory organs

6. The Central and Autonomic Nervous Systems (cont’d) • Peripheral nervous system • Afferent nerves—transmit signals to the spinal cord and brain • Efferent nerves—carry impulses from CNS to other parts of body.

7. Autonomic Nervous System (ANS) • 2 systems often have opposing functions • Stimulate or inhibit • Most organ are innervated by both

8. Autonomic Nervous System • Sympathetic - Adrenergic • “Fight or Flight”

9. Sympathetic Nervous System

10. Autonomic Nervous System • Parasympathetic -Cholinergic • “Rest and Digest”

11. Parasympathetic Nervous System

12. Synapses

13. Neurotransmitters

14. 1. Message travels along nerve; when it approaches nerve ending a neurotransmitter is released 2. Neurotransmitter is received by next cell 3. Some of neurotransmitter gets reabsorbed 4. When enough neurotransmitter is received by next nerve cell message moves forward

15. Messenger Molecule (hormone, neurotransmitter, or drug) Cell surface Cell surface Biochemical Response

16. Sympathetic • Major Neurotransmitters (Catecholamines) • Epinephrine • Norepinephrine • Dopamine

17. Effects of Sympathetic System • Increase heart rate • Relax bronchial smooth muscles • Pupil dilation • Increased metabolism • Decreased GI motility • Peripheral vasoconstriction

19. Neuroreceptors • Alpha 1: vasoconstriction of arterioles, relax bladder, eyes, liver • Alpha 2: skeletal blood vessels, pancreas • Beta 1: AV and SA node stimulation = increased heart rate and contraction strength • Beta 2: relaxes smooth muscle of bronchi and uterus • Dopaminergic

20. Sympathetic Neurotransmitters • Act on alpha, beta, or dopaminergic receptor sites • Example: • Alpha 1 receptors are found in peripheral blood vessels, when stimulated they cause peripheral vasoconstriction which leads to increased BP

21. Parasympathetic Activity • Major Neurotransmitter (Cholinergic) • Acetylcholine

22. Parasympathetic Neuroreceptors • Cholinergic receptors • Muscarinic • Both excitation and inhibition • Salivation • Lacrimation • Gastric acid secretion • Slow onset • Nicotinic • Excitation • Fast onset • Short duration

23. Parasympathetic Effects • Decrease heart rate • Constrict bronchial smooth muscle • Pupil constriction • Increased GI motility • Increased secretions • Increased bladder tone

24. Nicotinic Alpha Beta Muscarinic 1 2 1 2

25. Drug Effects • Drug effect depends on: • Specific receptor it interacts with • Number of receptors • Typeof receptors • Drug specificity • Antagonist = Block • Agonist = Stimulate

26. Drug Effects • Imitateneurotransmitters’ action • Blockneurotransmitters’ action • Enhance or inhibit • synthesis • storage • release • breakdown

27. Drug Categories • ANS drugs are categorized by • Site of action • Effect • Receptor

28. Drug Categories • Sympathomimetics • Adrenergics • Sympatholytics • Adrenergic blockers • Parasympathomimetics • Cholinergics • Parasympatholytics • Cholinergic blockers

29. SympathomimeticsAKAAdrenergic Agents

30. Sympathomimetics/ Adrenergic Agents • Catecholamines • Noncatecholamines • Primary Actions • Increase heart rate • Increase BP • Relax bronchial smooth muscle • Relax GI tract • Coronary artery vasodilation • Peripheral vascular vasoconstriction

31. Catecholamines • Stimulate alpha and betareceptors • Mimic action of epinephrine, norepinephrine, and dopamine • Examples: • dobutamine HCL (Dobutrex, Intropin, Dopastat ) • Epinephrine (Adrenalin, EpiPen ) • Norepinephrine (Levophed) • isoproterenol HCL (Isuprel)

32. Catecholamines • Uses • Severe hypotensive crisis • Cardiac arrest • Anaphylactic shock • Special considerations • Destroyed by digestive enzymes

33. “Cat”echolamines • Side Effects • Severe throbbing headache • Dizziness • Anxiety • Fear • Palpitations • Hypertension

34. Noncatecholamines • Similar responses • More receptor selective • Slower acting • Longer lasting • Can be given PO • Usually given SC or by inhaler

35. Noncatecholamines • Examples • albuterol (Proventil) • metaproterenol sulfate (Alupent) • terbutaline (Brethine) • phenylephrine HCL (Neo-Synephrine) • Uses • Bronchospasm (Asthma/Emphysema) • Nasal congestion • Preterm labor

36. Bronchoconstriction

37. Noncatecholamines • Side Effects • Tachycardia • Palpitations • Tremors • Hypertension • Headache • Anxiety

38. Adrenergic Agents • Nursing Measures • Monitor VS frequently • Monitor breath sounds • Monitor blood glucose in Diabetic

39. SympatholyticsAKAAdrenergic blockers

40. Adrenergic Blocking Agents • AKA • Sympatholytics • Antiadrenergics • Antagonisticeffect • Classified by site of action • Alpha Adrenergic Blockers • Beta Adrenergic Blockers

41. Alpha Adrenergic Blocking Agents • Action • Relax smooth muscle • Peripheral vasodilation • Uses • Antihypertensives • Vascular H/A • Raynaud’s Disease • Buerger’s Disease

42. Alpha Adrenergic Blocking Agents • Side Effects • Hypotension • Tachycardia • Dizziness • H/A • Nursing Actions • Postural BP • Teach to avoid caffeine

43. Alpha Adrenergic Blocking Agents • Examples • ergotamine tartrate (Ergostat) • Inhaler, PO or SL • Treat migraine H/A • phenoxybenzamine HCL (Dibenzyline) • Antihypertensive • Treat Raynaud’s Disease • doxazosinmesylate (Cardura) • prazosin HCL (Minipress) • terazosin (Hytrin) • Arteriole and venous vasodilation lower BP

44. Beta Adrenergic Blocking Agents • AKA • Beta Blockers • Most widely usedgroup • Beta 1receptors = heart • Beta 2receptors = bronchi and blood vessels • Mixed= Nonselective blocking agents

45. Beta Adrenergic Blocking Agents • Effect • Lower HR • Decrease BP • Constrict pupil • Decrease production of aqueous humor • Uses • Cardiac Arrhythmias • HTN • Angina • Glaucoma

46. Beta Adrenergic Blocking Agents • Mixed • *labetalol (Normodyne) • Selective Beta-1 • esmolol (Brevibloc) • *metoprolol (Lopressor/Toprol XL/Betaloc ) • acebutolol (Sectral) • betaxolol (Kerlone) • bisoprolol (Zebeta) • *atenolol (Tenormin) • Non-selective Beta-1 and Beta-2 • *propranolol (Inderal) • *nadolol (Corgard) • pindolol (Visken) • carteolol (Cartrol ) • *sotalol (Betapace) • Timolol (Blocadren/Timoptic ) • penbutolol (Levatol) * Most commonly used

47. Beta Adrenergic Blocking Agents • Treatment of Glaucoma • Decrease IOP by decreasing production of aqueous humor • betaxolol (Betoptic) • timololmaleate (Timoptic) • levobunolol HCL (Betagan) • Can cause systemic side effects

48. Beta Adrenergic Blocking Agents • Side Effects • Hypotension • Bradycardia • Dizziness • Insomnia • Wheezing and Bronchospasm

49. Beta Adrenergic Blocking Agents • Nursing Measures • Never give with antacid • Check apical pulse for one minute before administering • Closely monitor blood glucose in diabetic pt. • Teach pt. to not discontinue abruptly

50. ParasympathomimeticsAKACholinergics