Transcript Drugs Affecting the Respiratory System

Bronchodilators and Other
Respiratory Drugs
 Asthma
 Emphysema
 Chronic
bronchitis
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Recurrent and reversible shortness of breath
Airways become narrow as a result of:
• Bronchospasm
• Inflammation & Edema of the bronchial mucosa
• Production of viscid mucus
Alveolar ducts/alveoli remain open, but airflow to them is
obstructed
Symptoms
• Wheezing
• Difficulty breathing
 Status
asthmaticus
• Prolonged asthma attack that does not respond
to typical drug therapy
• May last several minutes to hours
• Medical emergency
 Continuous
inflammation of the bronchi
and bronchioles
 Often
occurs as a result of prolonged
exposure to bronchial irritants
 Characterized
by
• Hypoxemia
• Chronic productive cough
• “Blue Bloater”
 Air
spaces enlarge as a result of the
destruction of alveolar walls
 The
surface area where gas exchange
takes place is reduced
 Effective
respiration is impaired
 Characterized by:
• Increased paCO2 - respiratory acidosis
• Difficulty exhaling – pursed lip breathing
• “Pink Puffer”
 Long-term control
• Antileukotrienes
• cromolyn
• Inhaled steroids
• Long-acting β2-agonists
 Quick relief
• Intravenous systemic corticosteroids
• Short-acting inhaled β2-agonists
 Bronchodilators
• β-adrenergic agonists
• Xanthine derivatives
 Anticholinergics
 Antileukotrienes
 Corticosteroids
 Large
group, sympathomimetics
 Used
during acute phase of asthmatic
attacks
 Quickly
reduce airway constriction
β2-adrenergic receptors
throughout the lungs
 Stimulate
Three types
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Nonselective adrenergics
• Stimulate α, β1 (cardiac), and β2 (respiratory) receptors
• Example: epinephrine
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Nonselective β-adrenergics
• Stimulate both β1 and β2 receptors
• Example: metaproterenol
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Selective β2 drugs
• Stimulate only β2 receptors
• Example: albuterol (Proventil)
Mechanism of Action
 Begins
 Ends
at the specific receptor stimulated#
with the dilation of the airways
• #Activation of β2 receptors activates cAMP,*
which relaxes smooth muscles of the airway and
results in bronchial dilation and increased
airflow
*cAMP = cyclic adenosine monophosphate
Indications
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Relief of bronchospasm related to asthma, bronchitis, and
other pulmonary diseases
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Useful in treatment of acute attacks as well as prevention
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Used in hypotension and shock
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Used to produce uterine relaxation to prevent premature
labor
Hyperkalemia—stimulates potassium to shift into the
cell
α-β (epinephrine)
Insomnia
 Restlessness
 Anorexia
 Vascular headache
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Hyperglycemia
 Tremor
 Cardiac stimulation
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β1 and β2 (metaproterenol)
Cardiac stimulation
 Tremor
 Anginal pain
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Vascular headache
 Hypotension
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β2 (albuterol)
Hypotension OR hypertension
 Vascular headache
 Tremor
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Thorough assessment before beginning therapy
• Skin color
• Baseline vital signs
• Respirations (should be between 12 and 24
•
•
•
•
•
breaths/min)
Respiratory assessment, including PO2
Sputum production
Allergies
History of respiratory problems
Other medications
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Monitor for therapeutic effects
• Decreased dyspnea
• Decreased wheezing, restlessness, and anxiety
• Improved respiratory patterns with return to normal rate
and quality
• Improved activity tolerance
Patients should know how to use inhalers and MDIs
•
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Have patients demonstrate use of devices
Monitor for adverse effects
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Patients should be encouraged to have a good state of health
• Avoid exposure to conditions that precipitate bronchospasms
(allergens, smoking, stress, air pollutants)
• Adequate fluid intake
• Compliance with medical treatment
• Avoid excessive fatigue, heat, extremes in temperature, caffeine
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Patients to get prompt treatment for flu or other illnesses
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Patients to get vaccinated against pneumonia and flu
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Check with their physician before taking any medication, including
OTCs
Teach patients to take bronchodilators exactly as prescribed
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Albuterol, if used too frequently, loses its β2-specific
actions at larger doses
• As a result, β1 receptors are stimulated, causing nausea,
increased anxiety, palpitations, tremors, and increased
heart rate
Take medications exactly as prescribed
•
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No omissions or double doses
Report insomnia, jitteriness, restlessness, palpitations,
chest pain, or any change in symptoms
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For any inhaler prescribed, ensure that the patient is
able to self-administer the medication
• Provide demonstration and return demonstration
• Ensure the patient knows the correct time intervals
for inhalers
• Provide a spacer if the patient has difficulty
coordinating breathing with inhaler activation
• Ensure that patient knows how to keep track of the
number of doses in the inhaler device
Mechanism of Action
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Acetylcholine (ACh) causes bronchial constriction and
narrowing of the airways
Anticholinergics bind to the ACh receptors, preventing ACh
from binding
Result:
• bronchoconstriction is prevented
• airways dilate
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ipratropium bromide (Atrovent) and tiotropium (Spiriva)
Slow and prolonged action
Used to prevent bronchoconstriction
NOT used for acute asthma exacerbations!
