Drugs affecting the respiratory system

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Drugs affecting the respiratory system

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1. Antihistamines2. Decongestants3. Antitussives4. Expectorants5. Bronchodilators6. Beta adrenergic agonist7. Anticholinergics8. Antileukotriene agents9. Corticosteroids10. Mast cell stablizers

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Understanding the Common Cold

Most caused by viral infection

(rhinovirus or influenza virus—the “flu”)

Virus invades tissues (mucosa) of upper respiratory

tract, causing upper respiratory infection (URI)

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Treatment of the Common Cold

Involves combined use of antihistamines, nasal

decongestants, antitussives, and expectorants

Treatment is symptomatic only, not curative

Symptomatic treatment does not eliminate the

causative pathogen

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Treatment of the Common Cold (cont’d)

Difficult to identify whether cause is viral or


Treatment is “empiric therapy,” treating the most

likely cause

Antivirals and antibiotics may be used, but a

definite viral or bacterial cause may not be easily


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Drugs that directly compete with histamine

for specific receptor sites

Two histamine receptors

H1 (histamine1)

H2 (histamine2)

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Antihistamines (cont’d)

H1 histamine receptor- found on smooth muscle, endothelium, and central nervous system tissue; causes vasodilation, bronchoconstriction, smooth muscle activation, and separation of endothelia cellss (responsible for hives), and pain and itching due to insect stings

H1 antagonists are commonly referred to as antihistamines Antihistamines have several properties

Antihistaminic Anticholinergic Sedative

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Antihistamines (cont’d)

H2 blockers or H2 antagonists

Used to reduce gastric acid in PUD

Examples: cimetidine, ranitidine, famotidine

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Antihistamines (cont’d)

10% to 20% of general population is sensitive to various environmental allergies

Histamine-mediated disorders Allergic rhinitis (hay fever, mould and dust allergies) Anaphylaxis Angioneurotic edema Drug fevers Insect bite reactions Urticaria (itching)

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Antihistamines: Mechanism of Action

Block action of histamine at the H1 receptor sites

Compete with histamine for binding at unoccupied


Cannot push histamine off the receptor if already


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Antihistamines: Mechanism of Action (cont’d)

The binding of H1 blockers to the histamine

receptors prevents the adverse consequences of

histamine stimulation Vasodilation

Increased GI and respiratory secretions

Increased capillary permeability

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Antihistamines: Mechanism of Action (cont’d)

More effective in preventing the actions of

histamine rather than reversing them

Should be given early in treatment, before all

the histamine binds to the receptors

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Antihistamines: Indications

Management of: Nasal allergies Seasonal or perennial allergic rhinitis

(hay fever) Allergic reactions Motion sickness Sleep disorders

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Antihistamines: Indications (cont’d)

Also used to relieve symptoms associated with

the common cold

Sneezing, runny nose

Palliative treatment, not curative

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Antihistamines: Side effects

Anticholinergic (drying) effects, most common Dry mouth Difficulty urinating Constipation Changes in vision

Drowsiness Mild drowsiness to deep sleep

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Antihistamines: Two Types


Nonsedating/peripherally acting

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Traditional Antihistamines

Older Work both peripherally and centrally Have anticholinergic effects, making them

more effective than nonsedating agents in some cases Examples: Benedryl (diphenhydramine)

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Nonsedating/Peripherally Acting Antihistamines

Developed to eliminate unwanted side effects, mainly sedation

Work peripherally to block the actions of histamine; thus, fewer CNS side effects

Longer duration of action (increases compliance)

Examples: reactine, allegra

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Antihistamines:Nursing Implications

Gather data about the condition or allergic reaction that required treatment; also assess for drug allergies

Contraindicated in the presence of acute asthma attacks and lower respiratory diseases

Use with caution in increased intraocular pressure, cardiac or renal disease, hypertension, asthma, COPD, peptic ulcer disease, BPH, or pregnancy

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Antihistamines:Nursing Implications (cont’d)

