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DRUGS AFFECTING THE AUTONOMIC NERVOUS
SYSTEM
1
05/03/23Winter 20132Nicotinic - skeletalMuscarinic - organ
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Winter 20134
Peripheral Nervous System
Somatic: VoluntaryInnervates skeletal musclesControlled through conscious thought
NeurotransmitterAcetylcholine
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Autonomic Nervous SystemAutonomic or visceral division –
not controlled by consciousControls
• Blood pressure• Heart rate• Gastrointestinal activity• Glandular secretions
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SUBDIVISIONS OF THE AUTONOMIC NERVOUS SYSTEM
Sympathetic nervous system Fight or Flight Useful in highly stressful or emergency
situations Parasympathetic nervous system
Maintains homeostasis Works in “opposition” of the Sympathetic
nervous system “Rest and Digest”
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VOCABULARY“SYNONYMOUS” TERMS
SYMPATHETIC AKA ADRENERGIC SYMPATHOMEMETIC
• MIMICS THE SYMPATHETIC SYSTEM
PARASYMPATHETIC AKA CHOLINERGIC PARASYMPATHOMEMETIC
• MIMICS THE PARASYMPATHETIC NERVOUS SYSTEM
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Adrenergic/SympatheticNEUROTRANSMITTERS (neurohormones)CATECHOLAMINES
Epinephrine (prototype) – secreted by Adrenal gland, direct response at nerve ending
Norepinephrine – secreted by Adrenal gland. Stored in the axon, direct response at the nerve ending
RECEPTORS / RECEPTOR SITESALPHA 1ALPHA 2BETA 1BETA 2
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RECEPTOR Responses to Stimulation
ALPHA I (located on the target cells)
Blood vessels Constriction Pupils Dilation Penis Ejaculation Uterus Contraction Sphincters Constriction
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Alpha-1 Adrenergic drugs
Isuprel (isoproterenol) Used for shock
Adrenalin (epinephrine) Cardiac arrest Anaphylactic shock
Nasal decongestants (phenylephrine – Neo-Synephrine) Pseudoephedrine (Sudafed)
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RECEPTOR Responses to Stimulation
ALPHA 2 (located on presynaptic terminal) Control the release of norepinephrine and
provide the negative feedback inhibition.
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ALPHA 2 Adrenergic Drugs
CLONIDINE (Catepres) Decrease blood pressure Management of Opioid withdrawal
METHYLDOPA Decrease blood pressure, especially use din
pregnant lady to decrease BP.
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RECEPTOR Responses to Stimulation
DOPAMINE RECEPTORS
Located in various tissues and organs Cause dilation of renal, mesenteric, coronary
and cerebral arteries
D1, D2, D3, D4
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Adrenergic drugs (Alpha 1) ADVERSE EFFECTS V.
THERAPEUTIC EFFECTS
Increased HR (tachycardia) Increased Blood pressure Decreased Gastric motility…constipation Restlessness, irritability, anxiety, pallor Increased Alertness
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Adrenergic blocking drugs Alpha and BETA blocking drugs
Uses (Beta1 receptors are located primarily on cardiac tissues - cardioselective)
• Cardiac dysrhythmias• Angina• Hypertension• Congestive heart failure• Prostate hypertrophy (alpha blocker)
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Adrenergic (beta-1) blocking drugs
Beta-adrenergic blocking drugs(A-M are selective, From N-Z are non-selective )
Propranolol (Inderal)………B1, B2Nadolol (Corgard)….B1, B2Atenolol (Tenormin)….B1Metoprolol……B1Timolol (Timoptic)….B1, B2Labetalol……….Alpha and Beta
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ADRENERGIC BLOCKING DRUGS
Adverse reactions
Drowsiness, fatigueBradycardiaHypotensionOrthostatic hypotensionDiarrhea
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Adrenergic blocking drugs
Nursing considerationsPatient teaching
• Postural hypotension• Signs and symptoms of Heart
Failure• Monitor blood pressure• Taking their own pulse
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Parasympathetic (Cholinergic)Nervous
System
NEUROTRANSMITTER (neurohormone)
• Acetylcholine – Produced and stored in nerve endings
• Acetylcholine (ACh) binds to Cholinergic receptor sites and causes a response
Stimulation results in “rest and digest’
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Acetylcholinesterase(aka:cholinesterase)
Breaks down Acetylcholine or limits
response
Maintains the balance between
acetylcholine and dopamine
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Uses – only four for cholinergic drugs:Drugs that increase Acetylcholine in
the Synapse
Glaucoma – Reduce intraocular pressure
Myasthenia gravis – Disease caused by the lack of ACh at the synapse
Relief of urinary retention
Increase GI motility
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Indirect acting Cholinergic drugs
Neostigmine (Prostigmine) (anticholinesterase) prototype
• Primarily used to treat Myasthenia Gravis
Pyridostimine (Mestinon) • Myasthenia Gravis
Donepezil (Aricept) • Works in the CNS to inhibit synthesis of
Acetylcholinesterase• Used to treat Alzheimer’s disease
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Cholinergic drugs
Direct acting Cholinergic drugs
Directly stimulates the nerve ending to secrete acetylcholine
Bethanechol (Urecholine)• Used to treat urinary retention
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ADVERSE REACTIONS CHOLINERGIC DRUGS
Bradycardia Hypotension Headache, dizziness Increased secretions Abdominal cramping Increased respiratory secretions and possibly
bronchospasms
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Anticholinergic Medication
Competitive antagonists Compete with ACh Inhibit nerve transmission
Sites of action All systems except musculo-skeletal
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Anticholinergic Medication
EXAMPLES Bentyl (dicyclomine HCL)
• Antispasmotic used to decrease intestinal cramping in IBS
Atropine (Prototype)
• Acetylcholine antagonist• Antidysrhythmic• Antispasmotic• Antisecretory
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Anticholinergic Medication
USES Dry oral secretions Increase heart rate Treat ureteral colic Decrease GI motility Parkinson’s disease Decrease upper respiratory secretions
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Urinary antispasmodics AKA anticholinergics
OXYBUTYNIN (DITROPAN)• Synthetic antimuscarinic
INCREASES BLADDER CAPACITY DECREASES FREQUENCY OF VOIDING
TOLTERODINE (DETROL, DETROL LA)• Synthetic antimuscarinic
DELAYS THE URGE TO VOID INHIBITS BLADDER CONTRACTIONS
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Anticholinergic Medication
Adverse reactions / Side effects Dry mouth Blurred vision Photophobia Urinary retention Constipation Tachycardia Drowsiness
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Nursing Interventions Monitor for signs of anticholinergic crisis Report changes in heart rate, blood pressure,
or development of dysrhythmias Provide comfort measures for dryness of
mucous membranes Minimize exposure to heat or cold or strenuous
exercise Monitor I&O Monitor patient for abdominal distension, and
auscultate for bowel sounds
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Anticholinergic Crisis
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