Adverse effects
 Dry
mouth or throat
 Nasal congestion
 Heart palpitations
 Gastrointestinal distress
 Headache
 Coughing
 Anxiety
No known drug interactions
 Plant
alkaloids:
• caffeine, theobromine, and theophylline
 Only
theophylline is used as a bronchodilator
 Synthetic
xanthines:
(IV) theophylline (Aminophylline)
(oral) theophylline (Elixophyllin, Theo-Dur)
 Increase
levels of energy-producing cAMP
• This is done competitively inhibiting
phosphodiesterase (PDE), the enzyme that breaks
down cAMP (cAMP = cyclic adenosine monophosphate)
 Result:
• decreased cAMP levels, smooth muscle relaxation,
bronchodilation, and increased airflow
• cardiovascular stimulation: increased force of contraction and
increased heart rate, resulting in increased cardiac output and
increased blood flow to the kidneys (diuretic effect)
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Dilate of airways in asthma, chronic bronchitis, and
emphysema
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Mild to moderate cases of acute asthma
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Adjunct drug in the management of COPD
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Not used as frequently due to:
• potential for drug interactions
• variables related to drug levels in the blood
 Nausea,
vomiting, anorexia
 Gastroesophageal
reflux during sleep
 Sinus
tachycardia, extrasystoles,
palpitations, ventricular dysrhythmias
 Transient
increased urination
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Contraindications: history of PUD or GI disorders
Cautious use: cardiac disease
Timed-release preparations should not be crushed or
chewed (causes gastric irritation)
Report to physician:
• Palpitations
• Weakness
Nausea
Dizziness
Vomiting
Chest pain
• Convulsions
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Interactions with cimetidine, oral contraceptives,
allopurinol, certain antibiotics elevate serum xanthine
blood levels
Nicotine & caffeine potentiate cardiac effects
St. John’s wort increases metabolism = decrease blood
levels
 Also
called
leukotriene receptor antagonists (LRTAs)
 Newer
class of asthma drugs
Currently available drugs
 montelukast (Singulair)
 zafirlukast (Accolate)
 zileuton (Zyflo)
 Leukotrienes
• substances released when a trigger, such as cat
hair or dust, starts a series of chemical reactions
in the body
• cause inflammation, bronchoconstriction, and
mucus production
 Result:
coughing, wheezing, shortness of breath
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Antileukotriene drugs
•
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prevent leukotrienes from attaching to receptors on cells in and in
circulation
Inflammation in the lungs is blocked
Asthma symptoms are relieved
By blocking leukotrienes:
 Prevent smooth muscle contraction of the bronchial
airways
 Decrease mucus secretion
 Prevent vascular permeability
 Decrease neutrophil and leukocyte infiltration to the lungs,
preventing inflammation
 Prophylaxis
and chronic treatment of
asthma in adults and children older than
age 12
 NOT
meant for management of acute
asthmatic attacks
 montelukast (Singulair)
• is approved for use in children ages 2 and older,
and for treatment of allergic rhinitis
zileuton (Zyflo)
Headache
Dyspepsia
Nausea
Dizziness
Insomnia
Liver dysfunction
zafirlukast (Accolate)
Headache
Nausea
Diarrhea
Liver dysfunction
Montelukast (Singulair) has fewer adverse effects
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Ensure that the drug is being used for chronic
management of asthma, not acute asthma
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Teach the patient the purpose of the therapy
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Improvement should be seen in about 1 week
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Check with physician before taking any OTC or prescribed
medications—many drug interactions
Assess liver function before beginning therapy
Medications should be taken every night on a continuous
schedule, even if symptoms improve
 Anti-inflammatory!!!
