Transcript Autonomic Nervous System

Autonomic Nervous System
Chapter 16, 17, 18, 19, 20
Clinical Drug Therapy
Nervous System
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Two main divisions
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Central Nervous System or CNS
Peripheral Nervous System or PNS
Central Nervous System or CNS
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Brain and spinal cord: receives and
processes incoming sensory information and
responds by sending out signals that initiate
or modify a process.
Peripheral Nervous System or PNS
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Includes all the neurons and ganglia found
outside the CNS
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Afferent (sensory): modify motor output
Efferent:
Afferent Neurons
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Afferent neurons carry sensory input from the
periphery to the CNS and modify motor
output through the reflex arc.
Efferent Neurons
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Efferent neurons carry motor signals from the
CNS to the peripheral areas of the body.
ANS / SNS
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Autonomic nervous system controls
involuntary activities of smooth muscle,
secretory glands and the visceral organs of
the body such as the heart (involuntary
activities of smooth muscle)
Somatic nervous system innervates the
skeletal muscles and controls voluntary
movement
Autonomic Nervous System
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Sympathetic Nervous System
Para sympathetic System
Enteric System
The Race Horse and the Cow
Sympathetic Nervous System
Sympathetic System
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Fight or Flight – stimulated by physical or
emotional stress (exercise or work), pain,
hemorrhage, intense emotions, temperature
extremes
Sympathetic Nervous System
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Protective mechanisms designed to help
person cope with the stress or get away from
it.
Neurotransmitters
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Neurotransmitters
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Acetylcholine: skeletal muscle
Norepinepherine: stress response
Norepinephrine and epinephrine
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Both always present in the blood.
Norepinephrine varies according to the
amount of stress present and will cause
transient changes in heart rate and systemic
arteries and veins.
Epinephrine is a constant in regulating heart
rate, vasoconstriction in systemic arteries and
veins and vasodilation of muscles and liver.
Dopamine
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Adrenergic neurotransmitter – essential for
normal brain function.
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Studies focus on connection between dopamine
malfunction in schizophrenia and Parkinson’s
Disease.
Role of dopamine in drug addition to drugs:
stimulants and depressants.
Protective Mechanisms
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Intensity of response depends on
Norepinephrine and epinephrine
Fight or flight
Body Responses
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Increase in blood pressure and cardiac
output.
Increase blood flow to brain, heart and
skeletal muscles.
Decrease blood flow to skin and organs not
needed for “flight”.
Increase in glycogen for energy, mental
activity, muscle strength, blood coagulation,
respiratory rate, pupil dilation to aid vision,
and increase in sweating.
Fight of Flight Response
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Can be a problem if the body stay in the “fight
or flight” mode.
Type A personalities?
High stress environment?
Medications may be needed reduce the
physiologic body responses.
Parasympathetic Nervous System
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Rest and Digest
Save energy
Decreased heart rate
Adrenergic Receptors
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Norepinephrine and epinephrine interact with
two adrenergic receptors
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Alpha and beta
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Alpha 1
Alpha 2
Beta 1
Beta 2
Alpha 1
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Alpha 1 receptors allows calcium ions to
move into the cell and produce muscle
contraction.
Alpha 1
Location
 Blood vessels
 Kidney
 Intestinal smooth muscles
 Genitourinary
 Eyes = blinking
 Pregnant uterus =
contractions
 Male sexual organs =
sexual function
Effects of stimulation
 Vasoconstriction
 Release of renin (kidney)
 Relaxation
Alpha 2
Location
 Nerve endings
 Vascular smooth
muscles
 Pancreatic beta cells
 Platelets
Effects of stimulation
 Inhibits release of
Norepinephrine
 Vasoconstriction
 Inhibit insulin secretion
 Aggregation or clotting
Beta 1
Location
 Heart
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Kidneys
Effects of stimulation
 Increase heart rate,
force of contraction,
automaticity and rate of
atrial-ventricular
function
 Increased renin release
Beta 2
Location
 Bronchioles
 Blood vessels
 Gastrointestinal tract
 Liver
 Urinary bladder
 Pregnant uterus
Effects of stimulation
 Vasodilation
 Decreased motility and
tone
 Glycogenolysis
 Relaxed detrusor
muscle (bladder
muscle)
 Relaxation of uterus
Dopamine
Location
 Blood vessels of
kidney, heart, and other
viscera
Effects of stimulation
 Vasodilation
Parasympathetic Nervous System
Functions stimulated by PNS: Resting,
reparative, or vegetative function
Body Responses
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Dilation of blood vessels in skin
Decrease heart rate (bradycardia)
Increase secretion of digestive enzymes
Constriction of smooth muscle of bronchi
Increase in sweat glands
Contraction of smooth muscles of urinary
bladder
Contraction of smooth muscle of skeletal
system
Neurotransmitter
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Acetylcholine
Two types of cholinergic receptors
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Nicotinic: located in motor nerves and skeletal
muscles
Muscarinic: located in internal organs,
cardiovascular, respiratory, GI and GU
Autonomic Drugs
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Drugs used due to their ability to stimulate or
block activity of the sympathetic or
parasympathetic nervous system.
