Autonomic Nervous System by MikeJenny

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									Autonomic Nervous System


   Chapter 16, 17, 18, 19, 20
   Clinical Drug Therapy
Nervous System

   Two main divisions
       Central Nervous System or CNS
       Peripheral Nervous System or PNS
Central Nervous System or CNS

   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

   Includes all the neurons and ganglia found
    outside the CNS
       Afferent (sensory): modify motor output
       Efferent:
Afferent Neurons

   Afferent neurons carry sensory input from the
    periphery to the CNS and modify motor
    output through the reflex arc.
Efferent Neurons

   Efferent neurons carry motor signals from the
    CNS to the peripheral areas of the body.
ANS / SNS

   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

   Sympathetic Nervous System
   Para sympathetic System
   Enteric System
The Race Horse and the Cow




  Sympathetic Nervous System
Sympathetic System

   Fight or Flight – stimulated by physical or
    emotional stress (exercise or work), pain,
    hemorrhage, intense emotions, temperature
    extremes
Sympathetic Nervous System

   Protective mechanisms designed to help
    person cope with the stress or get away from
    it.
Neurotransmitters

   Neurotransmitters
       Acetylcholine: skeletal muscle
       Norepinepherine: stress response
Norepinephrine and epinephrine

   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

   Adrenergic neurotransmitter – essential for
    normal brain function.
       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

   Intensity of response depends on
    Norepinephrine and epinephrine
   Fight or flight
Body Responses

   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

   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

    Rest and Digest
    Save energy
    Decreased heart rate
Adrenergic Receptors

   Norepinephrine and epinephrine interact with
    two adrenergic receptors
       Alpha and beta
           Alpha 1
           Alpha 2
           Beta 1
           Beta 2
Alpha 1

   Alpha 1 receptors allows calcium ions to
    move into the cell and produce muscle
    contraction.
Alpha 1

Location                      Effects of stimulation
 Blood vessels                Vasoconstriction

 Kidney                       Release of renin (kidney)

 Intestinal smooth muscles    Relaxation

 Genitourinary

 Eyes = blinking

 Pregnant uterus =
  contractions
 Male sexual organs =
  sexual function
Alpha 2

Location                  Effects of stimulation
 Nerve endings            Inhibits release of

 Vascular smooth           Norepinephrine
  muscles                  Vasoconstriction

 Pancreatic beta cells    Inhibit insulin secretion

 Platelets                Aggregation or clotting
Beta 1

Location      Effects of stimulation
 Heart        Increase heart rate,
                force of contraction,
                automaticity and rate of
                atrial-ventricular
   Kidneys     function
               Increased renin release
Beta 2

Location                   Effects of stimulation
 Bronchioles               Vasodilation

 Blood vessels             Decreased motility and

 Gastrointestinal tract     tone
 Liver                     Glycogenolysis

 Urinary bladder           Relaxed detrusor

 Pregnant uterus
                             muscle (bladder
                             muscle)
                            Relaxation of uterus
Dopamine

Location                     Effects of stimulation
 Blood vessels of            Vasodilation
  kidney, heart, and other
  viscera
Parasympathetic Nervous System

Functions stimulated by PNS: Resting,
  reparative, or vegetative function
Body Responses

   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

   Acetylcholine
   Two types of cholinergic receptors
       Nicotinic: located in motor nerves and skeletal
        muscles
       Muscarinic: located in internal organs,
        cardiovascular, respiratory, GI and GU
Autonomic Drugs

   Drugs used due to their ability to stimulate or
    block activity of the sympathetic or
    parasympathetic nervous system.
Effect of Drugs

   Drugs that act of ANS usually affect the entire
    body.
   Effects depend on whether you are trying to
    stimulate or inhibit function.
Receptor Activity

   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

   Stimulation of sympathetic nervous system
    can be divided into drug classifications:
       Adrenergic
       Sympathomimetic
       Alpha and beta adrenergic agonists
Agonist

   In pharmacology an agonist is a substance
    that binds to a specific receptor and triggers a
    response in the cell.
Blockage of SNS

   Drugs that inhibit sympathetic nervous
    system are classified as
       Antiadrenergic
       Sympatholytic anticholinergic
Stimulation of PNS

   Parasympathetic nervous system stimulation
    drug classifications
       Cholinergic
       Parasympathomimenic
       Cholinomimetic
Blocking of PNS

   Drugs that inhibit parasympathetic stimulation
    are classified as:
       Anticholinergic
       Parasympatholytic
       Cholenergic blocking drugs
Classifications: SNS

