Drugs Affecting the Respiratory System Bronchodilators and Other

Drugs Affecting the Respiratory System Bronchodilators and Other Respiratory Drugs

Respiratory System Drugs Lower Respiratory Tract Diseases Asthma Emphysema Chronic bronchitis

Respiratory System Drugs Asthma 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

Respiratory System Drugs Asthma Status asthmaticus • Prolonged asthma attack that does not respond to typical drug therapy • May last several minutes to hours • Medical emergency

Respiratory System Drugs Chronic Bronchitis 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”

Respiratory System Drugs Emphysema 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 pa. CO 2 - respiratory acidosis • Difficulty exhaling – pursed lip breathing • “Pink Puffer”

Respiratory System Drugs COPD Drugs Long-term control • • Antileukotrienes cromolyn Inhaled steroids Long-acting β 2 -agonists Quick relief • Intravenous systemic corticosteroids • Short-acting inhaled β 2 -agonists

Respiratory System Drugs Bronchodilators • β-adrenergic agonists • Xanthine derivatives Anticholinergics Antileukotrienes Corticosteroids

Respiratory System Drugs Bronchodilators: β-Agonists Large group, sympathomimetics Used during acute phase of asthmatic attacks Quickly reduce airway constriction Stimulate β 2 -adrenergic receptors throughout the lungs

Respiratory System Drugs Bronchodilators: β-Agonists Three types Nonselective adrenergics • Stimulate α, β 1 (cardiac), and β 2 (respiratory) receptors • Example: epinephrine Nonselective β-adrenergics • Stimulate both β 1 and β 2 receptors • Example: metaproterenol Selective β 2 drugs • Stimulate only β 2 receptors • Example: albuterol (Proventil)

Respiratory System Drugs Bronchodilators: β-Agonists Mechanism of Action Begins at the specific receptor stimulated# Ends with the dilation of the airways • #Activation of β 2 receptors activates c. AMP, * which relaxes smooth muscles of the airway and results in bronchial dilation and increased airflow *c. AMP = cyclic adenosine monophosphate

Respiratory System Drugs Bronchodilators: β-Agonists 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

Respiratory System Drugs β-Agonists: Adverse Effects α-β (epinephrine) Insomnia Restlessness Anorexia Vascular headache Hyperglycemia Tremor Cardiac stimulation

Respiratory System Drugs β-Agonists: Adverse Effects β 1 and β 2 (metaproterenol) Cardiac stimulation Tremor Anginal pain Vascular headache Hypotension

Respiratory System Drugs β-Agonists: Adverse Effects β 2 (albuterol) Hypotension OR hypertension Vascular headache Tremor

Respiratory System Drugs β-Agonists Nursing Implications Thorough assessment before beginning therapy • Skin color • Baseline vital signs • Respirations (should be between 12 and 24 • • • breaths/min) Respiratory assessment, including PO 2 Sputum production Allergies History of respiratory problems Other medications

Respiratory System Drugs β-Agonists - Nursing Implications 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

Respiratory System Drugs β-Agonists - Patient Education 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

Respiratory System Drugs β-Agonist Derivatives Nsg Implications Albuterol, if used too frequently, loses its β 2 -specific actions at larger doses • As a result, β 1 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

Inhalers: Patient Education 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

Respiratory System Drugs 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 ipratropium bromide (Atrovent) and tiotropium (Spiriva) Slow and prolonged action Used to prevent bronchoconstriction NOT used for acute asthma exacerbations!

Respiratory System Drugs Anticholinergics Adverse effects Dry mouth or throat Nasal congestion Heart palpitations Gastrointestinal distress Headache Coughing Anxiety No known drug interactions

Respiratory System Drugs Bronchodilators Xanthine Derivatives Plant alkaloids: • caffeine, theobromine, and theophylline Only theophylline is used as a bronchodilator Synthetic xanthines: (IV) theophylline (Aminophylline) (oral) theophylline (Elixophyllin, Theo-Dur)

Respiratory System Drugs Bronchodilators Xanthine Derivatives Increase levels of energy-producing c. AMP • This is done competitively inhibiting phosphodiesterase (PDE), the enzyme that breaks down c. AMP (c. AMP = cyclic adenosine monophosphate) Result: • decreased c. AMP 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)

Respiratory System Drugs Bronchodilators Xanthine Derivatives 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

Xanthine Derivatives: Adverse Effects Nausea, vomiting, anorexia Gastroesophageal reflux during sleep Sinus tachycardia, extrasystoles, palpitations, ventricular dysrhythmias Transient increased urination

Xanthine Derivatives Nursing Implications 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

Respiratory System Drugs Antileukotrienes Also called leukotriene receptor antagonists (LRTAs) Newer class of asthma drugs Currently available drugs montelukast (Singulair) zafirlukast (Accolate) zileuton (Zyflo)

Respiratory System Drugs Antileukotrienes 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

Respiratory System Drugs Mechanism of Action 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

Respiratory System Drugs 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 (Singulair) • is approved for use in children ages 2 and older, and for treatment of allergic rhinitis

Respiratory System Drugs Antileukotrienes: Adverse Effects zileuton (Zyflo) zafirlukast (Accolate) Headache Dyspepsia Nausea Dizziness Insomnia Liver dysfunction Headache Nausea Diarrhea Liver dysfunction Montelukast (Singulair) has fewer adverse effects

Respiratory System Drugs Nursing Implications – Pt Ed Ensure that the drug is being used for chronic management of asthma, not acute asthma Teach the patient the purpose of 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

Respiratory System Drugs Corticosteroids 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

Respiratory System Drugs Corticosteroids Mechanism of Action Stabilize membranes of cells that release harmful bronchoconstricting substances Also increase responsiveness of bronchial smooth muscle to β-adrenergic stimulation

Respiratory System Drugs Inhaled Corticosteroids beclomethasone dipropionate (Beclovent, Vanceril) triamcinolone acetonide (Azmacort) dexamethasone sodium phosphate (Decadron Phosphate Respihaler) fluticasone (Flovent, Flonase)

Respiratory System Drugs Corticosteroids - Indications 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

Respiratory System Drugs Corticosteroids - Adverse Effects Pharyngeal irritation Coughing Dry mouth Oral fungal infections Systemic effects are rare because of the low doses used for inhalation therapy

Corticosteroids Nursing Implications – Pt Education 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

Corticosteroids Nursing Implications – Pt Education 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

Review 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: __________.

Review Answers 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/m. L; some practitioners recommend 5 to 15 mcg/m. L 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).

Review 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 β 1 agonist 6. epinephrine, intravenous dose, an alpha-beta agonist

Review Answers 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)