1 / 25

Chapter 76

Chapter 76. Drugs for Asthma. Asthma. Chronic inflammatory disorder of the airway Characteristic signs and symptoms Sense of breathlessness Tightening of the chest Wheezing Dyspnea Cough Cause: immune-mediated airway inflammation. Pathophysiology.

freja
Download Presentation

Chapter 76

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 76 Drugs for Asthma

  2. Asthma • Chronic inflammatory disorder of the airway • Characteristic signs and symptoms • Sense of breathlessness • Tightening of the chest • Wheezing • Dyspnea • Cough • Cause: immune-mediated airway inflammation

  3. Pathophysiology • Symptoms of asthma result from a combination of inflammation and bronchoconstriction, so treatment must address both components

  4. Overview of Drugs for Asthma • Two main pharmacologic classes • Anti-inflammatory agents • Glucocorticoids (prednisone) • Bronchodilators • Beta2 agonists (albuterol)

  5. Inhalation Drug Therapy • Three obvious advantages • Therapeutic effects are enhanced • Systemic effects are minimized • Relief of acute attacks is rapid • Three types • Metered-dose inhalers (MDIs) • Dry-powder inhalers (DPIs) • Nebulizers

  6. Anti-Inflammatory Drugs • Foundation of asthma therapy • Taken daily for long-term control • Principal anti-inflammatory drugs are the glucocorticoids

  7. Anti-Inflammatory Drugs:Glucocorticoids • Include budesonide and fluticasone • Considered the most effective anti-asthma drugs available • Reduce bronchial hyperreactivity • Also decrease airway mucus production and increase the number of bronchial beta2 receptors as well as their responsiveness to beta2 agonists. • Usually administered by inhalation, but IV and oral are also options

  8. Anti-Inflammatory Drugs:Glucocorticoids • Mechanism of action = Suppress inflammation • Decreased synthesis and release of inflammatory mediators • Decreased infiltration and activity of inflammatory cells • Decreased edema of the airway mucosa

  9. Anti-Inflammatory Drugs:Glucocorticoids • Adverse effects • Minor when taken acutely • Can be severe when used long-term (adrenal suppression, osteoporosis, hyperglycemia, and others)

  10. Anti-Inflammatory Drugs:Leukotriene Modifiers • Suppress effects of leukotrienes • Less effective than inhaled glucocorticoids • Available agents • Zileuton (Zyflo) • Zafirlukast (Accolate) • Montelukast (Singulair)

  11. Anti-Inflammatory Drugs:Cromolyn • Used for prophylaxis, not for quick relief • Suppresses inflammation; not a bronchodilator • Route—inhalation • Nebulizer • MDI • Adverse effects • Safest of all antiasthma medications • Cough • Bronchospasm

  12. Bronchodilators • Provide symptomatic relief but do not alter the underlying disease process (inflammation) • In almost all cases, patient taking a bronchodilator should also be taking a glucocorticoid for long-term suppression of inflammation • Principal bronchodilators are the beta2-adrenergic agonists

  13. Bronchodilators: Beta2-Adrenergic Agonists • Include albuterol, salmeterol, terbutaline • Most effective drugs for relief of acute bronchospasm and prevention of exercise-induced bronchospasm • Use in asthma: both quick relief and long-term control

  14. Bronchodilators: Beta2-Adrenergic Agonists • Adverse effects • Inhaled preparations • Systemic effects: tachycardia, angina, and tremor • Oral preparations • Excessive dosage: angina pectoris, tachydysrhythmias • Tremor

  15. Bronchodilators: Beta2-Adrenergic Agonists • Mechanism of action • Activate beta2 receptors in smooth muscle of lung, promoting bronchodilation and thereby relieving bronchospasm • Also suppress histamine release in lung and increase ciliary motility

  16. Bronchodilators: Methylxanthines • Theophylline • Benefits derive primarily from bronchodilation • Narrow therapeutic index • Plasma level 10 to 20 mcg/mL • Toxicity is related to theophylline levels • Other methylxanthines include aminophylline and dyphylline

  17. Glucocorticoid/LABA Combinations • Available combinations • Fluticasone/salmeterol (Advair) • Budesonide/formoterol (Symbicort) • Indicated for long-term maintenance in adults and children • Not recommended for initial therapy LABA = long-acting beta2agonist.

  18. Management of Chronic Asthma • Tests of lung function • Forced expiratory volume in 1 second (FEV1) • Forced vital capacity (FVC) • Peak expiratory flow (PEF)

  19. Management of Chronic Asthma • Four classes of chronic asthma • Intermittent • Mild persistent • Moderate persistent • Severe persistent

  20. Management of Chronic Asthma • Treatment goals • Reducing impairment • Reducing risk

  21. Management of Chronic Asthma • Long-term drug therapy • Agents for long-term control (eg, inhaled glucocorticoids) • Agents for quick relief of ongoing attack (eg, inhaled SABAs)

  22. Management of Chronic Asthma • Stepwise therapy • Step chosen for initial therapy is based on pretreatment classification of asthma severity • Moving up or down a step is based on ongoing assessment of asthma control

  23. Management of Chronic Asthma • Important to reduce exposure to allergens and triggers • Sources of allergens: house dust mites, pets, cockroaches, mold • Factors that can exacerbate asthma: tobacco smoke, wood smoke, household sprays

  24. Drugs for Acute Severe Exacerbations • Requires immediate attention • Goal is to relieve airway obstruction and hypoxemia, and normalize lung function as quickly as possible. • Initial therapy consists of • Giving oxygen to relieve hypoxemia • Giving a systemic glucocorticoid to reduce airway inflammation • Giving a nebulized high-dose SABA to relieve airflow obstruction • Giving nebulizedipratropium to further reduce airflow obstruction.

  25. Reducing Exposure to Allergens and Triggers • Measures to control or avoid dust mites and their feces include • Encasing the patient’s pillow, mattress, and box spring with covers that are impermeable to allergens • Washing all bedding and stuffed animals weekly in a hot-water wash cycle (130 °F) • Removing carpeting or rugs from the bedroom • Avoiding sleeping or lying on upholstered furniture • Keeping indoor humidity below 50%

More Related