Instruct clients to report excessive sedation, confusion, or hypotension

Avoid driving or operating heavy machinery, and do not consume alcohol or other CNS depressants

Do not take these medications with other prescribed or OTC medications without checking with prescriber

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Antihistamines:Nursing Implications (cont’d)

Best tolerated when taken with meals—reduces GI upset

If dry mouth occurs, teach client to perform frequent mouth care, chew gum, or suck on hard candy to ease discomfort

Monitor for intended therapeutic effects

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Nasal Congestion

Excessive nasal secretions

Inflamed and swollen nasal mucosa

Primary causes


Upper respiratory infections (common cold)

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Decongestants: Types (cont’d)

Two dosage forms


Inhaled/topically applied to the nasal membranes

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Oral Decongestants

Prolonged decongestant effects, but delayed onset

Effect less potent than topical No rebound congestion Exclusively adrenergics Example: pseudoephedrine, Sinutab, Dristan,

Tylenol cold, Sudafed

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Topical Nasal Decongestants

Topical adrenergics Prompt onset Potent Sustained use over several days causes rebound congestion,

making the condition worse Eg:


COMPOSITION:Each 1 mL of solution contains:        Phenylephrine HCl        5 mg        Pheniramine Maleate        2 mg

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Topical Nasal Decongestants (cont’d)

Adrenergics desoxyephedrine phenylephrine

Intranasal steroids beclomethasone dipropionate flunisolide fluticasone

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Nasal Decongestants:Mechanism of Action

Site of action: blood vessels surrounding nasal sinuses Adrenergics

Constrict small blood vessels that supply URI structures

As a result these tissues shrink, and nasal secretions in the swollen mucous membranes are better able to drain

Nasal stuffiness is relieved

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Nasal Decongestants:Mechanism of Action (cont’d)

Site of action: blood vessels surrounding nasal sinuses Nasal steroids

Anti-inflammatory effect Work to turn off the immune system cells involved in

the inflammatory response Decreased inflammation results in decreased congestion Nasal stuffiness is relieved

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Nasal Decongestants: Indications

Relief of nasal congestion associated with: Acute or chronic rhinitis

Common cold


Hay fever

Other allergies

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Nasal Decongestants: Indications (cont’d)

May also be used to reduce swelling of the

nasal passage and facilitate visualization of

the nasal/pharyngeal membranes before

surgery or diagnostic procedures

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Nasal Decongestants: Side Effects

Adrenergics Steroids

Nervousness Local mucosal dryness

Insomnia and irritation



(systemic effects due to adrenergic stimulation of theheart, blood vessels, and CNS)

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Nasal Decongestants:Nursing Implications

Decongestants may cause hypertension, palpitations, and CNS stimulation—avoid in clients with these conditions

Clients on medication therapy for hypertension should check with their physician before taking OTC decongestants

Assess for drug allergies

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Nasal Decongestants:Nursing Implications (cont’d)

Clients should avoid caffeine and caffeine-

containing products

Report a fever, cough, or other symptoms lasting

longer than a week

Monitor for intended therapeutic effects

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Cough Physiology

Respiratory secretions and foreign objects are naturally removed by the: Cough reflex

Induces coughing and expectoration Initiated by irritation of sensory receptors in the

respiratory tract

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Two Basic Types of Cough

Productive cough

Congested, removes excessive secretions

Nonproductive cough

Dry cough

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Most of the time, coughing is beneficial

Removes excessive secretions

Removes potentially harmful foreign substances

In some situations, coughing can be harmful, such as

after hernia repair surgery

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Most of the time, coughing is beneficial

Removes excessive secretions

Removes potentially harmful foreign substances

In some situations, coughing can be harmful, such as

after hernia repair surgery

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Antitussives: Definition

Drugs used to stop or reduce coughing

Opioid and nonopioid

(narcotic and nonnarcotic)

Used only for nonproductive coughs!

