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