Effect of Drugs
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Drugs that act of ANS usually affect the entire
body.
Effects depend on whether you are trying to
stimulate or inhibit function.
Receptor Activity
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Drugs are developed to stimulate or inhibit
particular subtypes of receptors.
More selective on particular body tissues.
Decrease adverse effects on other body
tissues – side effects.
Simulation of SNS
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Stimulation of sympathetic nervous system
can be divided into drug classifications:
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Adrenergic
Sympathomimetic
Alpha and beta adrenergic agonists
Agonist
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In pharmacology an agonist is a substance
that binds to a specific receptor and triggers a
response in the cell.
Blockage of SNS
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Drugs that inhibit sympathetic nervous
system are classified as
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Antiadrenergic
Sympatholytic anticholinergic
Stimulation of PNS
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Parasympathetic nervous system stimulation
drug classifications
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Cholinergic
Parasympathomimenic
Cholinomimetic
Blocking of PNS
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Drugs that inhibit parasympathetic stimulation
are classified as:
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Anticholinergic
Parasympatholytic
Cholenergic blocking drugs
Classifications: SNS
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Sympathetic nervous system drug
classifications
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Adrenergic - stimulating
Antiadrenergic - blocking
Classifications: PNS
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Parasympathetic
nervous system drugs
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Cholinergic
Anticholinergic
Adrenergic Drugs
Chapter 17
Adrenergic Drugs
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What do they do?
Stimulation of the sympathetic nervous
system.
Mechanism of Action
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Three mechanisms:
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Directly with alpha 1 or beta-adrenergic receptors
on surface membrane.
Indirect effects of postsynaptic adrenergic
receptors.
Mixed action – combination of action on direct and
indirect receptor.
Heart
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Direct stimulation of receptors
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Alpha 1 - Vasoconstriction of blood vessels which
increases blood pressure – pressor or
vasopressor effect.
Beta 2 - increased force of myocardial contraction
- Increased speed of electrical conduction in the
heart.
Lungs
Asthma and COPD (Chronic Obstructive
Pulmonary Disease): Beta 2 drugs or
bronchodilators are used to relieve bronchoconstriction and broncho-spasm.
Pregnancy
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Adrenergic drugs used to relax uterine
muscles in preterm labor.
OTC Adrenergic Drugs
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Common cold: anti-histamines
Allergy: nasal or oral to relieve nasal
congestion
Adrenergic Drugs
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Epinephrine
Pseudoephedrine – Sudafed
Isoproterenol (Isuprel)
Phenylephrine (Neo-Synephrine)
Clonidine (antihypertensive)
How does one choose a drug?
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How emergent is the situation
PO or IM or IV
Allergic Response
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Runny nose, itchy eyes, cough
Asthma: Cough with bronchospasms,
difficulty breathing or SOB (shortness of
breath)
Anaphylactic shock – edema of airway
Allergy Response
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Nasal congestion, itchy eyes, non-productive
cough
Seasonal response to environmental causes
Commonly mixed with other drugs in cold
medications
Pseudoephedrine
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Therapeutic classification: allergy, cold, and cough
remedies, nasal drying, and decongestants.
Indications: symptomatic management of nasal
congestion associated with acute viral upper
respiratory tract infection. Most often used in
combination with other drugs.