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Antitussives: Mechanism of Action

Opioids Suppress the cough reflex by direct action on the

cough centre in the medulla

Examples: codeine hydrocodone

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Antitussives: Mechanism of Action (cont’d)

Nonopioids Suppress the cough reflex by numbing the

stretch receptors in the respiratory tract and preventing the cough reflex from being stimulated

Examples: Dextromethorphan, Nyquil, Robitussin

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Antitussives: Indications

Used to stop the cough reflex when the cough is nonproductive and/or harmful

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Antitussives: Side Effects

Dextromethorphan Dizziness, drowsiness, nausea

Opioids Sedation, nausea, vomiting, lightheadedness,


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Antitussive Agents:Nursing Implications

Perform respiratory and cough assessment, and assess for allergies

Instruct clients to avoid driving or operating heavy equipment due to possible sedation, drowsiness, or dizziness

If taking chewable tablets or lozenges, do not drink liquids for 30 to 35 minutes afterward

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Antitussive Agents:Nursing Implications (cont’d)

Report any of the following symptoms to the caregiver Cough that lasts more than a week A persistent headache Fever Rash

Antitussive agents are for nonproductive coughs Monitor for intended therapeutic effects

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Expectorants: Definition

Drugs that aid in the expectoration

(removal) of mucus

Reduce the viscosity of secretions

Disintegrate and thin secretions

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Expectorants: Mechanisms of Action

Direct stimulation Reflex stimulation

Final result: thinner mucus that is easier to remove

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Expectorants: Mechanism of Action (cont’d)

Reflex stimulation Agent causes irritation of the GI tract Loosening and thinning of respiratory tract secretions occur

in response to this irritation Example: guaifenesin

Direct stimulation The secretory glands are stimulated directly to increase their

production of respiratory tract fluids Examples: iodine-containing products such as iodinated

glycerol and potassium iodide

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Expectorants: Drug Effects

By loosening and thinning sputum and

bronchial secretions, the tendency to cough is

indirectly diminished

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Expectorants: Indications

Used for the relief of nonproductive coughs associated with:Common coldBronchitisLaryngitisPharyngitisCoughs caused by chronic paranasal sinusitis


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Expectorants:Nursing Implications

Expectorants should be used with caution in the elderly or those with asthma or respiratory insufficiency

Clients taking expectorants should receive more fluids, if permitted, to help loosen and liquefy secretions

Report a fever, cough, or other symptoms lasting longer than a week

Monitor for intended therapeutic effects

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Bronchodilators and Other Respiratory Agents

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Table 36-2 Stepwise approach to the management of asthma

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Table 36-3 Mechanisms of anti-asthmatic drug action

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Diseases of the Lower Respiratory Tract

Bronchial asthma Emphysema Chronic bronchitis COPD Cystic fibrosis Acute respiratory distress syndrome

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Agents Used to Treat Asthma

Long-term control Antileukotrienes Cromoglycate Inhaled steroids Long-acting beta2-agonists

Quick relief Intravenous systemic corticosteroids Short-acting inhaled beta2-agonists

ipratropium nedocromil theophylline

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Bronchodilators and Respiratory Agents

Bronchodilators Xanthine derivatives Beta-adrenergic agonists

Anticholinergics Antileukotrienes Corticosteroids Mast cell stabilizers

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Bronchodilators: Xanthine Derivatives

Plant alkaloids: caffeine, theobromine, and theophylline

Only theophylline is used as a bronchodilator Examples:

aminophyllineTheophyllineSlo-Bid® Uniphyl®

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Xanthine Derivatives: Drug Effects

Cause bronchodilation by relaxing smooth muscles of the airways

Result: relief of bronchospasm and greater airflow into and out of the lungs

Also cause CNS stimulation Slow onset action and are mostly used for

prevention Aminophylline(Status asthmaticus)

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Xanthine Derivatives: Drug Effects (cont’d)

Also cause cardiovascular stimulation: increased force of contraction and increased HR, resulting in increased cardiac output and increased blood flow to the kidneys (diuretic effect)

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Xanthine Derivatives: Indications

