Download - Pharmacology for the Dental Hygienist
PHARMACOLOGY FOR THE DENTAL HYGIENIST
Drugs Affecting the ANS
CHAPTER 4
Autonomic Drugs
AUTONOMIC NERVOUS SYSTEM (ANS)
Regulates: Blood pressure Heart rate GI tract motility Salivary gland secretion Bronchial smooth muscle
ANS ANATOMY 2 divisions:
PANS Parasympathetic
SANS Sympathetic
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
EFFERENT NERVES
Figure 4-1 Pre-ganglionic neuron originates in the CNS Pre-ganglionic neuron – synapses with post-
ganglionic neuron Post-ganglionic neuron innervates the organ
or tissueLength of pre-ganglionic neurons variesLength and number of post-ganglionic
neurons varies Neurotransmitters allow information to
pass from 1 neuron to another
SYNAPTIC JUNCTION
PANS
Parasympathetic Nervous SystemRelaxation responseNerves come from cranial
and sacral regions of the CNS
Long pre-ganglionic nerves
Short & few post-ganlionic nerves
Discrete effect
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
SANS- ADRENAL MEDULLA
The adrenal gland is innervated by the SANS Releases epinephrine (E) Aids in the “fight or flight” response
PANS VS. SANS
Act in opposite directions See Table 4-1 PANS
Conservation Digestion
SANS To cope with sudden emergencies
NEUROTRANSMITTERS OF THE ANS
Function: carry messages
Acetylcholine (Ach)
Norepinephrine (Ne)
Epinephrine (E)
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
POST-GANGLIONIC NERVES TO TISSUE
PANS Ach Cholinergic Muscarinic
Responds to muscarine
SANS Ne (or E from adrenal medulla) Adrenergic
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)
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
INACTIVATING NEUROTRANSMITTERS
Acetylcholine Cholinesterase is
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
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)
VIDEO
You Tube- The ANS https://www.youtube.com/watch?v=x4PPZCL
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DRUGS THAT AFFECT THE ANS
Can affect either the PANS or SANS Can cause stimulation or block stimulation
P+ P- S+ S-
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)
REVIEW:
What would a sympatholytic drug do? Block the SANS response
What would a parasympathomimetic do? Stimulate the PANS
PANS DRUGS
PANS Agonist Causes effect Ach Cholinergic
pilocarpine neostigmine
PANS Antagonist Block the action of
Ach Anticholinergic
atropine scopolamine
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
FUNCTIONS OF THE ANS
FUNCTIONS OF THE ANS TABLE 4-1
eye – miosis, constriction & lacrimation
heart – decrease force & rate
arteries – dilation respiratory –
bronchoconstriction pancreas – secretion urinary sphincter –
relaxation GI – increase activity salivation – increased
eye – mydriasis, dilation heart – increase force &
rate arteries – constriction respiratory –
bronchodilation pancreas – decreased
secretion urinary sphincter –
constriction GI activity – decreased saliva - decreased
PANS SANS
DRUG ACTION
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
Direct Indirect
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
ADVERSE REACTIONS TO CHOLINERGIC DRUGS
Extension of pharmacological effects Large doses SLUD
Salivation Lacrimation Urination Defecation
Includes diarrhea, cramping
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
USES OF CHOLINERGIC DRUGS
Direct acting: Treatment of glaucoma Urinary retention Xerostomia
Indirect acting: Treatment of glaucoma
CHOLINERGIC DRUGS OF IMPORTANCE
Pilocarpine (Salagen) Dental use: treatment of xerostomia
Neostigmine Medical use: treatment of glaucoma and
myasthenia gravis
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).
PHARMACOLOGIC EFFECTS OF ANTICHOLINERIC DRUGS Dilate pupil & blur
near vision Bronchodilation Increase
Heart rate- (direct)
Decrease Secretion of exocrine
glands Motility of GI tract Heart rate- (indirect)
ADVERSE REACTIONS TO ANTICHOLINERGIC DRUGS
Extensions of pharmacologic effects Xerostomia-dry mouth blurred vision Photophobia Tachycardia Fever Flushed skin Urinary retention Constipation
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
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
DRUG INTERACTIONS- ANTICHOLINERGIC DRUGS
Do not use with: Antihistamines tricyclic antidepressants
ANTICHOLINERGIC DRUGS OF IMPORTANCE
Atropine Dental use: to produce a dry field Medical use: eye examination
Scopolamine Medical use: prevent motion sickness
ADRENERGIC RECEPTORSReceptor Site of Action Response
Alpha Eye (iris)Arteries in skin and skeletal muscle
MydriasisVasoconstriction (NE & EPI)
Beta1 Heart Increased force & rate of contraction
Beta2 Eye (ciliary muscle)LungsSmooth muscle in blood vessel of skeletal muscleUterus
Relaxation for distant visionBronchodilation (EPI)Relaxation causing vasodilationRelaxation
PHARMACOLOGIC EFFECTS OF ADRENERGIC DRUGS CNS – alert Mydriasis Relax bronchioles (B2) Reduced salivary flow Increased (B1)
Heart rate & force Blood pressure
ADVERSE REACTIONS OF ADRENERGIC DRUGS
Extension of pharmacological effect Anxiety Tremors Heart palpations Increased blood pressure
CONTRAINDICATIONS OF ADRENERGIC DRUGS
Patients with angina pectoris Hypertension Hyperthroidism
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
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
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
USES OF ADRENERGIC BLOCKERS
Treating hypertension Raynaud’s syndrome Cardiac arrthymias Angina pectoris Migraines
ADRENERGIC BLOCKERS OF IMPORTANCE
Atenolol Hypertension
Nadolol Hypertension
Propanolol Hypertension Glaucoma Migraines Angina
Timolol Hypertension Glaucoma
VIDEO
You Tube- ANS Drugs https://www.youtube.com/watch?v=cbNMuUP
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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.
CASE STUDY: BESS BLUE
Cholinergic agonist Frequent urination Impact on DHY treatment
Increase salivation Avoid light in eyes Monitor vital signs
Isopto-atropine is an anti-cholineric drug
SAM SALMON
Classifications Afrin – sympathomimetic or nasal decongestant Tavist 1 – antihistamine Sudafed – alpha adrenergic agonist Vancenase – corticosteroid
Effects of drugs Stimulate CNS, heart rate, dilate pupils, bronchodilation,
↓ salivation
SAM SALMON CONTINUED Oral conditions
Xerostomia Candidiasis
Considerations Rinse after using Vancenase Dry mouth
Drugs to avoid with heart disease Afrin, Sudafed, Tavist 1