Action: stimulates Alpha and beta-adrenergic
receptors – vasoconstriction in respiratory tract
mucosa – possible bronchodilation
Therapeutic effects: reduction of nasal congestion,
and swelling of nasal passages.
Forms and Dosage
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How supplied: tabs, chew tabs, extended
release tabs, liquid or drops
Dosing: 30 to 60 mg / dose q 6-8 hours PO
Maximum dose 240 mg/24 hours
Sustained release: 120 mg PO q 12 hours
Contraindications
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Severe Hypertension
Severe CAD / coronary artery disease
Use with caution in pregnancy, breast feeding
and renal failure
Use with caution!
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Mild or moderate hypertension,
hyperglycemia, hyperthyroidism, and cardiac
disease.
Side Effects
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Dizziness, nervousness, restlessness,
insomnia and arrhythmias
Seizures
Cardiovascular collapse
Additional Information
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OTC used in combination with antihistamines
Primarily excreted renally – adjust in patients
with renal impairment
May cause false-positive for amphetamines –
athletes
Currently need to ask pharmacist for Sudafed
– OTC has been limited due to abuse
Nursing Implications
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Assess for congestion
Monitor pulse and blood pressure before
beginning therapy
Assess lung sound for signs of bronchial
secretions
Severe Anaphylactic Shock
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Usually involving the airways
Some thing as simple as food allergy can
trigger it
Peanuts, shell fish, legumes, bee sting,
medications
Symptoms usually starts with numbness and
tingling of lips and leads to swelling of the
glottis or epiglottis – this can result in closure
of the airway.
How Do You Treat It?
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Epinephrine would be the drug of choice
Classification: adrenergic
Action: affects both the beta (cardiac) and
beta (pulmonary) receptors – produces
bronchodilation – inhibits hypersensitivity
reaction of mast cells.
Epinephrine
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Therapeutic Effects:
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Bronchodilation
Maintenance of heart rate and blood pressure
Adverse Side Effects:
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Nervousness, restlessness, tremors, angina,
arrhythmias, hypertension, tachycardia
How it is given?
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Sub-Q or IV or inhaled
The subcutaneous or intramuscular
administration will help it to get into the blood
stream quicker – epi-pen is given to clients
with severe allergy reactions
Not given by mouth because drug is
inactivated by gastric juices
Can be inhaled in asthma attack
CAUTION!
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Check dose, concentration, and route of
administration – fatalities have occurred from
medication errors – us TB syringe for
subcutaneous administration
Inhaled provided as metered dose inhaler
160 to 250 mcg – broncho-constriction is
asthma
IV would be 0.1 to 0.25 mg (cardiopulmonary
resuscitation)
Precautions with Use
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Tachyarrhythmia's (fast irregular heart rate),
headache, nausea, and palpitations
Short acting so more definitive treatment
needs to be initiated
Need cardio-respiratory monitoring
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Pulse oximetry
Cardiac monitor
Cardiac Arrest
Epinephrine is the best studied and most
widely administered adrenergic agonist used
for the treatment of cardiac arrest.
Used to jump start the heart.
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Vasopressor / Inotropic Drugs
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Used extensively along with Dopamine to
maintain myocardial and cerebral perfusion
post cardiac arrest.
Administered in small, consistent amounts
intravenous.
Antiadrenergic Drugs
Chapter 18
Clinical Drug Therapy
Antiadrenergic Drugs
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Blocks the effects of the sympathetic nerve
stimulation, endogenous catecholamine and
adrenergic drugs.
Mechanism of Action
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Act on alpha or beta receptors
Receptors are blocked by adrenergic
antagonists or pre-synaptic alpha 2 receptors
are stimulated.
When Used?
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To manage hypertension and a number of
cardiovascular disorders.
Anti – hypertensive Medication
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Clonidine: Catapres, Catapres TTS, Dixarit,
Duracion
Pharmacologic classification: adrenergic
(centrally acting)
Therapeutic classification: antihypertensive
Clonidine
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Action: Stimulates the alpha-adrenergic
receptors in the CNS which results in
decreased sympathetic outflow inhibiting
cardioacceleration and vasoconstriction
centers. Prevents pain signal transmission to
the CNS by stimulating alpha-adrenergic
receptors in the spinal cord.
