Pharmacology for the Dental Hygienist

1. Pharmacology for the Dental Hygienist Drugs Affecting the ANS

2. Chapter 4 Autonomic Drugs

3. Autonomic nervous system (ANS) • Regulates: • Blood pressure • Heart rate • GI tract motility • Salivary gland secretion • Bronchial smooth muscle

4. ANS Anatomy • 2 divisions: • PANS • Parasympathetic • SANS • Sympathetic

5. ANS Anatomy Cont. • Both the PANS and SANS have: • Afferent fibers • Sensory • Central integrating areas • Coordinating information • Efferent (peripheral) fibers • Motor pre-ganglionic • Motor post-ganglionic

6. Efferent Nerves • Figure 4-1 • Pre-ganglionic neuron originates in the CNS • Pre-ganglionicneuron – synapses with post-ganglionicneuron • Post-ganglionic neuron innervates the organ or tissue • Length of pre-ganglionic neurons varies • Length and number of post-ganglionic neurons varies • Neurotransmitters allow information to pass from 1 neuron to another

7. Synaptic Junction

8. PANS • Parasympathetic Nervous System • Relaxation response • Nerves come from cranial and sacral regions of the CNS • Long pre-ganglionic nerves • Short & few post-ganlionic nerves • Discrete effect

9. SANS • Sympathetic Nervous System • Fight or flight response • Nerves come from thoracic and lumbar regions of the CNS • Short pre-ganglionic nerves • Long & many post-ganlionic nerves • Diffuse effect

10. SANS- Adrenal Medulla • The adrenal gland is innervated by the SANS • Releases epinephrine (E) • Aids in the “fight or flight” response

11. PANS vs. SANS • Act in opposite directions • See Table 4-1 • PANS • Conservation • Digestion • SANS • To cope with sudden emergencies

12. Neurotransmitters of the ANS • Function: carry messages • Acetylcholine (Ach) • Norepinephrine (Ne) • Epinephrine (E)

13. Acetylcholine (Ach) • Between pre- and post-ganglionic nerves in both the PANS and SANS • Nerves that release Ach: • Cholinergic • Also termed nicotinic • Responds to nicotine

14. Post-ganglionic Nerves to Tissue • PANS • Ach • Cholinergic • Muscarinic • Responds to muscarine • SANS • Ne (or E from adrenal medulla) • Adrenergic

15. ANS • Red arrows – PANS • Brown arrow – SANS • Neurotransmitters • Pre-ganglionic • Acetylcholine (Ach) • PANS post-ganglionic • Acetylcholine (Ach) • SANS post-ganglionic • Norepinephrine (Ne) • From adrenal gland – epinephrine (E)

16. Review: • In the PANS, only Ach is released • One cholinergic (nicotinic) receptor • One muscarinic receptor • In the SANS, Ach is released as well as Ne/ E • One cholinergic (nicotinic) receptor • One adrenergic receptor

17. Inactivating Neurotransmitters • Acetylcholine • Cholinesteraseis the enzyme that breaks down Ach in the synapse (hydrolysis) • Norepinephrine • Is usually taken back up into the neuron that secreted it (re-uptake) • Ne/ E – • COMT- enzyme found in the liver breaks down some epinephrine & NE • Monoamine oxidase (MAO) - enzyme breaks down excess Ne and E inside the neuron

18. Match Neurotransmitters to Sites • PANS • Pre to post • Post to organ • SANS • Pre to post • Post to organ • Adrenal gland • Acetylcholine (Ach) • Norepinephrine (Ne) • Epinephrine (E)

19. Video • You Tube- The ANS • https://www.youtube.com/watch?v=x4PPZCLnVkA

20. Drugs that affect the ANS • Can affect either the PANS or SANS • Can cause stimulation or block stimulation • P+ • P- • S+ • S-

21. Naming Drugs • Prefix • Parasympatho- affecting the PANS • Sympatho - affecting the SANS • Suffix • -mimetic mimics that division of the ANS (agonist) • -lytic blocks that division of the ANS (antagonist)

22. Review: • What would a sympatholytic drug do? • Block the SANS response • What would a parasympathomimetic do? • Stimulate the PANS

23. PANS Drugs • PANS Agonist • Causes effect • Ach • Cholinergic • pilocarpine • neostigmine • PANS Antagonist • Block the action of Ach • Anticholinergic • atropine • scopolamine

24. SANS Drugs • SANS Agonist • Cause effect • Ne or E • Adrenergic • Alpha and beta receptors • epinephrine • ephedrine • dopamine • Ritalin • SANS Antagonist • Block action of Ne or E • Adrenergic blocker • atenolol • nadolol • propranolol • timolol

25. Functions of the ANS

26. Functions of the ANS table 4-1 PANS SANS • eye – miosis, constriction & lacrimation • heart – decrease force & rate • arteries – dilation • respiratory – bronchoconstriction • pancreas – secretion • urinarysphincter – relaxation • GI – increase activity • salivation – increased • eye – mydriasis, dilation • heart – increase force & rate • arteries – constriction • respiratory – bronchodilation • pancreas – decreased secretion • urinarysphincter – constriction • GI activity – decreased • saliva - decreased