   Sympathetic nervous system drug
    classifications
       Adrenergic - stimulating
       Antiadrenergic - blocking
Classifications: PNS

   Parasympathetic
    nervous system drugs
       Cholinergic
       Anticholinergic
Adrenergic Drugs


   Chapter 17
Adrenergic Drugs

   What do they do?
   Stimulation of the sympathetic nervous
    system.
Mechanism of Action

   Three mechanisms:
       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

   Direct stimulation of receptors
       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 broncho-
 constriction and broncho-spasm.
Pregnancy

   Adrenergic drugs used to relax uterine
    muscles in preterm labor.
OTC Adrenergic Drugs

   Common cold: anti-histamines
   Allergy: nasal or oral to relieve nasal
    congestion
Adrenergic Drugs

   Epinephrine
   Pseudoephedrine – Sudafed
   Isoproterenol (Isuprel)
   Phenylephrine (Neo-Synephrine)
   Clonidine (antihypertensive)
How does one choose a drug?

   How emergent is the situation
   PO or IM or IV
Allergic Response

   Runny nose, itchy eyes, cough
   Asthma: Cough with bronchospasms,
    difficulty breathing or SOB (shortness of
    breath)
   Anaphylactic shock – edema of airway
Allergy Response

   Nasal congestion, itchy eyes, non-productive
    cough
   Seasonal response to environmental causes
   Commonly mixed with other drugs in cold
    medications
Pseudoephedrine

   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

   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


   Severe Hypertension
   Severe CAD / coronary artery disease
   Use with caution in pregnancy, breast feeding
    and renal failure
Use with caution!

   Mild or moderate hypertension,
    hyperglycemia, hyperthyroidism, and cardiac
    disease.
Side Effects

   Dizziness, nervousness, restlessness,
    insomnia and arrhythmias
   Seizures
   Cardiovascular collapse
Additional Information

   OTC used in combination with anti-
    histamines
   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

   Assess for congestion
   Monitor pulse and blood pressure before
    beginning therapy
   Assess lung sound for signs of bronchial
    secretions
Severe Anaphylactic Shock

   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?


   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

   Therapeutic Effects:
       Bronchodilation
       Maintenance of heart rate and blood pressure


   Adverse Side Effects:
       Nervousness, restlessness, tremors, angina,
        arrhythmias, hypertension, tachycardia
How it is given?

   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!

   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

   Tachyarrhythmia's (fast irregular heart rate),
    headache, nausea, and palpitations
   Short acting so more definitive treatment
    needs to be initiated
   Need cardio-respiratory monitoring
       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.
Vasopressor / Inotropic Drugs

   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

   Blocks the effects of the sympathetic nerve
    stimulation, endogenous catecholamine and
    adrenergic drugs.
Mechanism of Action

   Act on alpha or beta receptors
   Receptors are blocked by adrenergic
    antagonists or pre-synaptic alpha 2 receptors
    are stimulated.
When Used?

   To manage hypertension and a number of
    cardiovascular disorders.
Anti – hypertensive Medication

   Clonidine: Catapres, Catapres TTS, Dixarit,
    Duracion
   Pharmacologic classification: adrenergic
    (centrally acting)
   Therapeutic classification: antihypertensive
Clonidine

   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

   Cholinergic drugs stimulate the
    parasympathetic nervous system.
Mechanism of Action

   Direct acting cholinergic drugs are synthetic
    derivative of choline.
   Effects of drug
       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

   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

   Urinary retention
       Bladder distention
       Fluid intake
       Time of last void
   How do you know drug is working?
       Fluid intake equal to urine output
       Patient has voided within the last 8 hours
Nursing Assessment: paralytic ileus

   Paralytic ileus
       Hypo-peristalsis
       Decreased bowel sounds
       No gas or bowel movement
   How do you know drug is working?
       Bowel sounds heart in all four quadrants
       Client states has passes gas
       Client states has had a bowel movement
Nursing Assessment: Myasthenia Gravis

   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

   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

   May be used in myasthenia gravis or
    Alzheimer’s disease
Contraindications

   Renal obstruction
   Liver disease
Anticholinergic Drugs


    Chapter 20
    Clinical Drug Therapy
Anticholinergic Drugs

   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

   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

   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

   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

   Hyperthermia, hot, dry flushed skin, dry
    mouth, tachycardia, delirium, paralytic ileus
    and urinary retention
Atropine

   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

   Therapeutic effects:
       Increased heart rate
       Decreased GI and respiratory secretions
       Reversal of muscarinic effects
       May have spasmodic action on the biliary and
        genitourinary tracts.
Atropine

   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

								
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