Therapeutic Effects: decreased blood
pressure. Decreased pain.
Cholinergic Drugs
Chapter 19
Clinical Drug Therapy
Cholinergic Drugs
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Cholinergic drugs stimulate the
parasympathetic nervous system.
Mechanism of Action
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Direct acting cholinergic drugs are synthetic
derivative of choline.
Effects of drug
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Decrease heart rate, vasodilation, and changes in
BP
Increase tone and contractibility of smooth muscle
Increase tone and contractibility of bronchial
smooth muscles
Increased respiratory secretions
Indications for Use
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Urinary retention without obstruction
Postoperative abdominal distention due to
paralytic ileus
Myasthenia gravis – muscle weakness
During surgery to reverse the effects of
muscle relaxants used during surgery
Nursing Assessment: urine retention
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Urinary retention
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Bladder distention
Fluid intake
Time of last void
How do you know drug is working?
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Fluid intake equal to urine output
Patient has voided within the last 8 hours
Nursing Assessment: paralytic ileus
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Paralytic ileus
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Hypo-peristalsis
Decreased bowel sounds
No gas or bowel movement
How do you know drug is working?
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Bowel sounds heart in all four quadrants
Client states has passes gas
Client states has had a bowel movement
Nursing Assessment: Myasthenia Gravis
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Signs and symptoms: muscle weakness,
ptosis (droopy eye lid), diplopia (double
vision), difficulty chewing and swallowing,
decreased activity intolerance.
How do you know medication is working?
Increased muscle tone, no droopy eye lid or
double vision, increased activity tolerance.
Nursing Assessment: Alzheimer
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Signs and symptoms: loss of memory,
cognitive function and decreased self-care
Signs medication is working: increase
memory and cognitive function and increase
interest in activities of daily living
Use in Older Adults
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May be used in myasthenia gravis or
Alzheimer’s disease
Contraindications
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Renal obstruction
Liver disease
Anticholinergic Drugs
Chapter 20
Clinical Drug Therapy
Anticholinergic Drugs
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Anticholinergics are a class of medications
that inhibit parasympathetic nerve impulses
by selectively blocking the binding of the
neurotransmitter acetylcholine to its receptor
in nerve cells.
Mechanism of Action
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Drugs act by occupying receptor sites on
target organs innervated by parasympathetic
nervous system leaving fewer receptor sites
free to respond to acetylcholine.
Parasympathetic response is absent or
decreased depending on number of receptors
blocked.
Effects of Anticholinergic Drugs
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CNS stimulation followed by depression
Decreased cardiovascular response to
parasympathetic (vagal) stimulation that
slows heart rate
Bronchodilation and decrease respiratory
secretions
Antispasmodic effects in GI system
Change in intra-ocular pressure in patients
with glaucoma
Uses
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GI disorders – peptic ulcer disease, gastritis,
increased gastric acid secretion – relax gastric
smooth muscle (replaced by newer drugs)
Genitourinary – anti-spasmodic – urgency
Excessive secretions
Ophthalmology – relax eye for exam
Respiratory disorder – asthma or bronchitis –
inhaled form only
Cardiac disorders – bradycardia or heart block
Parkinson’s disease
Side Effects
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Hyperthermia, hot, dry flushed skin, dry
mouth, tachycardia, delirium, paralytic ileus
and urinary retention
Atropine
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Pharmacological classification:
anticholinergic
Therapeutic classification: antiarrhythmic
Action: Inhibits the action of acetylcholine at
postganglionic sites located in the smooth
muscle, secretory glands, CNS. Low doses
decrease: sweating, salivation and
respiratory secretions.
Atropine
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Therapeutic effects:
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Increased heart rate
Decreased GI and respiratory secretions
Reversal of muscarinic effects
May have spasmodic action on the biliary and
genitourinary tracts.
Atropine
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Side effects: drowsiness, blurred vision,
tachycardia, dry mouth, urinary hesitancy.
Atropine
Prototype of anticholineric drugs – atropine
sulfate
Therapeutic
Previously used in preoperative patients to
reduce secretions – other newer drugs have
replaced