27. Drug Action Direct Indirect • Acts directly on the receptor/ neurotransmitter • Stimulates the PANS or SANS • Enzyme inhibitors • Enzyme that normally destroys the neurotransmitter is inhibited- leads to build up of the neurotransmitter resulting in PANS/ SANS stimulation

28. Pharmacologic Effects of Cholinergic Drugs • Increases • GI motility • Acid • Secretions • Salivation • Urination • If indirect – heart rate & output • Decreases • BP • Intraocular pressure • If direct – heart rate & output

29. Adverse Reactions to Cholinergic Drugs • Extension of pharmacological effects • Large doses • SLUD • Salivation • Lacrimation • Urination • Defecation • Includes diarrhea, cramping

30. Contraindications of Cholinergic Drugs • bronchial asthma • May cause bronchospasms and asthma attack • GI or urinary obstruction • Could cause system to “back up” • peptic ulcer • Could cause it to become worse

31. Uses of Cholinergic Drugs • Direct acting: • Treatment of glaucoma • Urinary retention • Xerostomia • Indirect acting: • Treatment of glaucoma

32. Cholinergic Drugs of Importance • Pilocarpine (Salagen) • Dental use: treatment of xerostomia • Neostigmine • Medical use: treatment of glaucoma and myasthenia gravis

33. Board Question • A patient complains of dry mouth. This condition might be caused by any of the following EXCEPT: a. codeine. b. atropine. c. pilocarpine. d. dextroamphetamine (dexedrine).

34. Pharmacologic Effects of AnticholinericDrugs • Dilate pupil & blur near vision • Bronchodilation • Increase • Heart rate- (direct) • Decrease • Secretion of exocrine glands • Motility of GI tract • Heart rate- (indirect)

35. Adverse Reactions to Anticholinergic Drugs • Extensions of pharmacologic effects • Xerostomia-dry mouth • blurred vision • Photophobia • Tachycardia • Fever • Flushed skin • Urinary retention • Constipation

36. Contraindications of Anticholinergic Drugs • Glaucoma • Cause increase in intraocular pressure • prostatic hypertrophy • Causes even greater trouble urinating • GI & urinary obstruction • Causes constipation • CV disease • Possibility of blocking vagus nerve

37. Uses of Anticholinergic Drugs • Pre-op medication • Decreases saliva/ mucous, keeps heart rate up when under general anesthesia • Gastric ulcers • Diarrhea • Eye exam • Dilation so eye can be examined • Tremors • Parkinson’s disease • Motion sickness • CNS depressant

38. Drug Interactions- Anticholinergic Drugs • Do not use with: • Antihistamines • tricyclic antidepressants

39. Anticholinergic Drugs of Importance • Atropine • Dental use: to produce a dry field • Medical use: eye examination • Scopolamine • Medical use: prevent motion sickness

40. Adrenergic Receptors

41. Pharmacologic Effects of Adrenergic Drugs • CNS – alert • Mydriasis • Relax bronchioles (B2) • Reduced salivary flow • Increased (B1) • Heart rate & force • Blood pressure

42. Adverse Reactions of Adrenergic Drugs • Extension of pharmacological effect • Anxiety • Tremors • Heart palpations • Increased blood pressure

43. Contraindications of Adrenergic Drugs • Patients with angina pectoris • Hypertension • Hyperthroidism

44. Uses of Adrenergic Drugs • Treatment of anaphylaxis • Asthma • Shock • Cardiac arrest • Added to LA to prolong action • Hemostasis- retraction cord • Decognestant • CNS stimulant- ADD • Narcolepsy

45. Adrenergic Drugs of Importance • Epinephrine • Medical uses: acute asthma attack, treating anaphylaxis • Dental uses: as a vasoconstrictor in LA • Dopamine • Medical uses: shock and congestive heart failure • Ephedrine • Medical uses: decongestant and chronic asthma • Ritalin • Medical uses: CNS stimulant for ADD/ ADHD

46. Pharmacologic Effects of Adrenergic Blocking Drugs • Αlpha blockers – decrease vascular spasms • Βeta blockers – decrease blood pressure • Drug name ends in -olol • Both – decrease blood pressure • Drug name ends in -alol

47. Uses of Adrenergic Blockers • Treating hypertension • Raynaud’s syndrome • Cardiac arrthymias • Angina pectoris • Migraines

48. Adrenergic Blockers of importance • Atenolol • Hypertension • Nadolol • Hypertension • Propanolol • Hypertension • Glaucoma • Migraines • Angina • Timolol • Hypertension • Glaucoma

49. Video • You Tube- ANS Drugs • https://www.youtube.com/watch?v=cbNMuUP71RY

50. Board Question • All of the following are indications for the use of epinephrine EXCEPT: a. a nervous patient. b. an acute asthma attack. c. an allergic reaction. d. to provide hemostatis.