Bronchodilators and Other Respiratory Drugs

Asthma

Emphysema

Chronic bronchitis

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

Stimulate β2-adrenergic receptors throughout the lungs

Three types

Nonselective adrenergics

• Stimulate α, β1 (cardiac), and β2 (respiratory) receptors• Example: epinephrine

Nonselective β-adrenergics

• Stimulate both β1 and β2 receptors• Example: metaproterenol

Selective β2 drugs

• Stimulate only β2 receptors• Example: albuterol (Proventil)

Mechanism of Action

Begins at the specific receptor stimulated#

Ends 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

Relief of bronchospasm related to asthma, bronchitis, and other pulmonary diseases

Useful in treatment of acute attacks as well as prevention

Used in hypotension and shock

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

Hyperglycemia Tremor Cardiac stimulation

β1 and β2 (metaproterenol)

Cardiac stimulation Tremor Anginal pain

Vascular headache Hypotension

β2 (albuterol)

Hypotension OR hypertension Vascular headache Tremor

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

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• Have patients demonstrate use of devices

Monitor for adverse effects

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

Patients to get prompt treatment for flu or other illnesses

Patients to get vaccinated against pneumonia and flu

Check with their physician before taking any medication, including OTCs

Teach patients to take bronchodilators exactly as prescribed

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• No omissions or double doses

Report insomnia, jitteriness, restlessness, palpitations, chest pain, or any change in symptoms

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 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

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)

Dilate of airways in asthma, chronic bronchitis, and emphysema

Mild to moderate cases of acute asthma

Adjunct drug in the management of COPD

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

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 Nausea Vomiting • Weakness Dizziness Chest pain • Convulsions

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

Antileukotriene drugs• 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) zafirlukast (Accolate)

Headache HeadacheDyspepsia NauseaNausea DiarrheaDizziness Liver dysfunctionInsomniaLiver dysfunction

Montelukast (Singulair) has fewer adverse effects

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

Teach the patient the purpose of the therapy

Improvement should be seen in about 1 week

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 - chronic asthma/COPD exacerbations

Do not relieve acute asthmatic attacks S&S

Oral, IV (quick acting), or inhaled forms

Inhaled forms reduce systemic effects• May take several weeks before full

effects are seen

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

If 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

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).

 

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)