Autonomic Nervous System
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Sympathetic (Adrenergic)
Parasympathetic (Cholinergic)
Have a balancing effect
Neurotransmitters
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Acetycholine (ACH)
Norepinephrine (NE)
Epinephrine
Dopamine
Receptors
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Alpha 1 & 2
Beta 1 & 2
Muscarinic
Nicotinie
Sympathetic Response
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Increase HR
Increase RR
Increase metabolic rate
Increase fat & glycogen breakdown
Pupillary dilation
Smooth muscle vasoconstriction
Skeletal & cardiac muscle vasodilation
Decrease GI activity
Bronchial relaxation
Parasympathetic Response
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Decrease HR
Decrease RR
Increase digestion & elimination
Increase GI tone
Bronchial constriction
Pupillary constriction
Cholinergic Agonist
(Direct Acting)
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Stimulates cholinergic receptors
bethanechol chloride (Duvoid, Urecholine)
* decreases urinary retention
*antidote is atropine
pilocarpine (Pilocar)
* increases outflow aqueous humor (open
angle glaucoma)
* pupillary constriction (miosis) & decrease
visual acuity
*headache
Nicotine
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Stimulates nicotine receptors
Used for cessation of tobacco smoking
Cannot smoke when using patch
Antichoinesterase (Indirectacting Cholinergic Agonists
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Inhibits enzyme acetlycholinesterase
Results in decrease destruction of ACH
Which results in increase cholinergic
action
Neostigmine (prostigmin)
Cholinergic Blockers
(anticholergic)
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Interrupts parasympathetic nerve
impulses
Relaxes GI & urinary tract muscles &
decrease GI secretions
Counteracts bronchospasm & decrease
respiratory secretions
Decrease salivation
Blocks cardiac vagal inhibitions
Atropine
(cholinergic antagonist)
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Blocks actions of ACH at muscarinic receptors
blocks vagal effects of SA node (tx
bradycardia)
preoperative - decrease salivation &
respiratory tract secretions
bronchodilator
watch for tachycardia, urinary retention,
constipation, dry mouth
Scopolamine
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Produces CNS depression with sedative
& tranquilizing effects
Used to tx motion sickness
Anticholinergic Overdose
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“mad as a hatter (CNS psychotic effect),
dry as a bone (salivary), red as a bat
(peripheral vasodilation), & blind as a
bat (mydriasis)
Adrenergic Receptors
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Alpha-1 & alpha-2 are differentiated by location on
nerve, alpha -1 causes vasoconstriction
Beta - 1 primarily located in heart, causes cardiac
stimulation
Beta - 2 located in smooth muscle of bronchioles,
arterioles and visceral organs, relaxation of
bronchial & GI
Side effects - alpha & beta may have headache,
insomnia, restlessness, tachycardia, hypertension,
N&V
Summary with receptors
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Alpha - 1 = vasoconstriction
beta - 1 = cardiac stimulation
beta - 2 = bronchiole dilation
Alpha-1 Adrenergic Agonist
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Phenylephrine: most common use is as
decongestant, treat nasal congestion
Side effects: sleep disturbances,
headache
Epinephrine (nonselective)
(Adrenergic Agonist)
Increases heart rate & CO
 Increase in blood sugar
 Bronchiole dilation
 Indicated for anaphylaxis,
cardiac arrest, asthma
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Beta Adrenergic Agonist
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Isoproterenal (Isuprel)
Increase contractility & heart rate
Bronchodilator
Indicated in asthma, bradycardia,
cardiac arrest
Dopamine (Intropin)
Dobutamine (Dobutrex)
Proventil & Brethine, respiratory,
bronchodilators
Alpha Adrenergic Antagonist
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Disrupts sympathetic response
Relaxation of vascular smooth muscle,
peripheral vasodilation & decrease BP
prazosin (Minipress)
Used for hypertension, angina,
peripheral vascular disorders
Watch for orthostatic hypotension
Beta Adrenergic
Blockers (antagonist)
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Prevents SNS stimulation
decrease peripheral vascular resistance,
decrease BP, decrease CO, decrease HR
Used to tx hypertension, angina,
arrhythmias
Beta Blockers
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Need to know whether cardioselective
or nonselective
Beta - 1 blockers will decrease
myocardial contractility& HR, Lopressor
(metoprolol) & Tenormin (atenolol)
Nonselective - blocks beta - 1 and beta
-2 which causes above & bronchiole
constriction
Propranolol (Inderal)
Nonselective Beta Blocker
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Important to ask if history of asthma,
bronchitis, etc.
Decrease HR so must check rate prior
to giving
client may experience decrease libido or
impotence
watch for orthostatic hypotension
Combined blocker
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Carvedilol (Coreg)
Combined alpha and beta blocker
Frequently administered with other
antihypertensive agents.
Watch for orthostatic hypotension &
bradycardia