Download Chapter 7 Respiratory Drugs

Chapter 7
Respiratory Drugs
1
Ventilation
 Refers to the movement of air in and out
of the lungs through a series of air
passages.
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Nose
Mouth
Trachea
Bronchial tree
 The upper portion of the respiratory
system is mainly responsible for
conditioning inhaled air from the
environment.
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 To maintain normal ventilatory function, it
is critical that the upper respiratory
system adjust the temperature and
humidify the inhaled air as well as
provide filtration of the contaminants in
the ambient air.
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 Filtration of inspired air occurs mainly as
the inhaled air passes over the mucus
lined epithelium of the trachea.
 The branches of the bronchial tree are
lined with smooth muscle, which adjusts
the constriction and dilation of the
airways in response to the needs of the
body.
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Respiratory System
 In the respiratory system, receptor
specificity is a very important issue and
has prompted a continued development
in many of the agents discussed in this
chapter.
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 One of the major systems regulating the
respiratory system is the autonomic
nervous system
 A main function of the autonomic nervous
system is to regulate smooth muscle tone in
the respiratory system and thereby maintain
the balance between bronchoconstriction
and bronchodilation.
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Asthma
 Millions of people in the United States
have asthma and billions of dollars are
spent annually on the care of these
individuals.
 Asthma is a condition of the respiratory
system involving narrowing
(bronchoconstriction) and inflammation of
the small air passages of the lower
respiratory system.
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 Technically, asthma, exercise induced
asthma (EIA), and exercise induced
bronchoconstriction (EIB) are separate
conditions and treated differently.
 True asthma is characterized by both
bronchoconstriction and inflammation in
the respiratory tract.
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 Exercise is a trigger for approximately
80% to 90% of individuals with asthma.
 Individuals with EIA, must have excellent
control of their underlying asthma in
order to be able to prevent asthma
exacerbations during physical activity
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 Exercise-induced bronchoconstriction
without active inflammation is technically
not exercise induced asthma.
 Exercise-induced bronchoconstriction
occurs in approximately 11% of
individuals without asthma and the rate
may be as high as 50% for elite athletes.
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 In asthmatic reaction, inflammatory
response = increase in mucus production
to protect body
 Excess coating can lead to air-flow
restriction
 Another mechanism to protect body is
bronchoconstriction
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 The classic signs of an acute asthma
exacerbation are:
 Shortness of breath
 Wheezing following exercise
 Other signs and symptoms include:
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Cough
Headache
Stomach cramps
Pain or tightness in the chest
Nausea
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 These signs and symptoms typically start
6 to 8 minutes after the onset of
strenuous exercise but may not reach
maximum severity until up to 15 minutes
after the cessation of exercise.
 Typically, spontaneous return to baseline
respiratory function occurs within a 20- to
60-minute period following onset of
symptoms.
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Asthma Treatment
Options
 Certified athletic trainers often interact
with athletes who use an inhaler, or more
formally known as metered dose inhalers
(MDIs).
 Most true asthma exacerbations have
both an inflammatory and
bronchoconstriction component.
 The use of medications to control and treat
asthma may address one or both of these
problems.
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 Currently, the most widely accepted
approach to asthma treatment is to
initially control the inflammatory process
associated with the trigger and thus
prevent bronchoconstriction onset.
 This approach is reflected in the switch
from heavy dependence on “rescue”
inhalers to the increased use of
controlling agents.
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 With respect to exercise-induced asthma,
the athlete typically experiences little or
no active inflammatory process and the
primary complication is the
bronchoconstriction associated with the
exercise trigger.
 The treatment for asthma and EIA are
different.
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 Asthma exacerbations are categorized based
on the severity and the frequency of the
symptoms.
 In general, asthma is broken down into four
categories: (Table 7-1, pg 95)
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mild intermittent
mild persistent
moderate persistent
severe persistent
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Commonly Used Drugs for
Asthma Control
 Numerous pharmacological approaches are
used to treat asthma.
 Some factors that influence the choice of
approach are severity and frequency of the
exacerbations, as well as the convenience of
using the drug.
 The drugs used to treat asthma can be
classified into two groups:
 bronchodilators and anti-inflammatory agents
(steroids and non-steroids).
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 It is generally accepted that anyone with
persistent asthma should utilize a
controlling agent for the inflammatory
component in conjunction with a “rescue”
inhaler for the bronchoconstriction.
 The role of corticosteroids in asthma, and
respiratory care in general, is to combat
inflammation of the airways associated
with certain respiratory conditions.
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 Corticosteroids indirectly prevent
inflammation-mediated
bronchoconstriction through the inhibition
of prostaglandins and leukotrienes.
 In addition, corticosteroids reverse
vascular permeability associated with the
inflammation process.
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 Oral nonsteroidal asthma medications
are an attractive alternative to the use of
inhaled steroids in the control of asthma.
 In addition, there is no fluctuation in
delivery of the medication due to
improper use of the MDI.
 It is important to note that all individuals
who use either steroids or nonsteroidals
still need access to a “rescue” inhaler in
the event of an asthma exacerbation
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Rescue Inhalers
 Table 7-2, pg 96
Exercise-induced Asthma
 Causes:
 water loss
 heat exchange cooling the airways
 Increased sodium intake
 Must have formal diagnosis
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Adverse Effects of
Asthma Medications
 MDIs have less serious adverse effects
 Localized delivery of the medication
 The adverse effects of beta-2 agonists are
relatively minor.
 Common adverse effects include
nervousness, restlessness, trembling, throat
irritation, and potential airway hypersensitivity.
