Download Chapter 44

Clinical Drug Therapy
Chapter 44 – Drugs for Asthma and Other
Bronchoconstrictive Disorders
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Bronchoconstrictive Disorder
Characteristics
• Bronchoconstriction
• Inflammation, mucosal edema
• Excessive mucus production
– Asthma
– Bronchitis
– Emphysema
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Question
Is the following statement True or False?
Asthma occurs only in children.
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Answer
False.
Asthma may occur at any age but is especially
common in children. Children who are
exposed to allergens and airway irritants
(tobacco smoke, etc) during infancy are at
high risk for developing asthma.
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Asthma
• Characteristics
– Bronchoconstriction, inflammation
– Hyperactivity to stimuli
• Symptoms
– Dyspnea, wheezing, chest tightness
– Cough, sputum production
• GERD association
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Asthma Pathophysiology
• Bronchoconstriction narrows airways
– Sphincter action can completely occlude
airway
– Aggravated by inflammation, mucosal
edema, excessive mucus
• Mast cells release substances in response to
causative stimuli  bronchoconstriction and
inflammation
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Chronic Obstructive Pulmonary Disease
• AKA, COPD
• Chronic bronchitis, emphysema
– Usually develops with long-standing
exposure to airway irritants
•Eg, cigarette smoke
– Symptoms are
•More constant, less reversible
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Bronchoconstriction Drug Therapy
• Drug classifications
– Long-term control (prophylactic)
•Achieve and maintain control of
persistent asthma
– Quick relief (rescue)
•Used during periods of acute symptoms
and exacerbations
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Bronchoconstriction Drug Therapy (cont.)
• Bronchodilators
– Prevent, treat bronchoconstriction
• Anti-inflammatory medications
– Prevent, treat airway inflammation
– Reduce bronchoconstriction
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Question
Is the following statement True or False?
Two major groups of drugs used to treat
asthma and COPD are bronchodilators and
anti-inflammatory medications.
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Answer
True.
Two major groups of drugs used to treat
asthma, acute and chronic bronchitis, and
emphysema are bronchodilators and antiinflammatory medications. Bronchodilators
prevent/treat bronchoconstriction; antiinflammatories prevent/treat airway
inflammation.
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Bronchodilators
• Adrenergics
– Stimulate receptors in bronchi and
bronchioles
•Producing bronchodilation
– Adverse effects
•Cardiac stimulation
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Bronchodilators (cont.)
• Anticholinergics
– Block the action of acetylcholine in
bronchial smooth muscle
•Reduces bronchoconstrictive substance
release
• Adverse effects
– Cough, nervousness, nausea, GI upset,
headache, dizziness
– Vary depending on medication used
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Anti-inflammatory Agents
• Corticosteroids
– Treat acute and chronic asthma, other
bronchoconstrictive disorders
– Resulting in
• Mucus secretion
• Airway mucosa edema
•Repaired epithelium damage
•Reduced airway reactivity
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Anti-inflammatory Agents (cont.)
• Leukotriene modifier drugs
– Long-term treatment of asthma
– Prevent acute asthma attacks induced by
•Allergens, exercise, cold air,
hyperventilation, irritants, NSAIDs
– Not effective in relieving acute attacks
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Anti-inflammatory Agents (cont.)
• Mast cell stabilizers
– Prevent release of bronchoconstrictive
and inflammatory substances
•In response to allergens, other stimuli
– Used in prophylaxis of acute asthma in
mild, persistent asthma
– Not effective in acute bronchospasm or
status asthmaticus
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Question
Is the following statement True or False?
In acute, severe asthma, a topical
corticosteroid (in relatively high doses) is
indicated for a patient whose respiratory
distress is not relieved by an inhaled beta2
agonist.
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Answer
False.
In acute, severe asthma, a systemic
corticosteroid (in relatively high doses) is
indicated for a patient whose respiratory
distress is not relieved by an inhaled beta2
agonist. A topical corticosteroid will not be
effective against airway inflammation.
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Drug Selection, Administration Guidelines
• Selective, short-acting adrenergic agonist is
initial drug of choice for acute bronchospasm
• Direct action of inhaled medications on
airways can be given in smaller doses with
fewer adverse effects than oral or parenteral
medications
• Inhaled corticosteroids are used early in
disease process when inflammation is
established as major asthmatic component
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Drug Selection, Administration Guidelines
(cont.)
• In chronic disorders, inhaled corticosteroids
should be taken on regular schedule using
lowest dose required to control symptoms
• Multidrug regimens offer advantage of
smaller doses of each medication, which can
decrease adverse effects, allow dosage
increase as needed in exacerbations
• Drug dosing must be individualized to attain
most therapeutic effects with fewest adverse
effects
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Recognition of Management of Toxicity
• Most likely to occur because of overuse of
bronchodilators in efforts to relieve dyspnea
• Bronchodilator overdose adverse effects
– Excessive cardiac stimulation
•Angina, tachycardia, palpitations,
serious dysrhythmias, cardiac arrest
– Excessive CNS stimulation
•Agitation, anxiety, insomnia, seizures,
tremors
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Use in Special Populations
• Children
• Older adults
• Renal impairment
• Hepatic impairment
• Critical illness
• Home care
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