Dilation of airways in asthmas, chronic

bronchitis, and emphysema

Mild to moderate cases of acute asthma

Adjunct agent in the management of COPD

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Xanthine Derivatives: Side Effects

Nausea, vomiting, anorexia

Gastroesophageal reflux during sleep

Sinus tachycardia, extrasystole, palpitations,

ventricular dysrhythmias

Transient increased urination

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Nursing Implications: Xanthine Derivatives

Contraindications: history of PUD or

GI disorders

Cautious use: cardiac disease

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Bronchodilators: Beta-Agonists

Large group, sympathomimetics Used during acute phase of asthmatic attacks Quickly reduce airway constriction and

restore normal airflow Stimulate beta2-adrenergic receptors

throughout the lungs

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Bronchodilators: Beta-Agonists (cont’d)

Three types Nonselective adrenergics

Stimulate alpha-, beta1- (cardiac), and beta2- (respiratory) receptors Example: epinephrine

Nonselective beta-adrenergics Stimulate both beta1- and beta2-receptors Example: isoproterenol

Selective beta2 drugs

Stimulate only beta2-receptors Example: salbutamol

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Beta-Agonists: Indications

Relief of bronchospasm related to asthma,

bronchitis, and other pulmonary diseases

Useful in treatment of acute attacks as well

as prevention

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Beta-Agonists: Side Effects

Beta2 (salbutamol)

Hypotension OR hypertension Vascular headaches Tremor Contraindicated: clients with allergies,

tachyarythmias, severe cardiac disease

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Nursing Implications

Encourage clients to take measures that promote a generally good state of health in order to prevent, relieve, or decrease symptoms of COPD 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,


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Nursing Implications (cont’d)

Perform a thorough assessment before beginning therapy, including: Skin colour Baseline vital signs Respirations (should be <12 or >24 breaths/min) Respiratory assessment, including SaO2

Sputum production Allergies History of respiratory problems Other medications

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Nursing Implications (cont’d)

Teach clients to take bronchodilators exactly as prescribed

Ensure that clients know how to use inhalers and MDIs, and have the clients demonstrate use of devices

Monitor for side effects

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Nursing Implications (cont’d)

Monitor for therapeutic effects Decreased dyspnea Decreased wheezing, restlessness, and anxiety Improved respiratory patterns with return to

normal rate and quality Improved activity tolerance

Decreased symptoms and increased ease of breathing

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Anticholinergics: Mechanism of Action

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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Atrovent (ipratropium bromide) is the only anticholinergic used for respiratory disease

Slow and prolonged action Used to prevent bronchoconstriction NOT used for acute asthma exacerbations! Combivent (salbutamol/ipratroprium)

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Anticholinergics (cont’d)

Side effects: Dry mouth or throat Gastrointestinal distress Headache Coughing Anxiety

No known drug interactions

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Also called leukotriene receptor antagonists


Newer class of asthma medications

Three subcategories of agents

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Antileukotrienes (cont’d)

Currently available agents:

Montelukast (sold as Singulair®)

Zafirlukast (sold as Accolate®)

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Antileukotrienes: Mechanism of Action

Leukotrienes are substances released when a trigger, such as cat hair or dust, starts a series of chemical reactions in the body

Leukotrienes cause inflammation, bronchoconstriction, and mucus production

Result: coughing, wheezing, shortnessof breath

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Antileukotrienes: Mechanism of Action (cont’d)

Antileukotriene agents prevent leukotrienes from attaching to receptors on cells in the lungs and in circulation

Inflammation in the lungs is blocked, and asthma symptoms are relieved

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Antileukotrienes: Drug Effects

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

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Antileukotrienes: Indications

Prophylaxis and chronic treatment of asthma in adults and children older than age 12

NOT meant for management of acute asthmatic attacks

Montelukast is approved for use in children ages 6 and older

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Antileukotrienes: Side Effects

zafirlukast Headache Nausea Diarrhea Liver dysfunction

montelukast has fewer side effects

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Antileukotrienes: Nursing Implications

Ensure that the drug is being used for chronic management of asthma, not acute asthma