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 Inhaled steroids, have localized side
effects, such as throat irritation and
hoarseness.
 The inhaled steroid residue present in the
mouth alters the bacterial environment,
thus allowing for opportunistic yeast
infections in the mouth.
 To limit this problem, users are
encouraged to rinse their mouth and brush
their teeth after each use of an inhaler.
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 Oral steroids short-term and long-term
adverse effects.
 Short term – increased appetite, acne, poor
wound healing, fluid retention, and insomnia
 Long-term – avascular necrosis, osteoporosis,
glaucoma, and decreased muscle mass
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 Adverse effects of inhaled nonsteroidal
asthma medications
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Bitter taste in mouth
Throat irritation
Dry mouth
Headache
Skin rash
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Allergies
 Are the result of some adverse
environmental stimulus
 Two classes of drugs are used for the
treatment of allergies:
 Antihistamines
 Corticosteroids (nasal sprays).
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Histamines
 Histamine causes blood vessel dilation
and subsequently an inflammatory
response in the area affected.
 Results in an inflammatory response noted by
the classic allergy symptoms, such as runny
nose, itchy and watery eyes, and sneezing.
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Antihistamines
 Antihistamines produce three general
effects on the body:
 Alteration of histamine action
 Sedation
 Anticholinergic activity (decreased salivation,
dry mouth, and constipation)
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 Currently there are first- and secondgeneration antihistamines
 The major differences between the two
generations are:
 The time they are active
 1st generation = 4 to 6 hrs
 2nd generation = up to 12 hrs
 The extent to which they promote
drowsiness
 2nd generation are less sedating
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 Antihistamine drugs
 Halt increased vascular permeability
 Decrease smooth muscle constriction of the
airways
 First-generation antihistamines cross the
blood brain barrier and cause sedation
 Use a first-generation antihistamine
during the evening (less expensive) and
nighttime
 Switch to a second-generation
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antihistamine during the daytime
 Antihistamines result in decreased
symptoms and increased patient comfort.
 Their use is sometimes questioned.
 Impeding these effects is not always a
good thing.
 The body produces mucus in an effort to
protect the respiratory system.
 Decreasing these functions may slow
recovery.
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 Antihistamines may not be effective in
decreasing nasal blockage.
 Second-generation antihistamines are
available with a decongestant.
 Claritin-D and Allegra-D
 A decongestant will assist with the
resolution of the runny nose and head
congestion.
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 Adverse effects of antihistamines
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Mucous membrane dryness
Cardiac stimulation
Blurred vision
Urinary retention
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Steroid Nasal Spray
 Nasal steroid medications are specifically
used for allergic rhinitis.
 They are not for symptoms of the common
cold.
 Drugs are delivered locally.
 Potential for nasal irritation, dryness, and
epistaxis
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Coughs and Colds
 Runny nose, mild sore throat, and watery
eyes are similar in both the common cold
and allergic reactions.
 Common cold refers to a nonbacterial
infection of the upper respiratory system.
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Cough and Cold Medications
 Decongestants
 vasoconstriction resulting in mucosal drying
 Antihistamines
 combat increased histamine = nasal
congestion and mucosal irritation
 Expectorants
 facilitate the removal of mucous from the
respiratory system
 Antitussives
 work to suppress coughing
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 Medications may contain a combination
of decongestant, antihistamine,
expectorant, and antitussive agents
 Vicks NyQuil contains:
 Acetaminophen
 Pseudoephedrine, a decongestant,
 Dextromethorphan, a cough suppressant
 Antihistamine
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Decongestants
 Prolonged use of decongestants:
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Headache
Nausea
Dry mouth and nose
Dizziness
Nervousness
 Prolonged application of nasal spray
(topical)
 Can cause a rebound effect vasodilatation
after the initial vasoconstriction decreases
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 Common decongestants
 Pseudoephedrine (Sudafed)
 Tetrahydroziline (Visine)
 Oxymetazoline (Afrin)
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Expectorants
 Cough syrup to relieve the coughing
linked to cold symptoms
 Cough syrups can contain
 Antitussive (cough suppressant)
 Expectorant (promotes mucus clearance)
 If the coughing linked with a cold is
“nonproductive,” eliminate the
nonproductive coughing
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 Mucus removal produced by the body
during the common cold needs to be thin
and mobile for the coughing to be
productive.
 Expectorants are available in two forms:
 Mucolytic
 Stimulant
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Antitussives
 Antitussives suppress the cough.
 Use a central or a local mechanism.
 Used for short periods of time.
 Used to inhibit a cough via a central
mechanism.
 Cough center located in the medulla is
targeted.
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 Dextromethorphan (DM) is the most
common ingredient in OTC suppressing
agents.
 Robitussin products, Tylenol cold products,
and NyQuil medications.
 Physician can prescribe a narcotic
antitussive.
 Codeine or hydrocodone.
 Addictive property of narcotics.
 Duration of the prescription does not exceed
1 week.
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Adverse Effects
 OTC cold and allergy medications
relatively show few serious adverse
effects.
 Participating in a sport while in a state of
drowsiness could be dangerous.
 Antihistamines (1st generation) can result
in significant drowsiness even after the
drug’s half-life is complete.
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 Antihistamines may cause anticholinergic
effects such as
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Mucus membrane dryness
Cardiac stimulation
Decreased gastrointestinal activity
Urinary retention
 Decongestants can promote
 Excessive drying of the nose and throat
 Tachycardia and restlessness
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 Guaifenesin (cough syrups)
 Dizziness
 Headache
 Nausea
 Antitussives (Dextromethorphan)
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Mild dizziness
Drowsiness
Nausea
Stomach cramps
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