 Uses
 Do
- chronic asthma/COPD exacerbations
not relieve acute asthmatic attacks S&S
 Oral, IV
(quick acting), or inhaled forms
 Inhaled forms reduce systemic
• May take several weeks before full
effects are seen
effects
Mechanism of Action
 Stabilize
membranes of cells that release
harmful bronchoconstricting substances
 Also
increase responsiveness of bronchial
smooth muscle to β-adrenergic
stimulation
 beclomethasone
dipropionate
(Beclovent, Vanceril)
 triamcinolone
acetonide (Azmacort)
 dexamethasone
sodium phosphate
(Decadron Phosphate Respihaler)
 fluticasone
(Flovent, Flonase)
 Treatment
of bronchospastic disorders
that are not controlled by conventional
bronchodilators
 NOT
considered first-line drugs for
management of acute asthmatic attacks
or status asthmaticus
 Pharyngeal
irritation
 Coughing
 Dry
mouth
 Oral
fungal infections
 Systemic
effects are rare because of the
low doses used for inhalation therapy
 Contraindicated
in patients with psychosis, fungal
infections, AIDS, TB
 Teach
patients to gargle and rinse the mouth with
lukewarm water afterward to prevent the
development of oral fungal infections
a β-agonist bronchodilator and corticosteroid
inhaler are both ordered, the bronchodilator
should be used several minutes before the
corticosteroid to provide bronchodilation before
administration of the corticosteroid
 If
 Teach
patients
• to monitor disease with a peak flow meter
• use of a spacer device to ensure successful
inhalations
• keep inhalers and nebulizer equipment clean
after uses
• Tapering doses of oral corticosteroids
1.
Doses of xanthine derivatives may need to be reduced in older adult patients.
True or false? Explain your answer.
2. The therapeutic blood level of theophylline in the adult is _____________
3. Theophylline is classified as a _____________ _____________, whereas albuterol
(Proventil) and epinephrine (Medinhaler-Epi) are _____________________
______________.
4. β-agonists are contraindicated in patients with _________ or _________ disorders.
5.
Antileukotriene drugs reduce _______________ associated with asthma, and are
used for chronic/acute asthma.
6. This antileukotriene drug is US Food and Drug Administration (FDA) approved
for use in children 2 years of age and older: ___________________.
1.
Lower doses in the older adult may be necessary initially and during therapy
with close monitoring for adverse effects and toxicity (cardiovascular and
central nervous system [CNS] stimulation).
2. The therapeutic blood level of theophylline in the adult is 10 to 20 mcg/mL; some
practitioners recommend 5 to 15 mcg/mL
3. Theophylline is classified as a xanthine derivative, whereas albuterol and
epinephrine are β-agonist bronchodilators.
4. β-agonists are contraindicated in patients with a high risk of stroke or any
cardiovascular disorders, particularly tachydysrhythmias.
5. Antileukotriene drugs reduce inflammation associated with asthma, and are used
for chronic asthma.
6. This antileukotriene drug is US Food and Drug Administration (FDA) approved
for use in children 2 years of age and older: montelukast (Singulair).
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For each drug listed, state whether it is used for:
A. Asthma prophylaxis and maintenance treatment
B. Treatment of acute bronchospasm
C. Both
1. montelukast (Singulair), an antileukotriene
2. theophylline (Theo-Dur) oral tablets, xanthine-derived
3. fluticasone (Flovent), a synthetic glucocorticoid
4. ipratropium (Atrovent), an anticholinergic
5. albuterol Proventil) inhaler, a β1 agonist
6. epinephrine, intravenous dose, an alpha-beta agonist
1.
A
2.
A (not used as much now for relief of acute symptoms,
especially the oral form)
3.
A
4.
C
5.
C
6. B (for the IV form)