Teach the client the purpose of the therapy Improvement should be seen in about

1 week

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Anti-inflammatory Used for chronic asthma Do not relieve symptoms of acute

asthmatic attacks Oral or inhaled forms Inhaled forms reduce systemic effects May take several weeks before full

effects are seen

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Corticosteroids: Mechanism of Action

Stabilize membranes of cells that release harmful bronchoconstricting substances

These cells are leukocytes, or white blood cells

Also increase responsiveness of bronchial smooth muscle to beta-adrenergic stimulation

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Inhaled Corticosteroids

Budesonide (Pulmicort®) Fluticasone (Flovent®)

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Inhaled Corticosteroids: Indications

Treatment of bronchospastic disorders that are not controlled by conventional bronchodilators

NOT considered first-line agents for management of acute asthmatic attacks or status asthmaticus

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Inhaled Corticosteroids: Side Effects

Pharyngeal irritation Coughing Dry mouth Oral fungal infections Systemic effects are rare because of the low

doses used for inhalation therapy

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Inhaled Corticosteroids: Nursing Implications

Contraindicated in client with psychosis, fungal infections, AIDS, TB

Cautious use in clients with diabetes, glaucoma, osteoporosis, PUD, renal disease, HF, edema

Teach clients to gargle and rinse the mouth with water afterward to prevent the development of oral fungal infections

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Inhaled Corticosteroids: Nursing Implications (cont’d)

Abruptly discontinuing these medications can lead to serious problems

If discontinuing, should be weaned for 1 to 2 weeks, only if recommended by physician

Report any weight gain of more than 2.5 kg a week or the occurrence of chest pain

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PO corticosteroids

Prednisolone (sold as Pediapred®) Prednisone (sold as Deltasone®)

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Combination Medications

Some pharmaceutical manufacturers have combined two controller medications into one inhaler. These inhalers are referred to as "Combination Medications".

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Combination medications

Combination ® Corticosteroids Budesonide (Pumicort®) Formoterol (Oxeze®) Long-Acting bronchodilator Fluticasone (Flovent®) Salmeterol (Severent®)

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Mast Cell Stabilizers

Cromoglycate (sold as Intal®) Nedocromil (sold as Tilade®) Ketotifen fumarate (sold as Zaditen®)

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Mast Cell Stabilizers: Indications

Adjuncts to the overall management of asthma Used solely for prophylaxis, NOT for

acute asthma attacks Used to prevent exercise-induced bronchospasm Used to prevent bronchospasm associated with

exposure to known precipitating factors, such as cold, dry air or allergens

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Mast Cell Stabilizers: Side Effects


Sore throat



Taste changes



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Mast Cell Stabilizers: Nursing Implications

For prophylactic use only Contraindicated for acute exacerbations Not recommended for children younger than age 5 Therapeutic effects may not be seen for up to 4

weeks Teach clients to gargle and rinse the mouth with

water afterward to minimize irritation to the throat and oral mucosa

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Inhalers:Client Education

For any inhaler prescribed, ensure that the client is able to self-administer the medication Provide demonstration and return demonstration Ensure the client knows the correct time

intervals for inhalers Provide a spacer if the client has difficulty

coordinating breathing with inhaler activation

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Client Education

Metered Dose Inhaler MDI





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Inhalers fall into two categories

Aerosol Inhalers: Pressurized metered dose inhaler is a canister filled with asthma medication suspended in a

propellant. When the canister is pushed down, a measured dose of the medication is pushed out as you breathe it in. Pressurized metered dose inhalers are commonly called

"puffers". Dry-powder inhalers: Dry powdered inhalers contain a dry

powder medication that is drawn into your lungs when you breathe in.

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Spacers should always be used with MDIs that deliver inhaled corticosteroids. Spacers can make it easier for medication to reach the lungs, and also mean less medication gets deposited in the mouth and throat, where it can lead to irritation and mild infections. The Asthma

Society of Canada recommends that anyone, of any age, using a puffer, consider using a spacer.

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